lmbench ctxsw regression with CFS

lmbench ctxsw regression with CFS

[Nick Piggin]

Hi,

I didn't follow all of the scheduler debates and flamewars, so apologies
if this was already covered. Anyway.

lmbench 3 lat_ctx context switching time with 2 processes bound to a
single core increases by between 25%-35% on my Core2 system (didn't do
enough runs to get more significance, but it is around 30%). The problem
bisected to the main CFS commit.

I was really hoping that a smaller runqueue data structure could actually
increase performance with the common case of small numbers of tasks :(

I assume this was a known issue before CFS was merged. Do you know what is
causing the slowdown? Any plans to fix it?

Thanks,
Nick

Re: lmbench ctxsw regression with CFS

[Linus Torvalds]

On Thu, 2 Aug 2007, Nick Piggin wrote:
> 
> lmbench 3 lat_ctx context switching time with 2 processes bound to a
> single core increases by between 25%-35% on my Core2 system (didn't do
> enough runs to get more significance, but it is around 30%). The problem
> bisected to the main CFS commit.

One thing to check out is whether the lmbench numbers are "correct". 
Especially on SMP systems, the lmbench numbers are actually *best* when 
the two processes run on the same CPU, even though that's not really at 
all the best scheduling - it's just that it artificially improves lmbench 
numbers because of the close cache affinity for the pipe data structures.

So when running the lmbench scheduling benchmarks on SMP, it actually 
makes sense to run them *pinned* to one CPU, because then you see the true 
scheduler performance. Otherwise you easily get noise due to balancing 
issues, and a clearly better scheduler can in fact generate worse 
numbers for lmbench.

Did you do that? It's at least worth testing. I'm not saying it's the case 
here, but it's one reason why lmbench3 has the option to either keep 
processes on the same CPU or force them to spread out (and both cases are 
very interesting for scheduler testing, and tell different things: the 
"pin them to the same CPU" shows the latency on one runqueue, while the 
"pin them to different CPU's" shows the latency of a remote wakeup).

IOW, while we used the lmbench scheduling benchmark pretty extensively in 
early scheduler tuning, if you select the defaults ("let the system just 
schedule processes on any CPU") the end result really isn't necessarily a 
very meaningful value: getting the best lmbench numbers actually requires 
you to do things that tend to be actively *bad* in real life.

Of course, a perfect scheduler would notice when two tasks are *so* 
closely related and only do synchronous wakups, that it would keep them on 
the same core, and get the best possible scores for lmbench, while not 
doing that for other real-life situations. So with a *really* smart 
scheduler, lmbench numbers would always be optimal, but I'm not sure 
aiming for that kind of perfection is even worth it!

		Linus

Re: lmbench ctxsw regression with CFS

[Nick Piggin]

On Wed, Aug 01, 2007 at 07:31:26PM -0700, Linus Torvalds wrote:
> 
> 
> On Thu, 2 Aug 2007, Nick Piggin wrote:
> > 
> > lmbench 3 lat_ctx context switching time with 2 processes bound to a
> > single core increases by between 25%-35% on my Core2 system (didn't do
> > enough runs to get more significance, but it is around 30%). The problem
> > bisected to the main CFS commit.
> 
> One thing to check out is whether the lmbench numbers are "correct". 
> Especially on SMP systems, the lmbench numbers are actually *best* when 
> the two processes run on the same CPU, even though that's not really at 
> all the best scheduling - it's just that it artificially improves lmbench 
> numbers because of the close cache affinity for the pipe data structures.

Yes, I bound them to a single core.


> So when running the lmbench scheduling benchmarks on SMP, it actually 
> makes sense to run them *pinned* to one CPU, because then you see the true 
> scheduler performance. Otherwise you easily get noise due to balancing 
> issues, and a clearly better scheduler can in fact generate worse 
> numbers for lmbench.
> 
> Did you do that? It's at least worth testing. I'm not saying it's the case 
> here, but it's one reason why lmbench3 has the option to either keep 
> processes on the same CPU or force them to spread out (and both cases are 
> very interesting for scheduler testing, and tell different things: the 
> "pin them to the same CPU" shows the latency on one runqueue, while the 
> "pin them to different CPU's" shows the latency of a remote wakeup).
> 
> IOW, while we used the lmbench scheduling benchmark pretty extensively in 
> early scheduler tuning, if you select the defaults ("let the system just 
> schedule processes on any CPU") the end result really isn't necessarily a 
> very meaningful value: getting the best lmbench numbers actually requires 
> you to do things that tend to be actively *bad* in real life.
> 
> Of course, a perfect scheduler would notice when two tasks are *so* 
> closely related and only do synchronous wakups, that it would keep them on 
> the same core, and get the best possible scores for lmbench, while not 
> doing that for other real-life situations. So with a *really* smart 
> scheduler, lmbench numbers would always be optimal, but I'm not sure 
> aiming for that kind of perfection is even worth it!

Agreed with all your comments on multiprocessor balancing, but that
was eliminated in these tests. I remote wakeup latency is another thing
I want to test, but it isn't so interesting until the serial regression
is fixed.

Re: lmbench ctxsw regression with CFS

[Ingo Molnar]

* Nick Piggin <npiggin@suse.de> wrote:

> > One thing to check out is whether the lmbench numbers are "correct". 
> > Especially on SMP systems, the lmbench numbers are actually *best* 
> > when the two processes run on the same CPU, even though that's not 
> > really at all the best scheduling - it's just that it artificially 
> > improves lmbench numbers because of the close cache affinity for the 
> > pipe data structures.
> 
> Yes, I bound them to a single core.

could you send me the .config you used?

	Ingo

Re: lmbench ctxsw regression with CFS

[Nick Piggin]

On Thu, Aug 02, 2007 at 09:19:56AM +0200, Ingo Molnar wrote:
> 
> * Nick Piggin <npiggin@suse.de> wrote:
> 
> > > One thing to check out is whether the lmbench numbers are "correct". 
> > > Especially on SMP systems, the lmbench numbers are actually *best* 
> > > when the two processes run on the same CPU, even though that's not 
> > > really at all the best scheduling - it's just that it artificially 
> > > improves lmbench numbers because of the close cache affinity for the 
> > > pipe data structures.
> > 
> > Yes, I bound them to a single core.
> 
> could you send me the .config you used?

Sure, attached...

You don't see a regression? If not, then can you send me the .config you
used? Also what CPU architecture (when I tested an older CFS on a P4 IIRC
the regression was much bigger like 100% more costly).

---

#
# Automatically generated make config: don't edit
# Linux kernel version: 2.6.23-rc1
# Tue Jul 31 21:43:43 2007
#
CONFIG_X86_64=y
CONFIG_64BIT=y
CONFIG_X86=y
CONFIG_GENERIC_TIME=y
CONFIG_GENERIC_TIME_VSYSCALL=y
CONFIG_GENERIC_CMOS_UPDATE=y
CONFIG_ZONE_DMA32=y
CONFIG_LOCKDEP_SUPPORT=y
CONFIG_STACKTRACE_SUPPORT=y
CONFIG_SEMAPHORE_SLEEPERS=y
CONFIG_MMU=y
CONFIG_ZONE_DMA=y
CONFIG_QUICKLIST=y
CONFIG_NR_QUICK=2
CONFIG_RWSEM_GENERIC_SPINLOCK=y
CONFIG_GENERIC_HWEIGHT=y
CONFIG_GENERIC_CALIBRATE_DELAY=y
CONFIG_X86_CMPXCHG=y
CONFIG_EARLY_PRINTK=y
CONFIG_GENERIC_ISA_DMA=y
CONFIG_GENERIC_IOMAP=y
CONFIG_ARCH_MAY_HAVE_PC_FDC=y
CONFIG_ARCH_POPULATES_NODE_MAP=y
CONFIG_DMI=y
CONFIG_AUDIT_ARCH=y
CONFIG_GENERIC_BUG=y
# CONFIG_ARCH_HAS_ILOG2_U32 is not set
# CONFIG_ARCH_HAS_ILOG2_U64 is not set
CONFIG_DEFCONFIG_LIST="/lib/modules/$UNAME_RELEASE/.config"

#
# Code maturity level options
#
CONFIG_EXPERIMENTAL=y
CONFIG_LOCK_KERNEL=y
CONFIG_INIT_ENV_ARG_LIMIT=32

#
# General setup
#
CONFIG_LOCALVERSION=""
CONFIG_LOCALVERSION_AUTO=y
CONFIG_SWAP=y
CONFIG_SYSVIPC=y
CONFIG_SYSVIPC_SYSCTL=y
CONFIG_POSIX_MQUEUE=y
# CONFIG_BSD_PROCESS_ACCT is not set
# CONFIG_TASKSTATS is not set
# CONFIG_USER_NS is not set
# CONFIG_AUDIT is not set
CONFIG_IKCONFIG=y
CONFIG_IKCONFIG_PROC=y
CONFIG_LOG_BUF_SHIFT=18
# CONFIG_CPUSETS is not set
# CONFIG_SYSFS_DEPRECATED is not set
# CONFIG_RELAY is not set
# CONFIG_BLK_DEV_INITRD is not set
CONFIG_CC_OPTIMIZE_FOR_SIZE=y
CONFIG_SYSCTL=y
CONFIG_EMBEDDED=y
# CONFIG_UID16 is not set
CONFIG_SYSCTL_SYSCALL=y
CONFIG_KALLSYMS=y
# CONFIG_KALLSYMS_EXTRA_PASS is not set
CONFIG_HOTPLUG=y
CONFIG_PRINTK=y
CONFIG_BUG=y
CONFIG_ELF_CORE=y
CONFIG_BASE_FULL=y
CONFIG_FUTEX=y
CONFIG_ANON_INODES=y
CONFIG_EPOLL=y
CONFIG_SIGNALFD=y
CONFIG_TIMERFD=y
CONFIG_EVENTFD=y
CONFIG_SHMEM=y
CONFIG_VM_EVENT_COUNTERS=y
CONFIG_SLAB=y
# CONFIG_SLUB is not set
# CONFIG_SLOB is not set
CONFIG_RT_MUTEXES=y
# CONFIG_TINY_SHMEM is not set
CONFIG_BASE_SMALL=0
CONFIG_MODULES=y
CONFIG_MODULE_UNLOAD=y
CONFIG_MODULE_FORCE_UNLOAD=y
# CONFIG_MODVERSIONS is not set
# CONFIG_MODULE_SRCVERSION_ALL is not set
# CONFIG_KMOD is not set
CONFIG_STOP_MACHINE=y
CONFIG_BLOCK=y
# CONFIG_BLK_DEV_IO_TRACE is not set
CONFIG_BLK_DEV_BSG=y

#
# IO Schedulers
#
CONFIG_IOSCHED_NOOP=y
CONFIG_IOSCHED_AS=y
CONFIG_IOSCHED_DEADLINE=y
CONFIG_IOSCHED_CFQ=y
CONFIG_DEFAULT_AS=y
# CONFIG_DEFAULT_DEADLINE is not set
# CONFIG_DEFAULT_CFQ is not set
# CONFIG_DEFAULT_NOOP is not set
CONFIG_DEFAULT_IOSCHED="anticipatory"

#
# Processor type and features
#
CONFIG_X86_PC=y
# CONFIG_X86_VSMP is not set
# CONFIG_MK8 is not set
# CONFIG_MPSC is not set
CONFIG_MCORE2=y
# CONFIG_GENERIC_CPU is not set
CONFIG_X86_L1_CACHE_BYTES=64
CONFIG_X86_L1_CACHE_SHIFT=6
CONFIG_X86_INTERNODE_CACHE_BYTES=64
CONFIG_X86_TSC=y
CONFIG_X86_GOOD_APIC=y
CONFIG_MICROCODE=y
CONFIG_MICROCODE_OLD_INTERFACE=y
CONFIG_X86_MSR=y
CONFIG_X86_CPUID=y
CONFIG_X86_HT=y
CONFIG_X86_IO_APIC=y
CONFIG_X86_LOCAL_APIC=y
CONFIG_MTRR=y
CONFIG_SMP=y
# CONFIG_SCHED_SMT is not set
CONFIG_SCHED_MC=y
CONFIG_PREEMPT_NONE=y
# CONFIG_PREEMPT_VOLUNTARY is not set
# CONFIG_PREEMPT is not set
# CONFIG_PREEMPT_BKL is not set
# CONFIG_NUMA is not set
CONFIG_ARCH_SPARSEMEM_ENABLE=y
CONFIG_ARCH_FLATMEM_ENABLE=y
CONFIG_SELECT_MEMORY_MODEL=y
CONFIG_FLATMEM_MANUAL=y
# CONFIG_DISCONTIGMEM_MANUAL is not set
# CONFIG_SPARSEMEM_MANUAL is not set
CONFIG_FLATMEM=y
CONFIG_FLAT_NODE_MEM_MAP=y
# CONFIG_SPARSEMEM_STATIC is not set
CONFIG_SPLIT_PTLOCK_CPUS=4
CONFIG_RESOURCES_64BIT=y
CONFIG_ZONE_DMA_FLAG=1
CONFIG_BOUNCE=y
CONFIG_VIRT_TO_BUS=y
CONFIG_NR_CPUS=2
CONFIG_PHYSICAL_ALIGN=0x200000
CONFIG_HOTPLUG_CPU=y
CONFIG_ARCH_ENABLE_MEMORY_HOTPLUG=y
CONFIG_HPET_TIMER=y
CONFIG_HPET_EMULATE_RTC=y
# CONFIG_IOMMU is not set
# CONFIG_CALGARY_IOMMU is not set
CONFIG_X86_MCE=y
CONFIG_X86_MCE_INTEL=y
# CONFIG_X86_MCE_AMD is not set
CONFIG_KEXEC=y
CONFIG_CRASH_DUMP=y
CONFIG_RELOCATABLE=y
CONFIG_PHYSICAL_START=0x200000
# CONFIG_SECCOMP is not set
# CONFIG_CC_STACKPROTECTOR is not set
CONFIG_HZ_100=y
# CONFIG_HZ_250 is not set
# CONFIG_HZ_300 is not set
# CONFIG_HZ_1000 is not set
CONFIG_HZ=100
CONFIG_GENERIC_HARDIRQS=y
CONFIG_GENERIC_IRQ_PROBE=y
CONFIG_ISA_DMA_API=y
CONFIG_GENERIC_PENDING_IRQ=y

#
# Power management options
#
CONFIG_PM=y
# CONFIG_PM_LEGACY is not set
# CONFIG_PM_DEBUG is not set
CONFIG_SUSPEND_SMP_POSSIBLE=y
CONFIG_SUSPEND_SMP=y
CONFIG_PM_SLEEP=y
CONFIG_SUSPEND=y
# CONFIG_HIBERNATION is not set
CONFIG_ACPI=y
CONFIG_ACPI_SLEEP=y
CONFIG_ACPI_PROCFS=y
# CONFIG_ACPI_PROCFS_SLEEP is not set
CONFIG_ACPI_AC=y
CONFIG_ACPI_BATTERY=y
CONFIG_ACPI_BUTTON=y
# CONFIG_ACPI_VIDEO is not set
CONFIG_ACPI_FAN=y
# CONFIG_ACPI_DOCK is not set
CONFIG_ACPI_PROCESSOR=y
CONFIG_ACPI_HOTPLUG_CPU=y
CONFIG_ACPI_THERMAL=y
# CONFIG_ACPI_ASUS is not set
# CONFIG_ACPI_TOSHIBA is not set
CONFIG_ACPI_BLACKLIST_YEAR=0
# CONFIG_ACPI_DEBUG is not set
CONFIG_ACPI_EC=y
CONFIG_ACPI_POWER=y
CONFIG_ACPI_SYSTEM=y
CONFIG_X86_PM_TIMER=y
CONFIG_ACPI_CONTAINER=y
# CONFIG_ACPI_SBS is not set

#
# CPU Frequency scaling
#
CONFIG_CPU_FREQ=y
CONFIG_CPU_FREQ_TABLE=y
# CONFIG_CPU_FREQ_DEBUG is not set
CONFIG_CPU_FREQ_STAT=y
# CONFIG_CPU_FREQ_STAT_DETAILS is not set
CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE=y
# CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE is not set
CONFIG_CPU_FREQ_GOV_PERFORMANCE=y
CONFIG_CPU_FREQ_GOV_POWERSAVE=y
CONFIG_CPU_FREQ_GOV_USERSPACE=y
CONFIG_CPU_FREQ_GOV_ONDEMAND=y
# CONFIG_CPU_FREQ_GOV_CONSERVATIVE is not set

#
# CPUFreq processor drivers
#
# CONFIG_X86_POWERNOW_K8 is not set
# CONFIG_X86_SPEEDSTEP_CENTRINO is not set
CONFIG_X86_ACPI_CPUFREQ=y

#
# shared options
#
# CONFIG_X86_ACPI_CPUFREQ_PROC_INTF is not set
# CONFIG_X86_P4_CLOCKMOD is not set
# CONFIG_X86_SPEEDSTEP_LIB is not set

#
# Bus options (PCI etc.)
#
CONFIG_PCI=y
CONFIG_PCI_DIRECT=y
CONFIG_PCI_MMCONFIG=y
CONFIG_PCIEPORTBUS=y
CONFIG_PCIEAER=y
CONFIG_ARCH_SUPPORTS_MSI=y
CONFIG_PCI_MSI=y
# CONFIG_HT_IRQ is not set

#
# PCCARD (PCMCIA/CardBus) support
#
CONFIG_PCCARD=y
# CONFIG_PCMCIA_DEBUG is not set
# CONFIG_PCMCIA is not set
CONFIG_CARDBUS=y

#
# PC-card bridges
#
CONFIG_YENTA=y
# CONFIG_YENTA_O2 is not set
# CONFIG_YENTA_RICOH is not set
CONFIG_YENTA_TI=y
CONFIG_YENTA_ENE_TUNE=y
# CONFIG_YENTA_TOSHIBA is not set
CONFIG_PCCARD_NONSTATIC=y
# CONFIG_HOTPLUG_PCI is not set

#
# Executable file formats / Emulations
#
CONFIG_BINFMT_ELF=y
CONFIG_BINFMT_MISC=y
CONFIG_IA32_EMULATION=y
# CONFIG_IA32_AOUT is not set
CONFIG_COMPAT=y
CONFIG_COMPAT_FOR_U64_ALIGNMENT=y
CONFIG_SYSVIPC_COMPAT=y

#
# Networking
#
CONFIG_NET=y

#
# Networking options
#
CONFIG_PACKET=y
CONFIG_PACKET_MMAP=y
CONFIG_UNIX=y
CONFIG_XFRM=y
CONFIG_XFRM_USER=y
# CONFIG_XFRM_SUB_POLICY is not set
# CONFIG_XFRM_MIGRATE is not set
CONFIG_NET_KEY=y
# CONFIG_NET_KEY_MIGRATE is not set
CONFIG_INET=y
CONFIG_IP_MULTICAST=y
# CONFIG_IP_ADVANCED_ROUTER is not set
CONFIG_IP_FIB_HASH=y
# CONFIG_IP_PNP is not set
# CONFIG_NET_IPIP is not set
# CONFIG_NET_IPGRE is not set
# CONFIG_IP_MROUTE is not set
# CONFIG_ARPD is not set
# CONFIG_SYN_COOKIES is not set
# CONFIG_INET_AH is not set
# CONFIG_INET_ESP is not set
CONFIG_INET_IPCOMP=y
CONFIG_INET_XFRM_TUNNEL=y
CONFIG_INET_TUNNEL=y
CONFIG_INET_XFRM_MODE_TRANSPORT=y
CONFIG_INET_XFRM_MODE_TUNNEL=y
CONFIG_INET_XFRM_MODE_BEET=y
CONFIG_INET_DIAG=y
CONFIG_INET_TCP_DIAG=y
# CONFIG_TCP_CONG_ADVANCED is not set
CONFIG_TCP_CONG_CUBIC=y
CONFIG_DEFAULT_TCP_CONG="cubic"
CONFIG_TCP_MD5SIG=y
# CONFIG_IP_VS is not set
# CONFIG_IPV6 is not set
# CONFIG_INET6_XFRM_TUNNEL is not set
# CONFIG_INET6_TUNNEL is not set
# CONFIG_NETWORK_SECMARK is not set
CONFIG_NETFILTER=y
# CONFIG_NETFILTER_DEBUG is not set

#
# Core Netfilter Configuration
#
CONFIG_NETFILTER_NETLINK=y
CONFIG_NETFILTER_NETLINK_QUEUE=y
CONFIG_NETFILTER_NETLINK_LOG=y
# CONFIG_NF_CONNTRACK_ENABLED is not set
# CONFIG_NF_CONNTRACK is not set
CONFIG_NETFILTER_XTABLES=y
# CONFIG_NETFILTER_XT_TARGET_CLASSIFY is not set
# CONFIG_NETFILTER_XT_TARGET_MARK is not set
# CONFIG_NETFILTER_XT_TARGET_NFQUEUE is not set
# CONFIG_NETFILTER_XT_TARGET_NFLOG is not set
# CONFIG_NETFILTER_XT_TARGET_TRACE is not set
# CONFIG_NETFILTER_XT_TARGET_TCPMSS is not set
# CONFIG_NETFILTER_XT_MATCH_COMMENT is not set
# CONFIG_NETFILTER_XT_MATCH_DCCP is not set
# CONFIG_NETFILTER_XT_MATCH_DSCP is not set
# CONFIG_NETFILTER_XT_MATCH_ESP is not set
CONFIG_NETFILTER_XT_MATCH_LENGTH=y
CONFIG_NETFILTER_XT_MATCH_LIMIT=y
CONFIG_NETFILTER_XT_MATCH_MAC=y
CONFIG_NETFILTER_XT_MATCH_MARK=y
CONFIG_NETFILTER_XT_MATCH_POLICY=y
CONFIG_NETFILTER_XT_MATCH_MULTIPORT=y
CONFIG_NETFILTER_XT_MATCH_PKTTYPE=y
# CONFIG_NETFILTER_XT_MATCH_QUOTA is not set
# CONFIG_NETFILTER_XT_MATCH_REALM is not set
# CONFIG_NETFILTER_XT_MATCH_SCTP is not set
# CONFIG_NETFILTER_XT_MATCH_STATISTIC is not set
# CONFIG_NETFILTER_XT_MATCH_STRING is not set
# CONFIG_NETFILTER_XT_MATCH_TCPMSS is not set
# CONFIG_NETFILTER_XT_MATCH_U32 is not set
# CONFIG_NETFILTER_XT_MATCH_HASHLIMIT is not set

#
# IP: Netfilter Configuration
#
# CONFIG_IP_NF_QUEUE is not set
CONFIG_IP_NF_IPTABLES=y
CONFIG_IP_NF_MATCH_IPRANGE=y
# CONFIG_IP_NF_MATCH_TOS is not set
# CONFIG_IP_NF_MATCH_RECENT is not set
# CONFIG_IP_NF_MATCH_ECN is not set
# CONFIG_IP_NF_MATCH_AH is not set
# CONFIG_IP_NF_MATCH_TTL is not set
CONFIG_IP_NF_MATCH_OWNER=y
CONFIG_IP_NF_MATCH_ADDRTYPE=y
CONFIG_IP_NF_FILTER=y
CONFIG_IP_NF_TARGET_REJECT=y
CONFIG_IP_NF_TARGET_LOG=y
CONFIG_IP_NF_TARGET_ULOG=y
# CONFIG_IP_NF_MANGLE is not set
CONFIG_IP_NF_RAW=y
CONFIG_IP_NF_ARPTABLES=y
CONFIG_IP_NF_ARPFILTER=y
CONFIG_IP_NF_ARP_MANGLE=y
# CONFIG_IP_DCCP is not set
# CONFIG_IP_SCTP is not set
# CONFIG_TIPC is not set
# CONFIG_ATM is not set
# CONFIG_BRIDGE is not set
# CONFIG_VLAN_8021Q is not set
# CONFIG_DECNET is not set
# CONFIG_LLC2 is not set
# CONFIG_IPX is not set
# CONFIG_ATALK is not set
# CONFIG_X25 is not set
# CONFIG_LAPB is not set
# CONFIG_ECONET is not set
# CONFIG_WAN_ROUTER is not set

#
# QoS and/or fair queueing
#
# CONFIG_NET_SCHED is not set

#
# Network testing
#
# CONFIG_NET_PKTGEN is not set
# CONFIG_HAMRADIO is not set
# CONFIG_IRDA is not set
# CONFIG_BT is not set
# CONFIG_AF_RXRPC is not set

#
# Wireless
#
# CONFIG_CFG80211 is not set
# CONFIG_WIRELESS_EXT is not set
# CONFIG_MAC80211 is not set
# CONFIG_IEEE80211 is not set
# CONFIG_RFKILL is not set
# CONFIG_NET_9P is not set

#
# Device Drivers
#

#
# Generic Driver Options
#
CONFIG_STANDALONE=y
CONFIG_PREVENT_FIRMWARE_BUILD=y
CONFIG_FW_LOADER=y
# CONFIG_SYS_HYPERVISOR is not set
CONFIG_CONNECTOR=y
CONFIG_PROC_EVENTS=y
# CONFIG_MTD is not set
CONFIG_PARPORT=y
CONFIG_PARPORT_PC=y
# CONFIG_PARPORT_SERIAL is not set
CONFIG_PARPORT_PC_FIFO=y
CONFIG_PARPORT_PC_SUPERIO=y
# CONFIG_PARPORT_GSC is not set
# CONFIG_PARPORT_AX88796 is not set
CONFIG_PARPORT_1284=y
CONFIG_PNP=y
# CONFIG_PNP_DEBUG is not set

#
# Protocols
#
CONFIG_PNPACPI=y
CONFIG_BLK_DEV=y
CONFIG_BLK_DEV_FD=y
# CONFIG_PARIDE is not set
# CONFIG_BLK_CPQ_DA is not set
# CONFIG_BLK_CPQ_CISS_DA is not set
# CONFIG_BLK_DEV_DAC960 is not set
# CONFIG_BLK_DEV_UMEM is not set
# CONFIG_BLK_DEV_COW_COMMON is not set
CONFIG_BLK_DEV_LOOP=y
# CONFIG_BLK_DEV_CRYPTOLOOP is not set
# CONFIG_BLK_DEV_NBD is not set
# CONFIG_BLK_DEV_SX8 is not set
# CONFIG_BLK_DEV_UB is not set
# CONFIG_BLK_DEV_RAM is not set
# CONFIG_CDROM_PKTCDVD is not set
# CONFIG_ATA_OVER_ETH is not set
CONFIG_MISC_DEVICES=y
# CONFIG_IBM_ASM is not set
# CONFIG_PHANTOM is not set
# CONFIG_EEPROM_93CX6 is not set
# CONFIG_SGI_IOC4 is not set
# CONFIG_TIFM_CORE is not set
# CONFIG_ASUS_LAPTOP is not set
# CONFIG_MSI_LAPTOP is not set
# CONFIG_SONY_LAPTOP is not set
CONFIG_THINKPAD_ACPI=y
# CONFIG_THINKPAD_ACPI_DEBUG is not set
# CONFIG_THINKPAD_ACPI_DOCK is not set
# CONFIG_THINKPAD_ACPI_BAY is not set
CONFIG_THINKPAD_ACPI_INPUT_ENABLED=y
CONFIG_IDE=y
CONFIG_IDE_MAX_HWIFS=4
# CONFIG_BLK_DEV_IDE is not set
# CONFIG_BLK_DEV_HD_ONLY is not set
# CONFIG_BLK_DEV_HD is not set

#
# SCSI device support
#
# CONFIG_RAID_ATTRS is not set
CONFIG_SCSI=y
CONFIG_SCSI_DMA=y
# CONFIG_SCSI_TGT is not set
# CONFIG_SCSI_NETLINK is not set
# CONFIG_SCSI_PROC_FS is not set

#
# SCSI support type (disk, tape, CD-ROM)
#
CONFIG_BLK_DEV_SD=y
# CONFIG_CHR_DEV_ST is not set
# CONFIG_CHR_DEV_OSST is not set
CONFIG_BLK_DEV_SR=y
CONFIG_BLK_DEV_SR_VENDOR=y
CONFIG_CHR_DEV_SG=y
# CONFIG_CHR_DEV_SCH is not set

#
# Some SCSI devices (e.g. CD jukebox) support multiple LUNs
#
# CONFIG_SCSI_MULTI_LUN is not set
CONFIG_SCSI_CONSTANTS=y
# CONFIG_SCSI_LOGGING is not set
# CONFIG_SCSI_SCAN_ASYNC is not set
CONFIG_SCSI_WAIT_SCAN=m

#
# SCSI Transports
#
CONFIG_SCSI_SPI_ATTRS=y
# CONFIG_SCSI_FC_ATTRS is not set
# CONFIG_SCSI_ISCSI_ATTRS is not set
CONFIG_SCSI_SAS_ATTRS=y
# CONFIG_SCSI_SAS_LIBSAS is not set
CONFIG_SCSI_LOWLEVEL=y
# CONFIG_ISCSI_TCP is not set
# CONFIG_BLK_DEV_3W_XXXX_RAID is not set
# CONFIG_SCSI_3W_9XXX is not set
# CONFIG_SCSI_ACARD is not set
# CONFIG_SCSI_AACRAID is not set
# CONFIG_SCSI_AIC7XXX is not set
# CONFIG_SCSI_AIC7XXX_OLD is not set
# CONFIG_SCSI_AIC79XX is not set
# CONFIG_SCSI_AIC94XX is not set
# CONFIG_SCSI_ARCMSR is not set
# CONFIG_MEGARAID_NEWGEN is not set
# CONFIG_MEGARAID_LEGACY is not set
# CONFIG_MEGARAID_SAS is not set
# CONFIG_SCSI_HPTIOP is not set
# CONFIG_SCSI_BUSLOGIC is not set
# CONFIG_SCSI_DMX3191D is not set
# CONFIG_SCSI_EATA is not set
# CONFIG_SCSI_FUTURE_DOMAIN is not set
# CONFIG_SCSI_GDTH is not set
# CONFIG_SCSI_IPS is not set
# CONFIG_SCSI_INITIO is not set
# CONFIG_SCSI_INIA100 is not set
# CONFIG_SCSI_PPA is not set
# CONFIG_SCSI_IMM is not set
# CONFIG_SCSI_STEX is not set
# CONFIG_SCSI_SYM53C8XX_2 is not set
# CONFIG_SCSI_IPR is not set
# CONFIG_SCSI_QLOGIC_1280 is not set
# CONFIG_SCSI_QLA_FC is not set
# CONFIG_SCSI_QLA_ISCSI is not set
# CONFIG_SCSI_LPFC is not set
# CONFIG_SCSI_DC395x is not set
# CONFIG_SCSI_DC390T is not set
# CONFIG_SCSI_DEBUG is not set
# CONFIG_SCSI_SRP is not set
CONFIG_ATA=y
# CONFIG_ATA_NONSTANDARD is not set
CONFIG_ATA_ACPI=y
CONFIG_SATA_AHCI=y
# CONFIG_SATA_SVW is not set
CONFIG_ATA_PIIX=y
# CONFIG_SATA_MV is not set
# CONFIG_SATA_NV is not set
# CONFIG_PDC_ADMA is not set
# CONFIG_SATA_QSTOR is not set
# CONFIG_SATA_PROMISE is not set
# CONFIG_SATA_SX4 is not set
# CONFIG_SATA_SIL is not set
# CONFIG_SATA_SIL24 is not set
# CONFIG_SATA_SIS is not set
# CONFIG_SATA_ULI is not set
# CONFIG_SATA_VIA is not set
# CONFIG_SATA_VITESSE is not set
# CONFIG_SATA_INIC162X is not set
# CONFIG_PATA_ALI is not set
# CONFIG_PATA_AMD is not set
# CONFIG_PATA_ARTOP is not set
# CONFIG_PATA_ATIIXP is not set
# CONFIG_PATA_CMD640_PCI is not set
# CONFIG_PATA_CMD64X is not set
# CONFIG_PATA_CS5520 is not set
# CONFIG_PATA_CS5530 is not set
# CONFIG_PATA_CYPRESS is not set
# CONFIG_PATA_EFAR is not set
# CONFIG_ATA_GENERIC is not set
# CONFIG_PATA_HPT366 is not set
# CONFIG_PATA_HPT37X is not set
# CONFIG_PATA_HPT3X2N is not set
# CONFIG_PATA_HPT3X3 is not set
# CONFIG_PATA_IT821X is not set
# CONFIG_PATA_IT8213 is not set
# CONFIG_PATA_JMICRON is not set
# CONFIG_PATA_TRIFLEX is not set
# CONFIG_PATA_MARVELL is not set
# CONFIG_PATA_MPIIX is not set
# CONFIG_PATA_OLDPIIX is not set
# CONFIG_PATA_NETCELL is not set
# CONFIG_PATA_NS87410 is not set
# CONFIG_PATA_OPTI is not set
# CONFIG_PATA_OPTIDMA is not set
# CONFIG_PATA_PDC_OLD is not set
# CONFIG_PATA_RADISYS is not set
# CONFIG_PATA_RZ1000 is not set
# CONFIG_PATA_SC1200 is not set
# CONFIG_PATA_SERVERWORKS is not set
# CONFIG_PATA_PDC2027X is not set
# CONFIG_PATA_SIL680 is not set
# CONFIG_PATA_SIS is not set
# CONFIG_PATA_VIA is not set
# CONFIG_PATA_WINBOND is not set
# CONFIG_PATA_PLATFORM is not set
# CONFIG_MD is not set

#
# Fusion MPT device support
#
# CONFIG_FUSION is not set
# CONFIG_FUSION_SPI is not set
# CONFIG_FUSION_FC is not set
# CONFIG_FUSION_SAS is not set

#
# IEEE 1394 (FireWire) support
#
# CONFIG_FIREWIRE is not set
# CONFIG_IEEE1394 is not set
# CONFIG_I2O is not set
# CONFIG_MACINTOSH_DRIVERS is not set
CONFIG_NETDEVICES=y
# CONFIG_NETDEVICES_MULTIQUEUE is not set
# CONFIG_DUMMY is not set
# CONFIG_BONDING is not set
# CONFIG_MACVLAN is not set
# CONFIG_EQUALIZER is not set
CONFIG_TUN=y
# CONFIG_NET_SB1000 is not set
# CONFIG_ARCNET is not set
# CONFIG_NET_ETHERNET is not set
CONFIG_NETDEV_1000=y
# CONFIG_ACENIC is not set
# CONFIG_DL2K is not set
CONFIG_E1000=y
CONFIG_E1000_NAPI=y
# CONFIG_E1000_DISABLE_PACKET_SPLIT is not set
# CONFIG_NS83820 is not set
# CONFIG_HAMACHI is not set
# CONFIG_YELLOWFIN is not set
# CONFIG_R8169 is not set
# CONFIG_SIS190 is not set
# CONFIG_SKGE is not set
# CONFIG_SKY2 is not set
# CONFIG_VIA_VELOCITY is not set
# CONFIG_TIGON3 is not set
# CONFIG_BNX2 is not set
# CONFIG_QLA3XXX is not set
# CONFIG_ATL1 is not set
# CONFIG_NETDEV_10000 is not set
# CONFIG_TR is not set

#
# Wireless LAN
#
# CONFIG_WLAN_PRE80211 is not set
CONFIG_WLAN_80211=y
# CONFIG_IPW2100 is not set
# CONFIG_IPW2200 is not set
# CONFIG_LIBERTAS is not set
# CONFIG_AIRO is not set
# CONFIG_HERMES is not set
# CONFIG_ATMEL is not set
# CONFIG_PRISM54 is not set
# CONFIG_USB_ZD1201 is not set
# CONFIG_HOSTAP is not set

#
# USB Network Adapters
#
# CONFIG_USB_CATC is not set
# CONFIG_USB_KAWETH is not set
# CONFIG_USB_PEGASUS is not set
# CONFIG_USB_RTL8150 is not set
# CONFIG_USB_USBNET_MII is not set
# CONFIG_USB_USBNET is not set
# CONFIG_WAN is not set
# CONFIG_FDDI is not set
# CONFIG_HIPPI is not set
# CONFIG_PLIP is not set
# CONFIG_PPP is not set
# CONFIG_SLIP is not set
# CONFIG_NET_FC is not set
# CONFIG_SHAPER is not set
# CONFIG_NETCONSOLE is not set
# CONFIG_NETPOLL is not set
# CONFIG_NET_POLL_CONTROLLER is not set
# CONFIG_ISDN is not set
# CONFIG_PHONE is not set

#
# Input device support
#
CONFIG_INPUT=y
# CONFIG_INPUT_FF_MEMLESS is not set
# CONFIG_INPUT_POLLDEV is not set

#
# Userland interfaces
#
CONFIG_INPUT_MOUSEDEV=y
# CONFIG_INPUT_MOUSEDEV_PSAUX is not set
CONFIG_INPUT_MOUSEDEV_SCREEN_X=1024
CONFIG_INPUT_MOUSEDEV_SCREEN_Y=768
# CONFIG_INPUT_JOYDEV is not set
# CONFIG_INPUT_TSDEV is not set
CONFIG_INPUT_EVDEV=y
# CONFIG_INPUT_EVBUG is not set

#
# Input Device Drivers
#
CONFIG_INPUT_KEYBOARD=y
CONFIG_KEYBOARD_ATKBD=y
# CONFIG_KEYBOARD_SUNKBD is not set
# CONFIG_KEYBOARD_LKKBD is not set
# CONFIG_KEYBOARD_XTKBD is not set
# CONFIG_KEYBOARD_NEWTON is not set
# CONFIG_KEYBOARD_STOWAWAY is not set
CONFIG_INPUT_MOUSE=y
CONFIG_MOUSE_PS2=y
# CONFIG_MOUSE_PS2_ALPS is not set
# CONFIG_MOUSE_PS2_LOGIPS2PP is not set
CONFIG_MOUSE_PS2_SYNAPTICS=y
# CONFIG_MOUSE_PS2_LIFEBOOK is not set
CONFIG_MOUSE_PS2_TRACKPOINT=y
# CONFIG_MOUSE_PS2_TOUCHKIT is not set
# CONFIG_MOUSE_SERIAL is not set
# CONFIG_MOUSE_APPLETOUCH is not set
# CONFIG_MOUSE_VSXXXAA is not set
# CONFIG_INPUT_JOYSTICK is not set
# CONFIG_INPUT_TABLET is not set
# CONFIG_INPUT_TOUCHSCREEN is not set
# CONFIG_INPUT_MISC is not set

#
# Hardware I/O ports
#
CONFIG_SERIO=y
CONFIG_SERIO_I8042=y
# CONFIG_SERIO_SERPORT is not set
# CONFIG_SERIO_CT82C710 is not set
# CONFIG_SERIO_PARKBD is not set
# CONFIG_SERIO_PCIPS2 is not set
CONFIG_SERIO_LIBPS2=y
# CONFIG_SERIO_RAW is not set
# CONFIG_GAMEPORT is not set

#
# Character devices
#
CONFIG_VT=y
CONFIG_VT_CONSOLE=y
CONFIG_HW_CONSOLE=y
CONFIG_VT_HW_CONSOLE_BINDING=y
# CONFIG_SERIAL_NONSTANDARD is not set

#
# Serial drivers
#
CONFIG_SERIAL_8250=y
CONFIG_SERIAL_8250_CONSOLE=y
CONFIG_FIX_EARLYCON_MEM=y
CONFIG_SERIAL_8250_PCI=y
CONFIG_SERIAL_8250_PNP=y
CONFIG_SERIAL_8250_NR_UARTS=4
CONFIG_SERIAL_8250_RUNTIME_UARTS=4
CONFIG_SERIAL_8250_EXTENDED=y
# CONFIG_SERIAL_8250_MANY_PORTS is not set
CONFIG_SERIAL_8250_SHARE_IRQ=y
# CONFIG_SERIAL_8250_DETECT_IRQ is not set
# CONFIG_SERIAL_8250_RSA is not set

#
# Non-8250 serial port support
#
CONFIG_SERIAL_CORE=y
CONFIG_SERIAL_CORE_CONSOLE=y
# CONFIG_SERIAL_JSM is not set
CONFIG_UNIX98_PTYS=y
# CONFIG_LEGACY_PTYS is not set
# CONFIG_PRINTER is not set
# CONFIG_PPDEV is not set
# CONFIG_TIPAR is not set
# CONFIG_IPMI_HANDLER is not set
# CONFIG_WATCHDOG is not set
CONFIG_HW_RANDOM=y
CONFIG_HW_RANDOM_INTEL=y
# CONFIG_HW_RANDOM_AMD is not set
CONFIG_NVRAM=y
CONFIG_RTC=y
# CONFIG_R3964 is not set
# CONFIG_APPLICOM is not set
CONFIG_AGP=y
# CONFIG_AGP_AMD64 is not set
CONFIG_AGP_INTEL=y
# CONFIG_AGP_SIS is not set
# CONFIG_AGP_VIA is not set
CONFIG_DRM=y
# CONFIG_DRM_TDFX is not set
# CONFIG_DRM_R128 is not set
# CONFIG_DRM_RADEON is not set
CONFIG_DRM_I810=y
# CONFIG_DRM_I830 is not set
CONFIG_DRM_I915=y
# CONFIG_DRM_MGA is not set
# CONFIG_DRM_SIS is not set
# CONFIG_DRM_VIA is not set
# CONFIG_DRM_SAVAGE is not set
# CONFIG_MWAVE is not set
# CONFIG_PC8736x_GPIO is not set
# CONFIG_RAW_DRIVER is not set
CONFIG_HPET=y
# CONFIG_HPET_RTC_IRQ is not set
CONFIG_HPET_MMAP=y
# CONFIG_HANGCHECK_TIMER is not set
# CONFIG_TCG_TPM is not set
# CONFIG_TELCLOCK is not set
CONFIG_DEVPORT=y
CONFIG_I2C=y
CONFIG_I2C_BOARDINFO=y
CONFIG_I2C_CHARDEV=y

#
# I2C Algorithms
#
CONFIG_I2C_ALGOBIT=y
CONFIG_I2C_ALGOPCF=y
CONFIG_I2C_ALGOPCA=y

#
# I2C Hardware Bus support
#
# CONFIG_I2C_ALI1535 is not set
# CONFIG_I2C_ALI1563 is not set
# CONFIG_I2C_ALI15X3 is not set
# CONFIG_I2C_AMD756 is not set
# CONFIG_I2C_AMD8111 is not set
CONFIG_I2C_I801=y
# CONFIG_I2C_I810 is not set
# CONFIG_I2C_PIIX4 is not set
# CONFIG_I2C_NFORCE2 is not set
# CONFIG_I2C_OCORES is not set
# CONFIG_I2C_PARPORT is not set
# CONFIG_I2C_PARPORT_LIGHT is not set
# CONFIG_I2C_PROSAVAGE is not set
# CONFIG_I2C_SAVAGE4 is not set
# CONFIG_I2C_SIMTEC is not set
# CONFIG_I2C_SIS5595 is not set
# CONFIG_I2C_SIS630 is not set
# CONFIG_I2C_SIS96X is not set
# CONFIG_I2C_TAOS_EVM is not set
# CONFIG_I2C_STUB is not set
# CONFIG_I2C_TINY_USB is not set
# CONFIG_I2C_VIA is not set
# CONFIG_I2C_VIAPRO is not set
# CONFIG_I2C_VOODOO3 is not set

#
# Miscellaneous I2C Chip support
#
# CONFIG_SENSORS_DS1337 is not set
# CONFIG_SENSORS_DS1374 is not set
# CONFIG_DS1682 is not set
CONFIG_SENSORS_EEPROM=y
CONFIG_SENSORS_PCF8574=y
# CONFIG_SENSORS_PCA9539 is not set
# CONFIG_SENSORS_PCF8591 is not set
# CONFIG_SENSORS_MAX6875 is not set
# CONFIG_SENSORS_TSL2550 is not set
# CONFIG_I2C_DEBUG_CORE is not set
# CONFIG_I2C_DEBUG_ALGO is not set
# CONFIG_I2C_DEBUG_BUS is not set
# CONFIG_I2C_DEBUG_CHIP is not set

#
# SPI support
#
# CONFIG_SPI is not set
# CONFIG_SPI_MASTER is not set
# CONFIG_W1 is not set
CONFIG_POWER_SUPPLY=y
# CONFIG_POWER_SUPPLY_DEBUG is not set
# CONFIG_PDA_POWER is not set
# CONFIG_BATTERY_DS2760 is not set
CONFIG_HWMON=y
# CONFIG_HWMON_VID is not set
# CONFIG_SENSORS_ABITUGURU is not set
# CONFIG_SENSORS_ABITUGURU3 is not set
# CONFIG_SENSORS_AD7418 is not set
# CONFIG_SENSORS_ADM1021 is not set
# CONFIG_SENSORS_ADM1025 is not set
# CONFIG_SENSORS_ADM1026 is not set
# CONFIG_SENSORS_ADM1029 is not set
# CONFIG_SENSORS_ADM1031 is not set
# CONFIG_SENSORS_ADM9240 is not set
# CONFIG_SENSORS_K8TEMP is not set
# CONFIG_SENSORS_ASB100 is not set
# CONFIG_SENSORS_ATXP1 is not set
# CONFIG_SENSORS_DS1621 is not set
# CONFIG_SENSORS_F71805F is not set
# CONFIG_SENSORS_FSCHER is not set
# CONFIG_SENSORS_FSCPOS is not set
# CONFIG_SENSORS_GL518SM is not set
# CONFIG_SENSORS_GL520SM is not set
CONFIG_SENSORS_CORETEMP=y
# CONFIG_SENSORS_IT87 is not set
# CONFIG_SENSORS_LM63 is not set
# CONFIG_SENSORS_LM75 is not set
# CONFIG_SENSORS_LM77 is not set
# CONFIG_SENSORS_LM78 is not set
# CONFIG_SENSORS_LM80 is not set
# CONFIG_SENSORS_LM83 is not set
# CONFIG_SENSORS_LM85 is not set
# CONFIG_SENSORS_LM87 is not set
# CONFIG_SENSORS_LM90 is not set
# CONFIG_SENSORS_LM92 is not set
# CONFIG_SENSORS_LM93 is not set
# CONFIG_SENSORS_MAX1619 is not set
# CONFIG_SENSORS_MAX6650 is not set
# CONFIG_SENSORS_PC87360 is not set
# CONFIG_SENSORS_PC87427 is not set
# CONFIG_SENSORS_SIS5595 is not set
# CONFIG_SENSORS_DME1737 is not set
# CONFIG_SENSORS_SMSC47M1 is not set
# CONFIG_SENSORS_SMSC47M192 is not set
# CONFIG_SENSORS_SMSC47B397 is not set
# CONFIG_SENSORS_VIA686A is not set
# CONFIG_SENSORS_VT1211 is not set
# CONFIG_SENSORS_VT8231 is not set
# CONFIG_SENSORS_W83781D is not set
# CONFIG_SENSORS_W83791D is not set
# CONFIG_SENSORS_W83792D is not set
# CONFIG_SENSORS_W83793 is not set
# CONFIG_SENSORS_W83L785TS is not set
# CONFIG_SENSORS_W83627HF is not set
# CONFIG_SENSORS_W83627EHF is not set
CONFIG_SENSORS_HDAPS=y
# CONFIG_SENSORS_APPLESMC is not set
# CONFIG_HWMON_DEBUG_CHIP is not set

#
# Multifunction device drivers
#
# CONFIG_MFD_SM501 is not set

#
# Multimedia devices
#
# CONFIG_VIDEO_DEV is not set
# CONFIG_DVB_CORE is not set
# CONFIG_DAB is not set

#
# Graphics support
#
CONFIG_BACKLIGHT_LCD_SUPPORT=y
CONFIG_LCD_CLASS_DEVICE=y
CONFIG_BACKLIGHT_CLASS_DEVICE=y
# CONFIG_BACKLIGHT_PROGEAR is not set

#
# Display device support
#
CONFIG_DISPLAY_SUPPORT=y

#
# Display hardware drivers
#
# CONFIG_VGASTATE is not set
CONFIG_VIDEO_OUTPUT_CONTROL=y
CONFIG_FB=y
CONFIG_FIRMWARE_EDID=y
# CONFIG_FB_DDC is not set
CONFIG_FB_CFB_FILLRECT=y
CONFIG_FB_CFB_COPYAREA=y
CONFIG_FB_CFB_IMAGEBLIT=y
# CONFIG_FB_SYS_FILLRECT is not set
# CONFIG_FB_SYS_COPYAREA is not set
# CONFIG_FB_SYS_IMAGEBLIT is not set
# CONFIG_FB_SYS_FOPS is not set
CONFIG_FB_DEFERRED_IO=y
# CONFIG_FB_SVGALIB is not set
# CONFIG_FB_MACMODES is not set
# CONFIG_FB_BACKLIGHT is not set
CONFIG_FB_MODE_HELPERS=y
CONFIG_FB_TILEBLITTING=y

#
# Frame buffer hardware drivers
#
# CONFIG_FB_CIRRUS is not set
# CONFIG_FB_PM2 is not set
# CONFIG_FB_CYBER2000 is not set
# CONFIG_FB_ARC is not set
# CONFIG_FB_ASILIANT is not set
# CONFIG_FB_IMSTT is not set
# CONFIG_FB_VGA16 is not set
CONFIG_FB_VESA=y
# CONFIG_FB_HECUBA is not set
# CONFIG_FB_HGA is not set
# CONFIG_FB_S1D13XXX is not set
# CONFIG_FB_NVIDIA is not set
# CONFIG_FB_RIVA is not set
# CONFIG_FB_LE80578 is not set
# CONFIG_FB_INTEL is not set
# CONFIG_FB_MATROX is not set
# CONFIG_FB_RADEON is not set
# CONFIG_FB_ATY128 is not set
# CONFIG_FB_ATY is not set
# CONFIG_FB_S3 is not set
# CONFIG_FB_SAVAGE is not set
# CONFIG_FB_SIS is not set
# CONFIG_FB_NEOMAGIC is not set
# CONFIG_FB_KYRO is not set
# CONFIG_FB_3DFX is not set
# CONFIG_FB_VOODOO1 is not set
# CONFIG_FB_VT8623 is not set
# CONFIG_FB_TRIDENT is not set
# CONFIG_FB_ARK is not set
# CONFIG_FB_PM3 is not set
# CONFIG_FB_GEODE is not set
# CONFIG_FB_VIRTUAL is not set

#
# Console display driver support
#
CONFIG_VGA_CONSOLE=y
CONFIG_VGACON_SOFT_SCROLLBACK=y
CONFIG_VGACON_SOFT_SCROLLBACK_SIZE=256
CONFIG_VIDEO_SELECT=y
CONFIG_DUMMY_CONSOLE=y
CONFIG_FRAMEBUFFER_CONSOLE=y
CONFIG_FRAMEBUFFER_CONSOLE_DETECT_PRIMARY=y
CONFIG_FRAMEBUFFER_CONSOLE_ROTATION=y
# CONFIG_FONTS is not set
CONFIG_FONT_8x8=y
CONFIG_FONT_8x16=y
# CONFIG_LOGO is not set

#
# Sound
#
CONFIG_SOUND=y

#
# Advanced Linux Sound Architecture
#
CONFIG_SND=y
CONFIG_SND_TIMER=y
CONFIG_SND_PCM=y
CONFIG_SND_RAWMIDI=y
CONFIG_SND_SEQUENCER=y
# CONFIG_SND_SEQ_DUMMY is not set
CONFIG_SND_OSSEMUL=y
CONFIG_SND_MIXER_OSS=y
CONFIG_SND_PCM_OSS=y
CONFIG_SND_PCM_OSS_PLUGINS=y
CONFIG_SND_SEQUENCER_OSS=y
CONFIG_SND_RTCTIMER=y
CONFIG_SND_SEQ_RTCTIMER_DEFAULT=y
CONFIG_SND_DYNAMIC_MINORS=y
# CONFIG_SND_SUPPORT_OLD_API is not set
# CONFIG_SND_VERBOSE_PROCFS is not set
# CONFIG_SND_VERBOSE_PRINTK is not set
# CONFIG_SND_DEBUG is not set

#
# Generic devices
#
CONFIG_SND_MPU401_UART=y
# CONFIG_SND_DUMMY is not set
# CONFIG_SND_VIRMIDI is not set
# CONFIG_SND_MTPAV is not set
# CONFIG_SND_MTS64 is not set
# CONFIG_SND_SERIAL_U16550 is not set
CONFIG_SND_MPU401=y
# CONFIG_SND_PORTMAN2X4 is not set

#
# PCI devices
#
# CONFIG_SND_AD1889 is not set
# CONFIG_SND_ALS300 is not set
# CONFIG_SND_ALS4000 is not set
# CONFIG_SND_ALI5451 is not set
# CONFIG_SND_ATIIXP is not set
# CONFIG_SND_ATIIXP_MODEM is not set
# CONFIG_SND_AU8810 is not set
# CONFIG_SND_AU8820 is not set
# CONFIG_SND_AU8830 is not set
# CONFIG_SND_AZT3328 is not set
# CONFIG_SND_BT87X is not set
# CONFIG_SND_CA0106 is not set
# CONFIG_SND_CMIPCI is not set
# CONFIG_SND_CS4281 is not set
# CONFIG_SND_CS46XX is not set
# CONFIG_SND_CS5530 is not set
# CONFIG_SND_DARLA20 is not set
# CONFIG_SND_GINA20 is not set
# CONFIG_SND_LAYLA20 is not set
# CONFIG_SND_DARLA24 is not set
# CONFIG_SND_GINA24 is not set
# CONFIG_SND_LAYLA24 is not set
# CONFIG_SND_MONA is not set
# CONFIG_SND_MIA is not set
# CONFIG_SND_ECHO3G is not set
# CONFIG_SND_INDIGO is not set
# CONFIG_SND_INDIGOIO is not set
# CONFIG_SND_INDIGODJ is not set
# CONFIG_SND_EMU10K1 is not set
# CONFIG_SND_EMU10K1X is not set
# CONFIG_SND_ENS1370 is not set
# CONFIG_SND_ENS1371 is not set
# CONFIG_SND_ES1938 is not set
# CONFIG_SND_ES1968 is not set
# CONFIG_SND_FM801 is not set
CONFIG_SND_HDA_INTEL=y
# CONFIG_SND_HDSP is not set
# CONFIG_SND_HDSPM is not set
# CONFIG_SND_ICE1712 is not set
# CONFIG_SND_ICE1724 is not set
# CONFIG_SND_INTEL8X0 is not set
# CONFIG_SND_INTEL8X0M is not set
# CONFIG_SND_KORG1212 is not set
# CONFIG_SND_MAESTRO3 is not set
# CONFIG_SND_MIXART is not set
# CONFIG_SND_NM256 is not set
# CONFIG_SND_PCXHR is not set
# CONFIG_SND_RIPTIDE is not set
# CONFIG_SND_RME32 is not set
# CONFIG_SND_RME96 is not set
# CONFIG_SND_RME9652 is not set
# CONFIG_SND_SONICVIBES is not set
# CONFIG_SND_TRIDENT is not set
# CONFIG_SND_VIA82XX is not set
# CONFIG_SND_VIA82XX_MODEM is not set
# CONFIG_SND_VX222 is not set
# CONFIG_SND_YMFPCI is not set

#
# USB devices
#
# CONFIG_SND_USB_AUDIO is not set
# CONFIG_SND_USB_USX2Y is not set
# CONFIG_SND_USB_CAIAQ is not set

#
# System on Chip audio support
#
# CONFIG_SND_SOC is not set

#
# SoC Audio support for SuperH
#

#
# Open Sound System
#
# CONFIG_SOUND_PRIME is not set
CONFIG_HID_SUPPORT=y
CONFIG_HID=y
# CONFIG_HID_DEBUG is not set

#
# USB Input Devices
#
CONFIG_USB_HID=y
# CONFIG_USB_HIDINPUT_POWERBOOK is not set
# CONFIG_HID_FF is not set
# CONFIG_USB_HIDDEV is not set
CONFIG_USB_SUPPORT=y
CONFIG_USB_ARCH_HAS_HCD=y
CONFIG_USB_ARCH_HAS_OHCI=y
CONFIG_USB_ARCH_HAS_EHCI=y
CONFIG_USB=y
# CONFIG_USB_DEBUG is not set

#
# Miscellaneous USB options
#
# CONFIG_USB_DEVICEFS is not set
# CONFIG_USB_DEVICE_CLASS is not set
CONFIG_USB_DYNAMIC_MINORS=y
# CONFIG_USB_SUSPEND is not set
# CONFIG_USB_PERSIST is not set
# CONFIG_USB_OTG is not set

#
# USB Host Controller Drivers
#
CONFIG_USB_EHCI_HCD=y
CONFIG_USB_EHCI_SPLIT_ISO=y
CONFIG_USB_EHCI_ROOT_HUB_TT=y
CONFIG_USB_EHCI_TT_NEWSCHED=y
# CONFIG_USB_ISP116X_HCD is not set
# CONFIG_USB_OHCI_HCD is not set
CONFIG_USB_UHCI_HCD=y
# CONFIG_USB_SL811_HCD is not set
# CONFIG_USB_R8A66597_HCD is not set

#
# USB Device Class drivers
#
CONFIG_USB_ACM=y
CONFIG_USB_PRINTER=y

#
# NOTE: USB_STORAGE enables SCSI, and 'SCSI disk support'
#

#
# may also be needed; see USB_STORAGE Help for more information
#
CONFIG_USB_STORAGE=y
# CONFIG_USB_STORAGE_DEBUG is not set
# CONFIG_USB_STORAGE_DATAFAB is not set
# CONFIG_USB_STORAGE_FREECOM is not set
# CONFIG_USB_STORAGE_DPCM is not set
# CONFIG_USB_STORAGE_USBAT is not set
# CONFIG_USB_STORAGE_SDDR09 is not set
# CONFIG_USB_STORAGE_SDDR55 is not set
# CONFIG_USB_STORAGE_JUMPSHOT is not set
# CONFIG_USB_STORAGE_ALAUDA is not set
# CONFIG_USB_STORAGE_KARMA is not set
# CONFIG_USB_LIBUSUAL is not set

#
# USB Imaging devices
#
# CONFIG_USB_MDC800 is not set
# CONFIG_USB_MICROTEK is not set
CONFIG_USB_MON=y

#
# USB port drivers
#
# CONFIG_USB_USS720 is not set

#
# USB Serial Converter support
#
# CONFIG_USB_SERIAL is not set

#
# USB Miscellaneous drivers
#
# CONFIG_USB_EMI62 is not set
# CONFIG_USB_EMI26 is not set
# CONFIG_USB_ADUTUX is not set
# CONFIG_USB_AUERSWALD is not set
# CONFIG_USB_RIO500 is not set
# CONFIG_USB_LEGOTOWER is not set
# CONFIG_USB_LCD is not set
# CONFIG_USB_BERRY_CHARGE is not set
# CONFIG_USB_LED is not set
# CONFIG_USB_CYPRESS_CY7C63 is not set
# CONFIG_USB_CYTHERM is not set
# CONFIG_USB_PHIDGET is not set
# CONFIG_USB_IDMOUSE is not set
# CONFIG_USB_FTDI_ELAN is not set
# CONFIG_USB_APPLEDISPLAY is not set
# CONFIG_USB_SISUSBVGA is not set
# CONFIG_USB_LD is not set
# CONFIG_USB_TRANCEVIBRATOR is not set
# CONFIG_USB_IOWARRIOR is not set

#
# USB DSL modem support
#

#
# USB Gadget Support
#
# CONFIG_USB_GADGET is not set
# CONFIG_MMC is not set
CONFIG_NEW_LEDS=y
CONFIG_LEDS_CLASS=y

#
# LED drivers
#

#
# LED Triggers
#
# CONFIG_LEDS_TRIGGERS is not set
# CONFIG_INFINIBAND is not set
# CONFIG_EDAC is not set

#
# Real Time Clock
#
# CONFIG_RTC_CLASS is not set

#
# DMA Engine support
#
# CONFIG_DMA_ENGINE is not set

#
# DMA Clients
#

#
# DMA Devices
#
CONFIG_AUXDISPLAY=y
# CONFIG_KS0108 is not set
# CONFIG_VIRTUALIZATION is not set

#
# Userspace I/O
#
# CONFIG_UIO is not set

#
# Firmware Drivers
#
CONFIG_EDD=y
# CONFIG_DELL_RBU is not set
# CONFIG_DCDBAS is not set
CONFIG_DMIID=y

#
# File systems
#
CONFIG_EXT2_FS=y
CONFIG_EXT2_FS_XATTR=y
CONFIG_EXT2_FS_POSIX_ACL=y
# CONFIG_EXT2_FS_SECURITY is not set
# CONFIG_EXT2_FS_XIP is not set
CONFIG_EXT3_FS=y
CONFIG_EXT3_FS_XATTR=y
CONFIG_EXT3_FS_POSIX_ACL=y
# CONFIG_EXT3_FS_SECURITY is not set
# CONFIG_EXT4DEV_FS is not set
CONFIG_JBD=y
# CONFIG_JBD_DEBUG is not set
CONFIG_FS_MBCACHE=y
CONFIG_REISERFS_FS=y
# CONFIG_REISERFS_CHECK is not set
# CONFIG_REISERFS_PROC_INFO is not set
CONFIG_REISERFS_FS_XATTR=y
CONFIG_REISERFS_FS_POSIX_ACL=y
# CONFIG_REISERFS_FS_SECURITY is not set
# CONFIG_JFS_FS is not set
CONFIG_FS_POSIX_ACL=y
# CONFIG_XFS_FS is not set
# CONFIG_GFS2_FS is not set
# CONFIG_OCFS2_FS is not set
# CONFIG_MINIX_FS is not set
# CONFIG_ROMFS_FS is not set
CONFIG_INOTIFY=y
CONFIG_INOTIFY_USER=y
# CONFIG_QUOTA is not set
# CONFIG_DNOTIFY is not set
# CONFIG_AUTOFS_FS is not set
CONFIG_AUTOFS4_FS=y
# CONFIG_FUSE_FS is not set
CONFIG_GENERIC_ACL=y

#
# CD-ROM/DVD Filesystems
#
CONFIG_ISO9660_FS=y
CONFIG_JOLIET=y
CONFIG_ZISOFS=y
CONFIG_UDF_FS=y
CONFIG_UDF_NLS=y

#
# DOS/FAT/NT Filesystems
#
CONFIG_FAT_FS=y
CONFIG_MSDOS_FS=y
CONFIG_VFAT_FS=y
CONFIG_FAT_DEFAULT_CODEPAGE=437
CONFIG_FAT_DEFAULT_IOCHARSET="iso8859-1"
# CONFIG_NTFS_FS is not set

#
# Pseudo filesystems
#
CONFIG_PROC_FS=y
CONFIG_PROC_KCORE=y
CONFIG_PROC_VMCORE=y
CONFIG_PROC_SYSCTL=y
CONFIG_SYSFS=y
CONFIG_TMPFS=y
CONFIG_TMPFS_POSIX_ACL=y
CONFIG_HUGETLBFS=y
CONFIG_HUGETLB_PAGE=y
CONFIG_RAMFS=y
# CONFIG_CONFIGFS_FS is not set

#
# Miscellaneous filesystems
#
# CONFIG_ADFS_FS is not set
# CONFIG_AFFS_FS is not set
# CONFIG_HFS_FS is not set
# CONFIG_HFSPLUS_FS is not set
# CONFIG_BEFS_FS is not set
# CONFIG_BFS_FS is not set
# CONFIG_EFS_FS is not set
# CONFIG_CRAMFS is not set
# CONFIG_VXFS_FS is not set
# CONFIG_HPFS_FS is not set
# CONFIG_QNX4FS_FS is not set
# CONFIG_SYSV_FS is not set
# CONFIG_UFS_FS is not set

#
# Network File Systems
#
CONFIG_NFS_FS=y
CONFIG_NFS_V3=y
CONFIG_NFS_V3_ACL=y
CONFIG_NFS_V4=y
CONFIG_NFS_DIRECTIO=y
# CONFIG_NFSD is not set
CONFIG_LOCKD=y
CONFIG_LOCKD_V4=y
CONFIG_NFS_ACL_SUPPORT=y
CONFIG_NFS_COMMON=y
CONFIG_SUNRPC=y
CONFIG_SUNRPC_GSS=y
# CONFIG_SUNRPC_BIND34 is not set
CONFIG_RPCSEC_GSS_KRB5=y
# CONFIG_RPCSEC_GSS_SPKM3 is not set
# CONFIG_SMB_FS is not set
# CONFIG_CIFS is not set
# CONFIG_NCP_FS is not set
# CONFIG_CODA_FS is not set
# CONFIG_AFS_FS is not set

#
# Partition Types
#
# CONFIG_PARTITION_ADVANCED is not set
CONFIG_MSDOS_PARTITION=y

#
# Native Language Support
#
CONFIG_NLS=y
CONFIG_NLS_DEFAULT="iso8859-1"
CONFIG_NLS_CODEPAGE_437=y
# CONFIG_NLS_CODEPAGE_737 is not set
# CONFIG_NLS_CODEPAGE_775 is not set
# CONFIG_NLS_CODEPAGE_850 is not set
# CONFIG_NLS_CODEPAGE_852 is not set
# CONFIG_NLS_CODEPAGE_855 is not set
# CONFIG_NLS_CODEPAGE_857 is not set
# CONFIG_NLS_CODEPAGE_860 is not set
# CONFIG_NLS_CODEPAGE_861 is not set
# CONFIG_NLS_CODEPAGE_862 is not set
# CONFIG_NLS_CODEPAGE_863 is not set
# CONFIG_NLS_CODEPAGE_864 is not set
# CONFIG_NLS_CODEPAGE_865 is not set
# CONFIG_NLS_CODEPAGE_866 is not set
# CONFIG_NLS_CODEPAGE_869 is not set
# CONFIG_NLS_CODEPAGE_936 is not set
# CONFIG_NLS_CODEPAGE_950 is not set
# CONFIG_NLS_CODEPAGE_932 is not set
# CONFIG_NLS_CODEPAGE_949 is not set
# CONFIG_NLS_CODEPAGE_874 is not set
# CONFIG_NLS_ISO8859_8 is not set
# CONFIG_NLS_CODEPAGE_1250 is not set
# CONFIG_NLS_CODEPAGE_1251 is not set
CONFIG_NLS_ASCII=y
CONFIG_NLS_ISO8859_1=y
# CONFIG_NLS_ISO8859_2 is not set
# CONFIG_NLS_ISO8859_3 is not set
# CONFIG_NLS_ISO8859_4 is not set
# CONFIG_NLS_ISO8859_5 is not set
# CONFIG_NLS_ISO8859_6 is not set
# CONFIG_NLS_ISO8859_7 is not set
# CONFIG_NLS_ISO8859_9 is not set
# CONFIG_NLS_ISO8859_13 is not set
# CONFIG_NLS_ISO8859_14 is not set
CONFIG_NLS_ISO8859_15=y
# CONFIG_NLS_KOI8_R is not set
# CONFIG_NLS_KOI8_U is not set
CONFIG_NLS_UTF8=y

#
# Distributed Lock Manager
#
# CONFIG_DLM is not set

#
# Instrumentation Support
#
CONFIG_PROFILING=y
CONFIG_OPROFILE=y
# CONFIG_KPROBES is not set

#
# Kernel hacking
#
CONFIG_TRACE_IRQFLAGS_SUPPORT=y
# CONFIG_PRINTK_TIME is not set
# CONFIG_ENABLE_MUST_CHECK is not set
CONFIG_MAGIC_SYSRQ=y
# CONFIG_UNUSED_SYMBOLS is not set
# CONFIG_DEBUG_FS is not set
# CONFIG_HEADERS_CHECK is not set
# CONFIG_DEBUG_KERNEL is not set
# CONFIG_DEBUG_BUGVERBOSE is not set

#
# Security options
#
# CONFIG_KEYS is not set
# CONFIG_SECURITY is not set
CONFIG_CRYPTO=y
CONFIG_CRYPTO_ALGAPI=y
CONFIG_CRYPTO_BLKCIPHER=y
CONFIG_CRYPTO_MANAGER=y
# CONFIG_CRYPTO_HMAC is not set
# CONFIG_CRYPTO_XCBC is not set
# CONFIG_CRYPTO_NULL is not set
# CONFIG_CRYPTO_MD4 is not set
CONFIG_CRYPTO_MD5=y
# CONFIG_CRYPTO_SHA1 is not set
# CONFIG_CRYPTO_SHA256 is not set
# CONFIG_CRYPTO_SHA512 is not set
# CONFIG_CRYPTO_WP512 is not set
# CONFIG_CRYPTO_TGR192 is not set
# CONFIG_CRYPTO_GF128MUL is not set
# CONFIG_CRYPTO_ECB is not set
CONFIG_CRYPTO_CBC=y
# CONFIG_CRYPTO_PCBC is not set
# CONFIG_CRYPTO_LRW is not set
# CONFIG_CRYPTO_CRYPTD is not set
CONFIG_CRYPTO_DES=y
# CONFIG_CRYPTO_FCRYPT is not set
# CONFIG_CRYPTO_BLOWFISH is not set
# CONFIG_CRYPTO_TWOFISH is not set
# CONFIG_CRYPTO_TWOFISH_X86_64 is not set
# CONFIG_CRYPTO_SERPENT is not set
# CONFIG_CRYPTO_AES is not set
# CONFIG_CRYPTO_AES_X86_64 is not set
# CONFIG_CRYPTO_CAST5 is not set
# CONFIG_CRYPTO_CAST6 is not set
# CONFIG_CRYPTO_TEA is not set
# CONFIG_CRYPTO_ARC4 is not set
# CONFIG_CRYPTO_KHAZAD is not set
# CONFIG_CRYPTO_ANUBIS is not set
CONFIG_CRYPTO_DEFLATE=y
# CONFIG_CRYPTO_MICHAEL_MIC is not set
# CONFIG_CRYPTO_CRC32C is not set
# CONFIG_CRYPTO_CAMELLIA is not set
# CONFIG_CRYPTO_TEST is not set
# CONFIG_CRYPTO_HW is not set

#
# Library routines
#
CONFIG_BITREVERSE=y
# CONFIG_CRC_CCITT is not set
# CONFIG_CRC16 is not set
# CONFIG_CRC_ITU_T is not set
CONFIG_CRC32=y
# CONFIG_CRC7 is not set
# CONFIG_LIBCRC32C is not set
CONFIG_ZLIB_INFLATE=y
CONFIG_ZLIB_DEFLATE=y
CONFIG_PLIST=y
CONFIG_HAS_IOMEM=y
CONFIG_HAS_IOPORT=y
CONFIG_HAS_DMA=y

Re: lmbench ctxsw regression with CFS

[Ingo Molnar]

* Nick Piggin <npiggin@suse.de> wrote:

> > > > One thing to check out is whether the lmbench numbers are 
> > > > "correct". Especially on SMP systems, the lmbench numbers are 
> > > > actually *best* when the two processes run on the same CPU, even 
> > > > though that's not really at all the best scheduling - it's just 
> > > > that it artificially improves lmbench numbers because of the 
> > > > close cache affinity for the pipe data structures.
> > > 
> > > Yes, I bound them to a single core.
> > 
> > could you send me the .config you used?
> 
> Sure, attached...
> 
> You don't see a regression? If not, then can you send me the .config 
> you used? [...]

i used your config to get a few numbers and to see what happens. Here's 
the numbers of 10 consecutive "lat_ctx -s 0 2" runs:

                        [ time in micro-seconds, smaller is better ]

        v2.6.22         v2.6.23-git          v2.6.23-git+const-param
        -------         -----------          -----------------------
         1.30              1.60                       1.19
         1.30              1.36                       1.18
         1.14              1.50                       1.01
         1.26              1.27                       1.23
         1.22              1.40                       1.04
         1.13              1.34                       1.09
         1.27              1.39                       1.05
         1.20              1.30                       1.16
         1.20              1.17                       1.16
         1.25              1.33                       1.01
       -------------------------------------------------------------
  avg:   1.22              1.36 (+11.3%)              1.11 (-10.3%)
  min:   1.13              1.17 ( +3.5%)              1.01 (-11.8%)
  max:   1.27              1.60 (+26.0%)              1.23 ( -3.2%)

one reason for the extra overhead is the current tunability of CFS, but 
that is not fundamental, it's caused by the many knobs that CFS has at 
the moment. The const-tuning patch (attached below, results in the 
rightmost column) changes those knobs to constants, allowing the 
compiler to optimize the math better and reduce code size. (the code 
movement in the patch makes up for most of its size, the change that it 
does is simple otherwise.)

so CFS can be faster at micro-context-switching than 2.6.22. But, at 
this point i'd also like to warn against putting _too_ much emphasis on 
lat_ctx numbers in general. lat_ctx prints a 'derived' micro-benchmark 
number. It uses a pair of pipes to context-switch between tasks but only 
prints the delta overhead that context-switching causes. The 'full' 
latency of the pipe operations can be seen via the following pipe-test.c 
code:

   http://redhat.com/~mingo/cfs-scheduler/tools/pipe-test.c

run it to see the full cost:

   neptune:~> ./pipe-test
   4.67 usecs/loop.
   4.41 usecs/loop.
   4.46 usecs/loop.
   4.46 usecs/loop.
   4.44 usecs/loop.
   4.41 usecs/loop.

so the _full_ cost, of even this micro-benchmark, is 4-5 microseconds, 
not 1 microsecond. So even this artificial micro-benchmark sees an 
actual slowdown of only 2.8%.

if you check a macro-benchmark like "hackbench 50":

         [ time in seconds, smaller is better ]

         v2.6.22              v2.6.23-cfs
         -------              -----------
          3.019                  2.842
          2.994                  2.878
          2.977                  2.882
          3.012                  2.864
          2.996                  2.882

then the difference is even starker because with CFS the _quality_ of 
scheduling decisions has increased. So even if we had increased 
micro-costs (which we wont have once the current tuning period is over 
and we cast the CFS parameters into constants), the quality of 
macro-scheduling can offset that, and not only on the desktop!

so that's why our main focus in CFS was on the macro-properties of 
scheduling _first_, and then the micro-properties are adjusted to the 
macro-constraints as a second layer.

	Ingo

----------------------------->
---
 include/linux/sched.h |    2 
 kernel/sched.c        |  143 +++++++++++++++++++++++++-------------------------
 kernel/sched_fair.c   |   27 +++++----
 kernel/sched_rt.c     |   10 ---
 4 files changed, 92 insertions(+), 90 deletions(-)

Index: linux/include/linux/sched.h
===================================================================
--- linux.orig/include/linux/sched.h
+++ linux/include/linux/sched.h
@@ -1396,6 +1396,7 @@ static inline void idle_task_exit(void) 
 
 extern void sched_idle_next(void);
 
+#ifdef CONFIG_SCHED_DEBUG
 extern unsigned int sysctl_sched_granularity;
 extern unsigned int sysctl_sched_wakeup_granularity;
 extern unsigned int sysctl_sched_batch_wakeup_granularity;
@@ -1403,6 +1404,7 @@ extern unsigned int sysctl_sched_stat_gr
 extern unsigned int sysctl_sched_runtime_limit;
 extern unsigned int sysctl_sched_child_runs_first;
 extern unsigned int sysctl_sched_features;
+#endif
 
 #ifdef CONFIG_RT_MUTEXES
 extern int rt_mutex_getprio(struct task_struct *p);
Index: linux/kernel/sched.c
===================================================================
--- linux.orig/kernel/sched.c
+++ linux/kernel/sched.c
@@ -657,7 +657,7 @@ calc_delta_mine(unsigned long delta_exec
 		tmp = (tmp * lw->inv_weight) >> WMULT_SHIFT;
 	}
 
-	return (unsigned long)min(tmp, (u64)sysctl_sched_runtime_limit);
+	return (unsigned long)min(tmp, (u64)ULONG_MAX);
 }
 
 static inline unsigned long
@@ -678,46 +678,6 @@ static void update_load_sub(struct load_
 	lw->inv_weight = 0;
 }
 
-static void __update_curr_load(struct rq *rq, struct load_stat *ls)
-{
-	if (rq->curr != rq->idle && ls->load.weight) {
-		ls->delta_exec += ls->delta_stat;
-		ls->delta_fair += calc_delta_fair(ls->delta_stat, &ls->load);
-		ls->delta_stat = 0;
-	}
-}
-
-/*
- * Update delta_exec, delta_fair fields for rq.
- *
- * delta_fair clock advances at a rate inversely proportional to
- * total load (rq->ls.load.weight) on the runqueue, while
- * delta_exec advances at the same rate as wall-clock (provided
- * cpu is not idle).
- *
- * delta_exec / delta_fair is a measure of the (smoothened) load on this
- * runqueue over any given interval. This (smoothened) load is used
- * during load balance.
- *
- * This function is called /before/ updating rq->ls.load
- * and when switching tasks.
- */
-static void update_curr_load(struct rq *rq, u64 now)
-{
-	struct load_stat *ls = &rq->ls;
-	u64 start;
-
-	start = ls->load_update_start;
-	ls->load_update_start = now;
-	ls->delta_stat += now - start;
-	/*
-	 * Stagger updates to ls->delta_fair. Very frequent updates
-	 * can be expensive.
-	 */
-	if (ls->delta_stat >= sysctl_sched_stat_granularity)
-		__update_curr_load(rq, ls);
-}
-
 /*
  * To aid in avoiding the subversion of "niceness" due to uneven distribution
  * of tasks with abnormal "nice" values across CPUs the contribution that
@@ -781,32 +741,6 @@ static const u32 prio_to_wmult[40] = {
 /*  15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
 };
 
-static inline void
-inc_load(struct rq *rq, const struct task_struct *p, u64 now)
-{
-	update_curr_load(rq, now);
-	update_load_add(&rq->ls.load, p->se.load.weight);
-}
-
-static inline void
-dec_load(struct rq *rq, const struct task_struct *p, u64 now)
-{
-	update_curr_load(rq, now);
-	update_load_sub(&rq->ls.load, p->se.load.weight);
-}
-
-static inline void inc_nr_running(struct task_struct *p, struct rq *rq, u64 now)
-{
-	rq->nr_running++;
-	inc_load(rq, p, now);
-}
-
-static inline void dec_nr_running(struct task_struct *p, struct rq *rq, u64 now)
-{
-	rq->nr_running--;
-	dec_load(rq, p, now);
-}
-
 static void activate_task(struct rq *rq, struct task_struct *p, int wakeup);
 
 /*
@@ -837,6 +771,72 @@ static int balance_tasks(struct rq *this
 
 #define sched_class_highest (&rt_sched_class)
 
+static void __update_curr_load(struct rq *rq, struct load_stat *ls)
+{
+	if (rq->curr != rq->idle && ls->load.weight) {
+		ls->delta_exec += ls->delta_stat;
+		ls->delta_fair += calc_delta_fair(ls->delta_stat, &ls->load);
+		ls->delta_stat = 0;
+	}
+}
+
+/*
+ * Update delta_exec, delta_fair fields for rq.
+ *
+ * delta_fair clock advances at a rate inversely proportional to
+ * total load (rq->ls.load.weight) on the runqueue, while
+ * delta_exec advances at the same rate as wall-clock (provided
+ * cpu is not idle).
+ *
+ * delta_exec / delta_fair is a measure of the (smoothened) load on this
+ * runqueue over any given interval. This (smoothened) load is used
+ * during load balance.
+ *
+ * This function is called /before/ updating rq->ls.load
+ * and when switching tasks.
+ */
+static void update_curr_load(struct rq *rq, u64 now)
+{
+	struct load_stat *ls = &rq->ls;
+	u64 start;
+
+	start = ls->load_update_start;
+	ls->load_update_start = now;
+	ls->delta_stat += now - start;
+	/*
+	 * Stagger updates to ls->delta_fair. Very frequent updates
+	 * can be expensive.
+	 */
+	if (ls->delta_stat >= sysctl_sched_stat_granularity)
+		__update_curr_load(rq, ls);
+}
+
+static inline void
+inc_load(struct rq *rq, const struct task_struct *p, u64 now)
+{
+	update_curr_load(rq, now);
+	update_load_add(&rq->ls.load, p->se.load.weight);
+}
+
+static inline void
+dec_load(struct rq *rq, const struct task_struct *p, u64 now)
+{
+	update_curr_load(rq, now);
+	update_load_sub(&rq->ls.load, p->se.load.weight);
+}
+
+static inline void inc_nr_running(struct task_struct *p, struct rq *rq, u64 now)
+{
+	rq->nr_running++;
+	inc_load(rq, p, now);
+}
+
+static inline void dec_nr_running(struct task_struct *p, struct rq *rq, u64 now)
+{
+	rq->nr_running--;
+	dec_load(rq, p, now);
+}
+
 static void set_load_weight(struct task_struct *p)
 {
 	task_rq(p)->cfs.wait_runtime -= p->se.wait_runtime;
@@ -1661,8 +1661,10 @@ void fastcall wake_up_new_task(struct ta
 
 	p->prio = effective_prio(p);
 
-	if (!sysctl_sched_child_runs_first || (clone_flags & CLONE_VM) ||
-			task_cpu(p) != this_cpu || !current->se.on_rq) {
+	if (!p->sched_class->task_new || !sysctl_sched_child_runs_first ||
+			(clone_flags & CLONE_VM) || task_cpu(p) != this_cpu ||
+			!current->se.on_rq) {
+
 		activate_task(rq, p, 0);
 	} else {
 		/*
@@ -1670,6 +1672,7 @@ void fastcall wake_up_new_task(struct ta
 		 * management (if any):
 		 */
 		p->sched_class->task_new(rq, p);
+		inc_nr_running(p, rq, rq_clock(rq));
 	}
 	check_preempt_curr(rq, p);
 	task_rq_unlock(rq, &flags);
@@ -4864,6 +4867,7 @@ cpumask_t nohz_cpu_mask = CPU_MASK_NONE;
  */
 static inline void sched_init_granularity(void)
 {
+#ifdef CONFIG_SCHED_DEBUG
 	unsigned int factor = 1 + ilog2(num_online_cpus());
 	const unsigned long gran_limit = 100000000;
 
@@ -4873,6 +4877,7 @@ static inline void sched_init_granularit
 
 	sysctl_sched_runtime_limit = sysctl_sched_granularity * 4;
 	sysctl_sched_wakeup_granularity = sysctl_sched_granularity / 2;
+#endif
 }
 
 #ifdef CONFIG_SMP
Index: linux/kernel/sched_fair.c
===================================================================
--- linux.orig/kernel/sched_fair.c
+++ linux/kernel/sched_fair.c
@@ -18,6 +18,15 @@
  */
 
 /*
+ * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
+ */
+#ifdef CONFIG_SCHED_DEBUG
+# define const_debug __read_mostly
+#else
+# define const_debug static const
+#endif
+
+/*
  * Preemption granularity:
  * (default: 2 msec, units: nanoseconds)
  *
@@ -31,7 +40,7 @@
  * number of CPUs. (i.e. factor 2x on 2-way systems, 3x on 4-way
  * systems, 4x on 8-way systems, 5x on 16-way systems, etc.)
  */
-unsigned int sysctl_sched_granularity __read_mostly = 2000000000ULL/HZ;
+const_debug unsigned int sysctl_sched_granularity = 2000000000ULL/HZ;
 
 /*
  * SCHED_BATCH wake-up granularity.
@@ -41,8 +50,8 @@ unsigned int sysctl_sched_granularity __
  * and reduces their over-scheduling. Synchronous workloads will still
  * have immediate wakeup/sleep latencies.
  */
-unsigned int sysctl_sched_batch_wakeup_granularity __read_mostly =
-							10000000000ULL/HZ;
+const_debug unsigned int
+sysctl_sched_batch_wakeup_granularity = 10000000000ULL/HZ;
 
 /*
  * SCHED_OTHER wake-up granularity.
@@ -52,14 +61,11 @@ unsigned int sysctl_sched_batch_wakeup_g
  * and reduces their over-scheduling. Synchronous workloads will still
  * have immediate wakeup/sleep latencies.
  */
-unsigned int sysctl_sched_wakeup_granularity __read_mostly = 1000000000ULL/HZ;
+const_debug unsigned int sysctl_sched_wakeup_granularity = 1000000000ULL/HZ;
 
-unsigned int sysctl_sched_stat_granularity __read_mostly;
+const_debug unsigned int sysctl_sched_stat_granularity;
 
-/*
- * Initialized in sched_init_granularity():
- */
-unsigned int sysctl_sched_runtime_limit __read_mostly;
+const_debug unsigned int sysctl_sched_runtime_limit = 4000000000ULL/HZ;
 
 /*
  * Debugging: various feature bits
@@ -73,7 +79,7 @@ enum {
 	SCHED_FEAT_SKIP_INITIAL		= 32,
 };
 
-unsigned int sysctl_sched_features __read_mostly =
+const_debug unsigned int sysctl_sched_features __read_mostly =
 		SCHED_FEAT_FAIR_SLEEPERS	*1 |
 		SCHED_FEAT_SLEEPER_AVG		*1 |
 		SCHED_FEAT_SLEEPER_LOAD_AVG	*1 |
@@ -1072,7 +1078,6 @@ static void task_new_fair(struct rq *rq,
 		p->se.wait_runtime = -(sysctl_sched_granularity / 2);
 
 	__enqueue_entity(cfs_rq, se);
-	inc_nr_running(p, rq, now);
 }
 
 #ifdef CONFIG_FAIR_GROUP_SCHED
Index: linux/kernel/sched_rt.c
===================================================================
--- linux.orig/kernel/sched_rt.c
+++ linux/kernel/sched_rt.c
@@ -229,15 +229,6 @@ static void task_tick_rt(struct rq *rq, 
 	requeue_task_rt(rq, p);
 }
 
-/*
- * No parent/child timeslice management necessary for RT tasks,
- * just activate them:
- */
-static void task_new_rt(struct rq *rq, struct task_struct *p)
-{
-	activate_task(rq, p, 1);
-}
-
 static struct sched_class rt_sched_class __read_mostly = {
 	.enqueue_task		= enqueue_task_rt,
 	.dequeue_task		= dequeue_task_rt,
@@ -251,5 +242,4 @@ static struct sched_class rt_sched_class
 	.load_balance		= load_balance_rt,
 
 	.task_tick		= task_tick_rt,
-	.task_new		= task_new_rt,
 };

Re: lmbench ctxsw regression with CFS

[Nick Piggin]

On Thu, Aug 02, 2007 at 05:44:47PM +0200, Ingo Molnar wrote:
> 
> * Nick Piggin <npiggin@suse.de> wrote:
> 
> > > > > One thing to check out is whether the lmbench numbers are 
> > > > > "correct". Especially on SMP systems, the lmbench numbers are 
> > > > > actually *best* when the two processes run on the same CPU, even 
> > > > > though that's not really at all the best scheduling - it's just 
> > > > > that it artificially improves lmbench numbers because of the 
> > > > > close cache affinity for the pipe data structures.
> > > > 
> > > > Yes, I bound them to a single core.
> > > 
> > > could you send me the .config you used?
> > 
> > Sure, attached...
> > 
> > You don't see a regression? If not, then can you send me the .config 
> > you used? [...]
> 
> i used your config to get a few numbers and to see what happens. Here's 
> the numbers of 10 consecutive "lat_ctx -s 0 2" runs:
> 
>                         [ time in micro-seconds, smaller is better ]
> 
>         v2.6.22         v2.6.23-git          v2.6.23-git+const-param
>         -------         -----------          -----------------------
>          1.30              1.60                       1.19
>          1.30              1.36                       1.18
>          1.14              1.50                       1.01
>          1.26              1.27                       1.23
>          1.22              1.40                       1.04
>          1.13              1.34                       1.09
>          1.27              1.39                       1.05
>          1.20              1.30                       1.16
>          1.20              1.17                       1.16
>          1.25              1.33                       1.01
>        -------------------------------------------------------------
>   avg:   1.22              1.36 (+11.3%)              1.11 (-10.3%)
>   min:   1.13              1.17 ( +3.5%)              1.01 (-11.8%)
>   max:   1.27              1.60 (+26.0%)              1.23 ( -3.2%)
> 
> one reason for the extra overhead is the current tunability of CFS, but 
> that is not fundamental, it's caused by the many knobs that CFS has at 
> the moment. The const-tuning patch (attached below, results in the 
> rightmost column) changes those knobs to constants, allowing the 
> compiler to optimize the math better and reduce code size. (the code 
> movement in the patch makes up for most of its size, the change that it 
> does is simple otherwise.)

[...]

Oh good. Thanks for getting to the bottom of it. We have normally
disliked too much runtime tunables in the scheduler, so I assume
these are mostly going away or under a CONFIG option for 2.6.23?
Or...?

What CPU did you get these numbers on? Do the indirect calls hurt
much on those without an indirect predictor? (I'll try running some
tests).

I must say that I don't really like the indirect calls a great deal,
and they could be eliminated just with a couple of branches and
direct calls.

Re: lmbench ctxsw regression with CFS

[Ingo Molnar]

* Nick Piggin <npiggin@suse.de> wrote:

> Oh good. Thanks for getting to the bottom of it. We have normally 
> disliked too much runtime tunables in the scheduler, so I assume these 
> are mostly going away or under a CONFIG option for 2.6.23? Or...?

yeah, they are all already under CONFIG_SCHED_DEBUG. (it's just that the 
add-on optimization is not upstream yet - the tunings are still being 
tested) Btw., with SCHED_DEBUG we now also have your domain-tree sysctl 
patch upstream, which has been in -mm for a near eternity.

> What CPU did you get these numbers on? Do the indirect calls hurt much 
> on those without an indirect predictor? (I'll try running some tests).

it was on an older Athlon64 X2. I never saw indirect calls really 
hurting on modern x86 CPUs - dont both CPU makers optimize them pretty 
efficiently? (as long as the target function is always the same - which 
it is here.)

> I must say that I don't really like the indirect calls a great deal, 
> and they could be eliminated just with a couple of branches and direct 
> calls.

yeah - i'll try that too. We can make the indirect call the uncommon 
case and a NULL pointer be the common case, combined with a 'default', 
direct function call. But i doubt it makes a big (or even measurable) 
difference.

	Ingo

Re: lmbench ctxsw regression with CFS

[Nick Piggin]

On Sat, Aug 04, 2007 at 08:50:37AM +0200, Ingo Molnar wrote:
> 
> * Nick Piggin <npiggin@suse.de> wrote:
> 
> > Oh good. Thanks for getting to the bottom of it. We have normally 
> > disliked too much runtime tunables in the scheduler, so I assume these 
> > are mostly going away or under a CONFIG option for 2.6.23? Or...?
> 
> yeah, they are all already under CONFIG_SCHED_DEBUG. (it's just that the 
> add-on optimization is not upstream yet - the tunings are still being 

Ah, OK. So long as that goes upstream I'm happy... and it is good
to see that with that patch, the base context switching performance
_has_ actually gone up like I had hoped. Nice.


> tested) Btw., with SCHED_DEBUG we now also have your domain-tree sysctl 
> patch upstream, which has been in -mm for a near eternity.
> 
> > What CPU did you get these numbers on? Do the indirect calls hurt much 
> > on those without an indirect predictor? (I'll try running some tests).
> 
> it was on an older Athlon64 X2. I never saw indirect calls really 
> hurting on modern x86 CPUs - dont both CPU makers optimize them pretty 
> efficiently? (as long as the target function is always the same - which 
> it is here.)

I think a lot of CPUs do. I think ia64 does not. It predicts
based on the contents of a branch target register which has to
be loaded I presume before instructoin fetch reaches the branch.
I don't know if this would hurt or not.


> > I must say that I don't really like the indirect calls a great deal, 
> > and they could be eliminated just with a couple of branches and direct 
> > calls.
> 
> yeah - i'll try that too. We can make the indirect call the uncommon 
> case and a NULL pointer be the common case, combined with a 'default', 
> direct function call. But i doubt it makes a big (or even measurable) 
> difference.

You might be right there.

Re: lmbench ctxsw regression with CFS

[Jens Axboe]

On Mon, Aug 06 2007, Nick Piggin wrote:
> > > What CPU did you get these numbers on? Do the indirect calls hurt much 
> > > on those without an indirect predictor? (I'll try running some tests).
> > 
> > it was on an older Athlon64 X2. I never saw indirect calls really 
> > hurting on modern x86 CPUs - dont both CPU makers optimize them pretty 
> > efficiently? (as long as the target function is always the same - which 
> > it is here.)
> 
> I think a lot of CPUs do. I think ia64 does not. It predicts
> based on the contents of a branch target register which has to
> be loaded I presume before instructoin fetch reaches the branch.
> I don't know if this would hurt or not.

Testing on ia64 showed that the indirect calls in the io scheduler hurt
quite a bit, so I'd be surprised if the impact here wasn't an issue
there.

-- 
Jens Axboe

Re: lmbench ctxsw regression with CFS

[Andrew Morton]

On Mon, 13 Aug 2007 14:30:31 +0200 Jens Axboe <jens.axboe@oracle.com> wrote:

> On Mon, Aug 06 2007, Nick Piggin wrote:
> > > > What CPU did you get these numbers on? Do the indirect calls hurt much 
> > > > on those without an indirect predictor? (I'll try running some tests).
> > > 
> > > it was on an older Athlon64 X2. I never saw indirect calls really 
> > > hurting on modern x86 CPUs - dont both CPU makers optimize them pretty 
> > > efficiently? (as long as the target function is always the same - which 
> > > it is here.)
> > 
> > I think a lot of CPUs do. I think ia64 does not. It predicts
> > based on the contents of a branch target register which has to
> > be loaded I presume before instructoin fetch reaches the branch.
> > I don't know if this would hurt or not.
> 
> Testing on ia64 showed that the indirect calls in the io scheduler hurt
> quite a bit, so I'd be surprised if the impact here wasn't an issue
> there.

With what workload?  lmbench ctxsw?  Who cares?

Look, if you're doing 100,000 context switches per second per then *that*
is your problem.  You suck, and making context switches a bit faster
doesn't stop you from sucking.  And ten microseconds is a very long time
indeed.

Put it this way: if a 50% slowdown in context switch times yields a 5%
improvement in, say, balancing decisions then it's probably a net win.

Guys, repeat after me: "context switch is not a fast path".  Take that
benchmark and set fire to it.

Re: lmbench ctxsw regression with CFS

[Nick Piggin]

On Mon, Aug 13, 2007 at 08:00:38PM -0700, Andrew Morton wrote:
> On Mon, 13 Aug 2007 14:30:31 +0200 Jens Axboe <jens.axboe@oracle.com> wrote:
> 
> > On Mon, Aug 06 2007, Nick Piggin wrote:
> > > > > What CPU did you get these numbers on? Do the indirect calls hurt much 
> > > > > on those without an indirect predictor? (I'll try running some tests).
> > > > 
> > > > it was on an older Athlon64 X2. I never saw indirect calls really 
> > > > hurting on modern x86 CPUs - dont both CPU makers optimize them pretty 
> > > > efficiently? (as long as the target function is always the same - which 
> > > > it is here.)
> > > 
> > > I think a lot of CPUs do. I think ia64 does not. It predicts
> > > based on the contents of a branch target register which has to
> > > be loaded I presume before instructoin fetch reaches the branch.
> > > I don't know if this would hurt or not.
> > 
> > Testing on ia64 showed that the indirect calls in the io scheduler hurt
> > quite a bit, so I'd be surprised if the impact here wasn't an issue
> > there.
> 
> With what workload?  lmbench ctxsw?  Who cares?
> 
> Look, if you're doing 100,000 context switches per second per then *that*
> is your problem.  You suck, and making context switches a bit faster
> doesn't stop you from sucking.  And ten microseconds is a very long time
> indeed.
> 
> Put it this way: if a 50% slowdown in context switch times yields a 5%
> improvement in, say, balancing decisions then it's probably a net win.
> 
> Guys, repeat after me: "context switch is not a fast path".  Take that
> benchmark and set fire to it.

It definitely can be. For workloads that are inherently asynchronous, high
speed networking or disk IO (ie. with event generation significantly outside
the control of the kernel or app), then it can be. Sure, you may just be
switching between the main working thread and idle thread, but in that case a
slowdown in the scheduler will be _more_ pronounced because you don't have to
do as much work to actually switch contexts.

If there was a performance tradeoff involved, then we could think about it,
and you might be right. But this is just a case of "write code to do direct
calls or do indirect calls".

Ken Chen's last ia64 database benchmark I could find says schedule takes
6.5% of the clock cycles, the second highest consumer. Considering the
lengths he was going to shave cycles off other paths, I'd call schedule()
a fastpath. Would be really interesting to rerun that benchmark with CFS.
Is anyone at Intel still doing those tests?

Re: lmbench ctxsw regression with CFS

[Siddha, Suresh B]

On Tue, Aug 14, 2007 at 05:23:00AM +0200, Nick Piggin wrote:
> On Mon, Aug 13, 2007 at 08:00:38PM -0700, Andrew Morton wrote:
> > Put it this way: if a 50% slowdown in context switch times yields a 5%
> > improvement in, say, balancing decisions then it's probably a net win.
> > 
> > Guys, repeat after me: "context switch is not a fast path".  Take that
> > benchmark and set fire to it.
> 
> It definitely can be. For workloads that are inherently asynchronous, high
> speed networking or disk IO (ie. with event generation significantly outside
> the control of the kernel or app), then it can be. Sure, you may just be
> switching between the main working thread and idle thread, but in that case a
> slowdown in the scheduler will be _more_ pronounced because you don't have to
> do as much work to actually switch contexts.
> 
> If there was a performance tradeoff involved, then we could think about it,
> and you might be right. But this is just a case of "write code to do direct
> calls or do indirect calls".
> 
> Ken Chen's last ia64 database benchmark I could find says schedule takes
> 6.5% of the clock cycles, the second highest consumer. Considering the
> lengths he was going to shave cycles off other paths, I'd call schedule()
> a fastpath. Would be really interesting to rerun that benchmark with CFS.
> Is anyone at Intel still doing those tests?

Yes. schedule() still is in the top 2-3 consumers of kernel time for that
workload. We did some tests when CFS was in initial days (I think V2 or so)
and it didn't show any regression.

We have plans to run that workload with 2.6.23-rc kernels, but other things
were taking priority so far...

thanks,
suresh

Re: lmbench ctxsw regression with CFS

[David Miller]

From: Andrew Morton <akpm@linux-foundation.org>
Date: Mon, 13 Aug 2007 20:00:38 -0700

> Guys, repeat after me: "context switch is not a fast path".  Take
> that benchmark and set fire to it.

Nothing in this world is so absolute :-)

Regardless of the value of lat_ctx, we should thank it for showing
that something is more expensive now.  And it definitely warrants
figuring out what paths are big cycle eaters now and why.

Not "on IA64 indirect calls are expensive, so that must be it", but
rather doing cycle analysis of the relevant scheduling functions to
figure out what might be wrong.

I'm willing to bet it's something completely trivial and easy
to amend, rather than a fundamental issue.  But somebody has
to _look_ instead of supposing this and that.