* [uml-devel] g_timeout_add @ 2008-02-13 19:57 clowncoder 2008-02-14 0:38 ` Jeff Dike 0 siblings, 1 reply; 15+ messages in thread From: clowncoder @ 2008-02-13 19:57 UTC (permalink / raw) To: user-mode-linux-devel Hello, It seems that g_timeout_add glib timeouts are not accurate when there is no gtk activity on an uml target. This may be a glib problem since I cannot check that it does not occur on my host. When gtk events occur through mouse moves, then the timeout is good (a 5 sec timeout) if no graphical activity exists, the timeout takes an average of 12 sec, even if there is console activity on the uml machine. Sorry that my host has no gtk to double-check on a physical machine. Vincent Perrier ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [uml-devel] g_timeout_add 2008-02-13 19:57 [uml-devel] g_timeout_add clowncoder @ 2008-02-14 0:38 ` Jeff Dike 2008-02-14 22:16 ` clowncoder 2008-02-21 22:02 ` [uml-devel] Timeout in the select clowncoder 0 siblings, 2 replies; 15+ messages in thread From: Jeff Dike @ 2008-02-14 0:38 UTC (permalink / raw) To: clowncoder; +Cc: user-mode-linux-devel On Wed, Feb 13, 2008 at 08:57:20PM +0100, clowncoder wrote: > It seems that g_timeout_add glib timeouts are not accurate > when there is no gtk activity on an uml target. > > This may be a glib problem since I cannot check > that it does not occur on my host. > > When gtk events occur through mouse moves, then > the timeout is good (a 5 sec timeout) if no graphical > activity exists, the timeout takes an average of 12 sec, > even if there is console activity on the uml machine. You're going to need to tell me what's happening at the system call level - i.e. strace it and see what is doing something it shouldn't. Jeff -- Work email - jdike at linux dot intel dot com ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [uml-devel] g_timeout_add 2008-02-14 0:38 ` Jeff Dike @ 2008-02-14 22:16 ` clowncoder 2008-02-15 16:02 ` Jeff Dike 2008-02-21 22:02 ` [uml-devel] Timeout in the select clowncoder 1 sibling, 1 reply; 15+ messages in thread From: clowncoder @ 2008-02-14 22:16 UTC (permalink / raw) To: Jeff Dike; +Cc: user-mode-linux-devel With strace, when I do nothing on the gtk screen, we get what is under, it seems that the poll has a 5000 milli-sec timeout, but takes 10 sec to wake. When I move the mouse on the gtk screen, there are too many events on the screen to see anything but I can send it if you need it. gettimeofday({1203026980, 431960}, NULL) = 0 poll([{fd=3, events=POLLIN}], 1, 5000) = 0 gettimeofday({1203026990, 459054}, NULL) = 0 gettimeofday({1203026990, 459250}, NULL) = 0 write(1, "1203026990\n", 111203026990 ) = 11 read(3, 0x809e004, 4096) = -1 EAGAIN (Resource temporarily unavailable) gettimeofday({1203026990, 459871}, NULL) = 0 poll([{fd=3, events=POLLIN}], 1, 5000) = 0 gettimeofday({1203027000, 470939}, NULL) = 0 gettimeofday({1203027000, 471136}, NULL) = 0 write(1, "1203027000\n", 111203027000 ) = 11 Jeff Dike wrote: > On Wed, Feb 13, 2008 at 08:57:20PM +0100, clowncoder wrote: > >> It seems that g_timeout_add glib timeouts are not accurate >> when there is no gtk activity on an uml target. >> >> This may be a glib problem since I cannot check >> that it does not occur on my host. >> >> When gtk events occur through mouse moves, then >> the timeout is good (a 5 sec timeout) if no graphical >> activity exists, the timeout takes an average of 12 sec, >> even if there is console activity on the uml machine. >> > > You're going to need to tell me what's happening at the system call > level - i.e. strace it and see what is doing something it shouldn't. > > Jeff > > ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [uml-devel] g_timeout_add 2008-02-14 22:16 ` clowncoder @ 2008-02-15 16:02 ` Jeff Dike 2008-02-15 17:39 ` clowncoder 0 siblings, 1 reply; 15+ messages in thread From: Jeff Dike @ 2008-02-15 16:02 UTC (permalink / raw) To: clowncoder; +Cc: user-mode-linux-devel On Thu, Feb 14, 2008 at 11:16:45PM +0100, clowncoder wrote: > With strace, when I do nothing on the gtk screen, we get > what is under, it seems that the poll has a 5000 milli-sec > timeout, but takes 10 sec to wake. Can you show that with timestamps (strace -ttt)? Jeff -- Work email - jdike at linux dot intel dot com ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [uml-devel] g_timeout_add 2008-02-15 16:02 ` Jeff Dike @ 2008-02-15 17:39 ` clowncoder 2008-02-15 18:46 ` Jeff Dike 0 siblings, 1 reply; 15+ messages in thread From: clowncoder @ 2008-02-15 17:39 UTC (permalink / raw) To: Jeff Dike; +Cc: user-mode-linux-devel Here it is: By the way, do you use other very interresting tools such as strace? if so could you give me names? 1203096910.892244 poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}], 2, 4994) = 0 1203096922.904300 gettimeofday({1203096922, 904988}, NULL) = 0 1203096922.905867 gettimeofday({1203096922, 906552}, NULL) = 0 1203096922.907449 write(1, "1203096922\n", 111203096922 ) = 11 1203096922.909681 read(3, 0x809e004, 4096) = -1 EAGAIN (Resource temporarily unavailable) 1203096922.911270 gettimeofday({1203096922, 911946}, NULL) = 0 1203096922.912827 poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}], 2, 4994) = 0 1203096934.924538 gettimeofday({1203096934, 924926}, NULL) = 0 1203096934.925477 gettimeofday({1203096934, 925851}, NULL) = 0 1203096934.926400 write(1, "1203096934\n", 111203096934 ) = 11 1203096934.927673 read(3, 0x809e004, 4096) = -1 EAGAIN (Resource temporarily unavailable) 1203096934.928613 gettimeofday({1203096934, 928937}, NULL) = 0 1203096934.929524 poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}], 2, 4996) = 0 1203096946.929030 gettimeofday({1203096946, 929420}, NULL) = 0 1203096946.929968 gettimeofday({1203096946, 930339}, NULL) = 0 1203096946.930882 write(1, "1203096946\n", 111203096946 ) = 11 1203096946.932147 read(3, 0x809e004, 4096) = -1 EAGAIN (Resource temporarily unavailable) 1203096946.933062 gettimeofday({1203096946, 933422}, NULL) = 0 1203096946.933947 poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}], 2, 4996) = 0 1203096958.157856 gettimeofday({1203096958, 158538}, NULL) = 0 1203096958.159413 gettimeofday({1203096958, 160094}, NULL) = 0 1203096958.160992 write(1, "1203096958\n", 111203096958 ) = 11 Jeff Dike wrote: > On Thu, Feb 14, 2008 at 11:16:45PM +0100, clowncoder wrote: > >> With strace, when I do nothing on the gtk screen, we get >> what is under, it seems that the poll has a 5000 milli-sec >> timeout, but takes 10 sec to wake. >> > > Can you show that with timestamps (strace -ttt)? > > Jeff > > ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [uml-devel] g_timeout_add 2008-02-15 17:39 ` clowncoder @ 2008-02-15 18:46 ` Jeff Dike 2008-03-14 23:01 ` [uml-devel] [2.6.24.x] UML select()/poll() oversleeping reproducibly (was Re: g_timeout_add) Nix 0 siblings, 1 reply; 15+ messages in thread From: Jeff Dike @ 2008-02-15 18:46 UTC (permalink / raw) To: clowncoder; +Cc: user-mode-linux-devel On Fri, Feb 15, 2008 at 06:39:12PM +0100, clowncoder wrote: > By the way, do you use other very interresting tools such as strace? > if so could you give me names? strace is the major one. > 1203096946.933947 poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}], > 2, 4996) = 0 > 1203096958.157856 gettimeofday({1203096958, 158538}, NULL) = 0 The smoking gun - a poll that should have timed out in .5 sec slept for 12. Now, can you do it again, but strace UML on the host at the same time, with -ttt? Jeff -- Work email - jdike at linux dot intel dot com ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ^ permalink raw reply [flat|nested] 15+ messages in thread
* [uml-devel] [2.6.24.x] UML select()/poll() oversleeping reproducibly (was Re: g_timeout_add) 2008-02-15 18:46 ` Jeff Dike @ 2008-03-14 23:01 ` Nix 2008-03-17 16:27 ` Jeff Dike ` (2 more replies) 0 siblings, 3 replies; 15+ messages in thread From: Nix @ 2008-03-14 23:01 UTC (permalink / raw) To: Jeff Dike Cc: Thomas Gleixner, linux-kernel Mailing List, user-mode-linux-devel On 15 Feb 2008, Jeff Dike told this: > The smoking gun - a poll that should have timed out in .5 sec slept > for 12. FWIW this breaks all sorts of things, as one might expect: obviously it breaks select() as well as poll(). For me the symptoms were a failure of DHCP and spontaneous dropping off the net because lease renewal wasn't happening in time (with 2.6.24.3, not with 2.6.24.2 that I can see). The precise degree of oversleeping seems to depend on the clocksource in use on the host (all hosts here are lightly loaded, running on 2.6.24.2 throughout these tests: select() does not wait for way too long here). On a 1.4GHz Athlon IV using the tsc clocksource, I see consistent oversleeps, but not enormous ones: bash-3.2# ./select-sleep 1 Slept for 1 seconds. bash-3.2# ./select-sleep 5 Slept for 7 seconds. bash-3.2# ./select-sleep 5 Slept for 7 seconds. bash-3.2# ./select-sleep 10 Slept for 13 seconds. bash-3.2# ./select-sleep 30 Slept for 39 seconds. bash-3.2# ./select-sleep 30 Slept for 39 seconds. bash-3.2# ./select-sleep 60 Slept for 78 seconds. On a 900MHz PIII using the pit clocksource (ick, why the hell isn't it using tsc? oh, tsc unstable, how helpful) I see huge discrepancies, still consistent, and interestingly all exactly four times as long as we asked to sleep: bash-3.2# ./select-sleep 1 Slept for 4 seconds. bash-3.2# ./select-sleep 5 Slept for 20 seconds. bash-3.2# ./select-sleep 5 Slept for 20 seconds. bash-3.2# ./select-sleep 30 Slept for 120 seconds. bash-3.2# ./select-sleep 30 Slept for 120 seconds. bash-3.2# ./select-sleep 60 Slept for 240 seconds. I'll do the -ttt UML tracing you requested next. I'm testing using a little filesystem image containing a shell, glibc, and this trivial obvious five-minute hack: #define _POSIX_C_SOURCE 200112L #include <stdio.h> #include <stdlib.h> #include <sys/select.h> #include <sys/time.h> int main (int argc, char *argv[]) { long interval; struct timeval now; struct timeval timeout; struct timeval then; char *converr; fd_set foo; if (argc != 2) { fprintf (stderr, "Syntax: select-sleep INTERVAL\n"); return 1; } interval = strtol (argv[1], &converr, 10); if (*converr != '\0') { fprintf (stderr, "Cannot convert %s to an integer\n", argv[1]); return 2; } gettimeofday (&then, NULL); timeout.tv_sec = interval; timeout.tv_usec = 0; FD_ZERO(&foo); select (0, NULL, NULL, NULL, &timeout); /* Watch me not care about not EINTR, I'm interested in *overlong* sleeps */ gettimeofday (&now, NULL); fprintf (stderr, "Slept for %li seconds.\n", now.tv_sec - then.tv_sec); return 0; } The UML's .config: CONFIG_DEFCONFIG_LIST="arch/$ARCH/defconfig" CONFIG_GENERIC_HARDIRQS=y CONFIG_UML=y CONFIG_MMU=y CONFIG_NO_IOMEM=y CONFIG_LOCKDEP_SUPPORT=y CONFIG_GENERIC_CALIBRATE_DELAY=y CONFIG_GENERIC_BUG=y CONFIG_GENERIC_TIME=y CONFIG_GENERIC_CLOCKEVENTS=y CONFIG_IRQ_RELEASE_METHOD=y CONFIG_MPENTIUMIII=y CONFIG_X86_CMPXCHG=y CONFIG_X86_L1_CACHE_SHIFT=5 CONFIG_X86_XADD=y CONFIG_X86_WP_WORKS_OK=y CONFIG_X86_INVLPG=y CONFIG_X86_BSWAP=y CONFIG_X86_POPAD_OK=y CONFIG_X86_GOOD_APIC=y CONFIG_X86_INTEL_USERCOPY=y CONFIG_X86_USE_PPRO_CHECKSUM=y CONFIG_X86_TSC=y CONFIG_X86_CMOV=y CONFIG_X86_MINIMUM_CPU_FAMILY=4 CONFIG_UML_X86=y CONFIG_X86_32=y CONFIG_RWSEM_XCHGADD_ALGORITHM=y CONFIG_SEMAPHORE_SLEEPERS=y CONFIG_HOST_VMSPLIT_3G=y CONFIG_TOP_ADDR=0xC0000000 CONFIG_ARCH_HAS_SC_SIGNALS=y CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA=y CONFIG_GENERIC_HWEIGHT=y CONFIG_SELECT_MEMORY_MODEL=y CONFIG_FLATMEM_MANUAL=y CONFIG_FLATMEM=y CONFIG_FLAT_NODE_MEM_MAP=y CONFIG_SPLIT_PTLOCK_CPUS=4 CONFIG_ZONE_DMA_FLAG=0 CONFIG_VIRT_TO_BUS=y CONFIG_GENERIC_CLOCKEVENTS_BUILD=y CONFIG_LD_SCRIPT_DYN=y CONFIG_NET=y CONFIG_BINFMT_ELF=y CONFIG_MCONSOLE=y CONFIG_NEST_LEVEL=0 CONFIG_KERNEL_STACK_ORDER=2 CONFIG_EXPERIMENTAL=y CONFIG_BROKEN_ON_SMP=y CONFIG_INIT_ENV_ARG_LIMIT=128 CONFIG_LOCALVERSION="" CONFIG_SYSVIPC=y CONFIG_SYSVIPC_SYSCTL=y CONFIG_POSIX_MQUEUE=y CONFIG_BSD_PROCESS_ACCT=y CONFIG_LOG_BUF_SHIFT=14 CONFIG_FAIR_GROUP_SCHED=y CONFIG_FAIR_USER_SCHED=y CONFIG_RELAY=y CONFIG_CC_OPTIMIZE_FOR_SIZE=y CONFIG_SYSCTL=y CONFIG_UID16=y CONFIG_SYSCTL_SYSCALL=y CONFIG_KALLSYMS=y 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_EVENTFD=y CONFIG_SHMEM=y CONFIG_VM_EVENT_COUNTERS=y CONFIG_SLAB=y CONFIG_SLABINFO=y CONFIG_RT_MUTEXES=y CONFIG_BASE_SMALL=0 CONFIG_BLOCK=y CONFIG_BLK_DEV_IO_TRACE=y CONFIG_IOSCHED_NOOP=y CONFIG_IOSCHED_DEADLINE=y CONFIG_DEFAULT_DEADLINE=y CONFIG_DEFAULT_IOSCHED="deadline" CONFIG_BLK_DEV=y CONFIG_BLK_DEV_UBD=y CONFIG_BLK_DEV_COW_COMMON=y CONFIG_STDERR_CONSOLE=y CONFIG_STDIO_CONSOLE=y CONFIG_SSL=y CONFIG_NULL_CHAN=y CONFIG_PORT_CHAN=y CONFIG_PTY_CHAN=y CONFIG_TTY_CHAN=y CONFIG_XTERM_CHAN=y CONFIG_CON_ZERO_CHAN="fd:0,fd:1" CONFIG_CON_CHAN="tty" CONFIG_SSL_CHAN="pty" CONFIG_UNIX98_PTYS=y CONFIG_UML_RANDOM=y CONFIG_UEVENT_HELPER_PATH="/sbin/hotplug" CONFIG_STANDALONE=y CONFIG_PREVENT_FIRMWARE_BUILD=y CONFIG_PACKET=y CONFIG_PACKET_MMAP=y CONFIG_UNIX=y CONFIG_INET=y CONFIG_IP_MULTICAST=y CONFIG_IP_ADVANCED_ROUTER=y CONFIG_ASK_IP_FIB_HASH=y CONFIG_IP_FIB_HASH=y CONFIG_IP_MULTIPLE_TABLES=y CONFIG_SYN_COOKIES=y CONFIG_INET_DIAG=y CONFIG_INET_TCP_DIAG=y CONFIG_TCP_CONG_ADVANCED=y CONFIG_TCP_CONG_CUBIC=y CONFIG_DEFAULT_CUBIC=y CONFIG_DEFAULT_TCP_CONG="cubic" CONFIG_NETFILTER=y CONFIG_NF_CONNTRACK_ENABLED=y CONFIG_NF_CONNTRACK=y CONFIG_NF_CT_ACCT=y CONFIG_NF_CONNTRACK_MARK=y CONFIG_NF_CT_PROTO_UDPLITE=y CONFIG_NF_CONNTRACK_FTP=y CONFIG_NF_CONNTRACK_IRC=y CONFIG_NF_CONNTRACK_SIP=y CONFIG_NETFILTER_XTABLES=y CONFIG_NETFILTER_XT_TARGET_CLASSIFY=y CONFIG_NETFILTER_XT_TARGET_MARK=y CONFIG_NETFILTER_XT_TARGET_NFQUEUE=y CONFIG_NETFILTER_XT_MATCH_CONNLIMIT=y CONFIG_NETFILTER_XT_MATCH_CONNMARK=y CONFIG_NETFILTER_XT_MATCH_HELPER=y CONFIG_NETFILTER_XT_MATCH_LIMIT=y CONFIG_NETFILTER_XT_MATCH_MARK=y CONFIG_NETFILTER_XT_MATCH_MULTIPORT=y CONFIG_NETFILTER_XT_MATCH_QUOTA=y CONFIG_NETFILTER_XT_MATCH_STATE=y CONFIG_NETFILTER_XT_MATCH_HASHLIMIT=y CONFIG_NF_CONNTRACK_IPV4=y CONFIG_NF_CONNTRACK_PROC_COMPAT=y CONFIG_IP_NF_IPTABLES=y CONFIG_IP_NF_MATCH_IPRANGE=y CONFIG_IP_NF_MATCH_TOS=y CONFIG_IP_NF_MATCH_RECENT=y 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_NF_NAT=y CONFIG_NF_NAT_NEEDED=y CONFIG_IP_NF_TARGET_REDIRECT=y CONFIG_NF_NAT_FTP=y CONFIG_NF_NAT_IRC=y CONFIG_NF_NAT_SIP=y CONFIG_IP_NF_MANGLE=y CONFIG_IP_NF_TARGET_TOS=y CONFIG_IP_NF_TARGET_ECN=y CONFIG_NET_SCHED=y CONFIG_NET_SCH_CBQ=y CONFIG_NET_SCH_HTB=y CONFIG_NET_SCH_HFSC=y CONFIG_NET_SCH_PRIO=y CONFIG_NET_SCH_RED=y CONFIG_NET_SCH_SFQ=y CONFIG_NET_SCH_TEQL=y CONFIG_NET_SCH_TBF=y CONFIG_NET_SCH_GRED=y CONFIG_NET_SCH_DSMARK=y CONFIG_NET_SCH_INGRESS=y CONFIG_NET_CLS=y CONFIG_NET_CLS_BASIC=y CONFIG_NET_CLS_TCINDEX=y CONFIG_NET_CLS_ROUTE4=y CONFIG_NET_CLS_ROUTE=y CONFIG_NET_CLS_FW=y CONFIG_NET_CLS_U32=y CONFIG_CLS_U32_PERF=y CONFIG_CLS_U32_MARK=y CONFIG_NET_CLS_RSVP=y CONFIG_NET_EMATCH=y CONFIG_NET_EMATCH_STACK=32 CONFIG_NET_EMATCH_CMP=y CONFIG_NET_EMATCH_NBYTE=y CONFIG_NET_EMATCH_U32=y CONFIG_NET_EMATCH_META=y CONFIG_NET_CLS_ACT=y CONFIG_NET_ACT_POLICE=y CONFIG_NET_ACT_GACT=y CONFIG_NET_ACT_PEDIT=y CONFIG_NET_SCH_FIFO=y CONFIG_FIB_RULES=y CONFIG_UML_NET=y CONFIG_UML_NET_TUNTAP=y CONFIG_NETDEVICES=y CONFIG_DUMMY=y CONFIG_TUN=y CONFIG_EXT2_FS=y CONFIG_EXT2_FS_XATTR=y CONFIG_EXT2_FS_POSIX_ACL=y CONFIG_EXT2_FS_SECURITY=y CONFIG_FS_MBCACHE=y CONFIG_FS_POSIX_ACL=y CONFIG_INOTIFY=y CONFIG_INOTIFY_USER=y CONFIG_QUOTA=y CONFIG_PRINT_QUOTA_WARNING=y CONFIG_QUOTACTL=y CONFIG_DNOTIFY=y CONFIG_GENERIC_ACL=y CONFIG_PROC_FS=y CONFIG_PROC_SYSCTL=y CONFIG_SYSFS=y CONFIG_TMPFS=y CONFIG_TMPFS_POSIX_ACL=y CONFIG_CONFIGFS_FS=y CONFIG_NETWORK_FILESYSTEMS=y CONFIG_NFS_FS=y CONFIG_NFS_V3=y CONFIG_NFS_V3_ACL=y CONFIG_LOCKD=y CONFIG_LOCKD_V4=y CONFIG_NFS_ACL_SUPPORT=y CONFIG_NFS_COMMON=y CONFIG_SUNRPC=y CONFIG_MSDOS_PARTITION=y CONFIG_KEYS=y CONFIG_SECURITY=y CONFIG_SECURITY_CAPABILITIES=y CONFIG_SECURITY_FILE_CAPABILITIES=y CONFIG_CRYPTO=y CONFIG_CRYPTO_ALGAPI=y CONFIG_CRYPTO_MANAGER=y CONFIG_CRYPTO_SHA1=y CONFIG_BITREVERSE=y CONFIG_CRC32=y CONFIG_PLIST=y CONFIG_HAS_DMA=y CONFIG_INSTRUMENTATION=y CONFIG_ENABLE_WARN_DEPRECATED=y CONFIG_ENABLE_MUST_CHECK=y CONFIG_DEBUG_FS=y CONFIG_DEBUG_BUGVERBOSE=y ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [uml-devel] [2.6.24.x] UML select()/poll() oversleeping reproducibly (was Re: g_timeout_add) 2008-03-14 23:01 ` [uml-devel] [2.6.24.x] UML select()/poll() oversleeping reproducibly (was Re: g_timeout_add) Nix @ 2008-03-17 16:27 ` Jeff Dike 2008-03-17 17:03 ` Jeff Dike 2008-03-17 19:34 ` Jeff Dike 2 siblings, 0 replies; 15+ messages in thread From: Jeff Dike @ 2008-03-17 16:27 UTC (permalink / raw) To: Nix; +Cc: Thomas Gleixner, linux-kernel Mailing List, user-mode-linux-devel On Fri, Mar 14, 2008 at 11:01:35PM +0000, Nix wrote: > On a 1.4GHz Athlon IV using the tsc clocksource, I see consistent > oversleeps, but not enormous ones: > bash-3.2# ./select-sleep 10 > Slept for 13 seconds. I'm seeing the same thing with tickless disabled on current UML - stay tuned... Jeff -- Work email - jdike at linux dot intel dot com ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [uml-devel] [2.6.24.x] UML select()/poll() oversleeping reproducibly (was Re: g_timeout_add) 2008-03-14 23:01 ` [uml-devel] [2.6.24.x] UML select()/poll() oversleeping reproducibly (was Re: g_timeout_add) Nix 2008-03-17 16:27 ` Jeff Dike @ 2008-03-17 17:03 ` Jeff Dike 2008-03-17 19:34 ` Jeff Dike 2 siblings, 0 replies; 15+ messages in thread From: Jeff Dike @ 2008-03-17 17:03 UTC (permalink / raw) To: Nix; +Cc: Thomas Gleixner, linux-kernel Mailing List, user-mode-linux-devel On Fri, Mar 14, 2008 at 11:01:35PM +0000, Nix wrote: > bash-3.2# ./select-sleep 10 > Slept for 13 seconds. See what kind of difference the patch below makes - it reduces the 30% oversleeping down to 10% for me. That's still way too much, but it's better. The problem being fixed here is that setitimer consistently returns a remaining time greater than what was originally requested, by ~20%: 1205773032.413780 setitimer(ITIMER_VIRTUAL, {it_interval={0, 10000}, it_value={0, 10000}}, NULL) = 0 1205773032.413814 setitimer(ITIMER_VIRTUAL, {it_interval={0, 0}, it_value={0, 0}}, {it_interval={0, 10998}, it_value={0, 11998}}) = 0 This is setting a 100 HZ timer, immediately followed by a cancellation which also requests the amount left on the timer. The interval is rounded up by 10%, and the first tick by 20%. Jeff -- Work email - jdike at linux dot intel dot com Index: linux-2.6.22/arch/um/os-Linux/time.c =================================================================== --- linux-2.6.22.orig/arch/um/os-Linux/time.c 2008-02-18 11:53:51.000000000 -0500 +++ linux-2.6.22/arch/um/os-Linux/time.c 2008-03-17 12:55:41.000000000 -0400 @@ -58,12 +58,17 @@ static inline long long timeval_to_ns(co long long disable_timer(void) { struct itimerval time = ((struct itimerval) { { 0, 0 }, { 0, 0 } }); + int remain, max = UM_NSEC_PER_SEC / UM_HZ; if (setitimer(ITIMER_VIRTUAL, &time, &time) < 0) printk(UM_KERN_ERR "disable_timer - setitimer failed, " "errno = %d\n", errno); - return timeval_to_ns(&time.it_value); + remain = timeval_to_ns(&time.it_value); + if (remain > max) + remain = max; + + return remain; } long long os_nsecs(void) ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [uml-devel] [2.6.24.x] UML select()/poll() oversleeping reproducibly (was Re: g_timeout_add) 2008-03-14 23:01 ` [uml-devel] [2.6.24.x] UML select()/poll() oversleeping reproducibly (was Re: g_timeout_add) Nix 2008-03-17 16:27 ` Jeff Dike 2008-03-17 17:03 ` Jeff Dike @ 2008-03-17 19:34 ` Jeff Dike 2008-03-17 21:08 ` [uml-devel] [2.6.24.x] UML select()/poll() oversleeping reproducibly Nix 2 siblings, 1 reply; 15+ messages in thread From: Jeff Dike @ 2008-03-17 19:34 UTC (permalink / raw) To: Nix; +Cc: Thomas Gleixner, linux-kernel Mailing List, user-mode-linux-devel Below is the same patch with another kluge, which cuts down the requested sleep by 10% in hopes of getting the actual sleep closer to what's wanted. This is unusable in anything resembling mainline, but I'd like to see how your various systems react to it. I'm getting very close to the sleeps I asked for (with slight undersleeping, which is a bug). Jeff -- Work email - jdike at linux dot intel dot com Index: linux-2.6.22/arch/um/os-Linux/time.c =================================================================== --- linux-2.6.22.orig/arch/um/os-Linux/time.c 2008-02-18 11:53:51.000000000 -0500 +++ linux-2.6.22/arch/um/os-Linux/time.c 2008-03-17 15:11:51.000000000 -0400 @@ -58,12 +58,17 @@ static inline long long timeval_to_ns(co long long disable_timer(void) { struct itimerval time = ((struct itimerval) { { 0, 0 }, { 0, 0 } }); + int remain, max = UM_NSEC_PER_SEC / UM_HZ; if (setitimer(ITIMER_VIRTUAL, &time, &time) < 0) printk(UM_KERN_ERR "disable_timer - setitimer failed, " "errno = %d\n", errno); - return timeval_to_ns(&time.it_value); + remain = timeval_to_ns(&time.it_value); + if (remain > max) + remain = max; + + return remain; } long long os_nsecs(void) @@ -126,6 +131,8 @@ void idle_sleep(unsigned long long nsecs */ if (nsecs == 0) nsecs = UM_NSEC_PER_SEC / UM_HZ; + + nsecs = nsecs * 9 / 10; ts = ((struct timespec) { .tv_sec = nsecs / UM_NSEC_PER_SEC, .tv_nsec = nsecs % UM_NSEC_PER_SEC }); ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [uml-devel] [2.6.24.x] UML select()/poll() oversleeping reproducibly 2008-03-17 19:34 ` Jeff Dike @ 2008-03-17 21:08 ` Nix 2008-03-18 17:00 ` Jeff Dike 0 siblings, 1 reply; 15+ messages in thread From: Nix @ 2008-03-17 21:08 UTC (permalink / raw) To: Jeff Dike Cc: Thomas Gleixner, linux-kernel Mailing List, user-mode-linux-devel On 17 Mar 2008, Jeff Dike verbalised: > Below is the same patch with another kluge, which cuts down the > requested sleep by 10% in hopes of getting the actual sleep closer to > what's wanted. Eeuuuuw. :) > This is unusable in anything resembling mainline, but I'd like to see > how your various systems react to it. I'm getting very close to the > sleeps I asked for (with slight undersleeping, which is a bug). OK. Tests on host with clocksource pit: bash-3.2# bin/select-sleep 5 Slept for 5 seconds. bash-3.2# bin/select-sleep 10 Slept for 11 seconds. bash-3.2# bin/select-sleep 30 Slept for 31 seconds. bash-3.2# bin/select-sleep 60 Slept for 61 seconds. ... so much better than the 4x error without this patch. Tests on host with clocksource tsc: bash-3.2# bin/select-sleep 5 Slept for 5 seconds. bash-3.2# bin/select-sleep 10 Slept for 10 seconds. bash-3.2# bin/select-sleep 30 Slept for 30 seconds. bash-3.2# bin/select-sleep 60 Slept for 61 seconds. Distinctly better than without this patch. (Am I the only person who finds it strange that (some) clocksource hackers are arguing about accuracy problems in the ppm range while we're glad to get an error of `only' single seconds per minute out of it? Maybe next year we can invent the `pendulum' clocksource :) ) -- `The rest is a tale of post and counter-post.' --- Ian Rawlings describes USENET ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [uml-devel] [2.6.24.x] UML select()/poll() oversleeping reproducibly 2008-03-17 21:08 ` [uml-devel] [2.6.24.x] UML select()/poll() oversleeping reproducibly Nix @ 2008-03-18 17:00 ` Jeff Dike 2008-03-18 19:39 ` Nix 2008-03-19 22:14 ` Nix 0 siblings, 2 replies; 15+ messages in thread From: Jeff Dike @ 2008-03-18 17:00 UTC (permalink / raw) To: Nix; +Cc: Thomas Gleixner, linux-kernel Mailing List, user-mode-linux-devel Below is another patch. I was hurt and disappointed by your > Eeuuuuw. :) so I got rid of the 9/10 thing. This version keeps track of the time between ticks (as reported by the host's gettimeofday) and adjusts its sleeping and reporting ticks accordingly. It's still undersleeping a little - your little test once reported 19 seconds for a 20 second sleep. Otherwise, it's reporting sleep times that are right on the money. Jeff -- Work email - jdike at linux dot intel dot com Index: linux-2.6.22/arch/um/os-Linux/time.c =================================================================== --- linux-2.6.22.orig/arch/um/os-Linux/time.c 2008-03-18 12:32:19.000000000 -0400 +++ linux-2.6.22/arch/um/os-Linux/time.c 2008-03-18 12:45:50.000000000 -0400 @@ -11,6 +11,7 @@ #include "kern_constants.h" #include "os.h" #include "user.h" +#include "kern_util.h" int set_interval(void) { @@ -58,12 +59,17 @@ static inline long long timeval_to_ns(co long long disable_timer(void) { struct itimerval time = ((struct itimerval) { { 0, 0 }, { 0, 0 } }); + int remain, max = UM_NSEC_PER_SEC / UM_HZ; if (setitimer(ITIMER_VIRTUAL, &time, &time) < 0) printk(UM_KERN_ERR "disable_timer - setitimer failed, " "errno = %d\n", errno); - return timeval_to_ns(&time.it_value); + remain = timeval_to_ns(&time.it_value); + if (remain > max) + remain = max; + + return remain; } long long os_nsecs(void) @@ -79,7 +85,47 @@ static int after_sleep_interval(struct t { return 0; } + + +static void deliver_alarm(void) +{ + alarm_handler(SIGVTALRM, NULL); +} + +static unsigned long long sleep_time(unsigned long long nsecs) +{ + return nsecs; +} + #else +unsigned long long last_tick; +unsigned long long skew; + +extern void alarm_handler(int sig, struct sigcontext *sc); + +static void deliver_alarm(void) +{ + unsigned long long this_tick = os_nsecs(); + int one_tick = UM_NSEC_PER_SEC / UM_HZ; + + if (last_tick == 0) + last_tick = this_tick - one_tick; + + skew += this_tick - last_tick; + + while (skew >= one_tick) { + alarm_handler(SIGVTALRM, NULL); + skew -= one_tick; + } + + last_tick = this_tick; +} + +static unsigned long long sleep_time(unsigned long long nsecs) +{ + return nsecs > skew ? nsecs - skew : 0; +} + static inline long long timespec_to_us(const struct timespec *ts) { return ((long long) ts->tv_sec * UM_USEC_PER_SEC) + @@ -102,6 +148,8 @@ static int after_sleep_interval(struct t */ if (start_usecs > usec) start_usecs = usec; + + start_usecs -= skew / UM_NSEC_PER_USEC; tv = ((struct timeval) { .tv_sec = start_usecs / UM_USEC_PER_SEC, .tv_usec = start_usecs % UM_USEC_PER_SEC }); interval = ((struct itimerval) { { 0, usec }, tv }); @@ -113,8 +161,6 @@ static int after_sleep_interval(struct t } #endif -extern void alarm_handler(int sig, struct sigcontext *sc); - void idle_sleep(unsigned long long nsecs) { struct timespec ts; @@ -126,10 +172,12 @@ void idle_sleep(unsigned long long nsecs */ if (nsecs == 0) nsecs = UM_NSEC_PER_SEC / UM_HZ; + + nsecs = sleep_time(nsecs); ts = ((struct timespec) { .tv_sec = nsecs / UM_NSEC_PER_SEC, .tv_nsec = nsecs % UM_NSEC_PER_SEC }); if (nanosleep(&ts, &ts) == 0) - alarm_handler(SIGVTALRM, NULL); + deliver_alarm(); after_sleep_interval(&ts); } ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [uml-devel] [2.6.24.x] UML select()/poll() oversleeping reproducibly 2008-03-18 17:00 ` Jeff Dike @ 2008-03-18 19:39 ` Nix 2008-03-19 22:14 ` Nix 1 sibling, 0 replies; 15+ messages in thread From: Nix @ 2008-03-18 19:39 UTC (permalink / raw) To: Jeff Dike Cc: Thomas Gleixner, linux-kernel Mailing List, user-mode-linux-devel On 18 Mar 2008, Jeff Dike outgrape: > Below is another patch. > > I was hurt and disappointed by your >> Eeuuuuw. :) > so I got rid of the 9/10 thing. Yay! That's much less dependent on the exact nature of whatever the underlying bug is :) a random 9/10, well, it just makes my skin itch even if it does work (unless there turned out to be a fundamental reason why 9/10 was the right value, that is). > This version keeps track of the time between ticks (as reported by the > host's gettimeofday) and adjusts its sleeping and reporting ticks > accordingly. > > It's still undersleeping a little - your little test once reported 19 > seconds for a 20 second sleep. Otherwise, it's reporting sleep times > that are right on the money. I think we can live with that. Expecting perfect accuracy, even in a sleep, is hopeless unless we're niced to realtime priority in any case, and this looks like it should automatically adapt to varying load on the host as well, which is really quite neat. I'll give it an acid test (does ISC dhclient work now?) in a few hours, when I can afford to drop offline. -- `The rest is a tale of post and counter-post.' --- Ian Rawlings describes USENET ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [uml-devel] [2.6.24.x] UML select()/poll() oversleeping reproducibly 2008-03-18 17:00 ` Jeff Dike 2008-03-18 19:39 ` Nix @ 2008-03-19 22:14 ` Nix 1 sibling, 0 replies; 15+ messages in thread From: Nix @ 2008-03-19 22:14 UTC (permalink / raw) To: Jeff Dike Cc: Thomas Gleixner, linux-kernel Mailing List, user-mode-linux-devel On 18 Mar 2008, Jeff Dike told this: > This version keeps track of the time between ticks (as reported by the > host's gettimeofday) and adjusts its sleeping and reporting ticks > accordingly. I can confirm that, as expected, this patch works well enough that timing problems don't break dhclient anymore (which requires a 2x oversleep, which you're a long way from now). At last I can upgrade my firewall :) -- `The rest is a tale of post and counter-post.' --- Ian Rawlings describes USENET ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ^ permalink raw reply [flat|nested] 15+ messages in thread
* [uml-devel] Timeout in the select 2008-02-14 0:38 ` Jeff Dike 2008-02-14 22:16 ` clowncoder @ 2008-02-21 22:02 ` clowncoder 1 sibling, 0 replies; 15+ messages in thread From: clowncoder @ 2008-02-21 22:02 UTC (permalink / raw) To: Jeff Dike, user-mode-linux-devel Hello, At http://clownix.net, my new machine has the select timeout problem, if you download it, the file /usr/src/clownix_liv_feb_2008/jeff_tst.c in the virtual machine has a piece of software not behaving as it should, the 1 second timeout of the select is doubled. Could you tell me if this is specific to my machine or if others have the same problem. Regards Vincent Perrier ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ^ permalink raw reply [flat|nested] 15+ messages in thread
end of thread, other threads:[~2008-03-19 22:14 UTC | newest] Thread overview: 15+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2008-02-13 19:57 [uml-devel] g_timeout_add clowncoder 2008-02-14 0:38 ` Jeff Dike 2008-02-14 22:16 ` clowncoder 2008-02-15 16:02 ` Jeff Dike 2008-02-15 17:39 ` clowncoder 2008-02-15 18:46 ` Jeff Dike 2008-03-14 23:01 ` [uml-devel] [2.6.24.x] UML select()/poll() oversleeping reproducibly (was Re: g_timeout_add) Nix 2008-03-17 16:27 ` Jeff Dike 2008-03-17 17:03 ` Jeff Dike 2008-03-17 19:34 ` Jeff Dike 2008-03-17 21:08 ` [uml-devel] [2.6.24.x] UML select()/poll() oversleeping reproducibly Nix 2008-03-18 17:00 ` Jeff Dike 2008-03-18 19:39 ` Nix 2008-03-19 22:14 ` Nix 2008-02-21 22:02 ` [uml-devel] Timeout in the select clowncoder
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