* [PATCH 0/2] halt polling changes
@ 2016-05-13 10:16 Christian Borntraeger
2016-05-13 10:16 ` [PATCH 1/2] KVM: halt_polling: provide a way to qualify wakeups during poll Christian Borntraeger
` (2 more replies)
0 siblings, 3 replies; 8+ messages in thread
From: Christian Borntraeger @ 2016-05-13 10:16 UTC (permalink / raw)
To: Paolo Bonzini, Radim Krčmář
Cc: KVM, Cornelia Huck, linux-s390, Christian Borntraeger
Paolo, Radim,
here is the updated version of halt polling patches that improves s390.
Lots of uperf/iperf measurements showed several improvements without
things going over board. So I would like to go with this approach.
Patch 1 was several days in linux-next (I just added Radims ACk
from an earlier version), so it does not seem to break mips,arm,power and
x86.
Still ok for 4.7 or shall I defer this for 4.8?
Christian Borntraeger (2):
KVM: halt_polling: provide a way to qualify wakeups during poll
KVM: s390: set halt polling to 80 microseconds
arch/arm/include/asm/kvm_host.h | 2 ++
arch/arm64/include/asm/kvm_host.h | 2 ++
arch/mips/include/asm/kvm_host.h | 2 ++
arch/mips/kvm/mips.c | 1 +
arch/powerpc/include/asm/kvm_host.h | 2 ++
arch/powerpc/kvm/book3s.c | 1 +
arch/powerpc/kvm/booke.c | 1 +
arch/s390/include/asm/kvm_host.h | 5 ++++-
arch/s390/kvm/Kconfig | 1 +
arch/s390/kvm/interrupt.c | 5 +++++
arch/s390/kvm/kvm-s390.c | 6 ++++++
arch/x86/include/asm/kvm_host.h | 2 ++
arch/x86/kvm/x86.c | 1 +
include/linux/kvm_host.h | 15 +++++++++++++++
include/trace/events/kvm.h | 11 +++++++----
virt/kvm/Kconfig | 3 +++
virt/kvm/kvm_main.c | 8 ++++++--
17 files changed, 61 insertions(+), 7 deletions(-)
--
2.5.5
^ permalink raw reply [flat|nested] 8+ messages in thread* [PATCH 1/2] KVM: halt_polling: provide a way to qualify wakeups during poll 2016-05-13 10:16 [PATCH 0/2] halt polling changes Christian Borntraeger @ 2016-05-13 10:16 ` Christian Borntraeger 2016-05-13 12:02 ` Paolo Bonzini 2016-05-13 16:47 ` David Matlack 2016-05-13 10:16 ` [PATCH 2/2] KVM: s390: set halt polling to 80 microseconds Christian Borntraeger 2016-05-13 12:03 ` [PATCH 0/2] halt polling changes Paolo Bonzini 2 siblings, 2 replies; 8+ messages in thread From: Christian Borntraeger @ 2016-05-13 10:16 UTC (permalink / raw) To: Paolo Bonzini, Radim Krčmář Cc: KVM, Cornelia Huck, linux-s390, Christian Borntraeger Some wakeups should not be considered a sucessful poll. For example on s390 I/O interrupts are usually floating, which means that _ALL_ CPUs would be considered runnable - letting all vCPUs poll all the time for transactional like workload, even if one vCPU would be enough. This can result in huge CPU usage for large guests. This patch lets architectures provide a way to qualify wakeups if they should be considered a good/bad wakeups in regard to polls. For s390 the implementation will fence of halt polling for anything but known good, single vCPU events. The s390 implementation for floating interrupts does a wakeup for one vCPU, but the interrupt will be delivered by whatever CPU checks first for a pending interrupt. We prefer the woken up CPU by marking the poll of this CPU as "good" poll. This code will also mark several other wakeup reasons like IPI or expired timers as "good". This will of course also mark some events as not sucessful. As KVM on z runs always as a 2nd level hypervisor, we prefer to not poll, unless we are really sure, though. This patch successfully limits the CPU usage for cases like uperf 1byte transactional ping pong workload or wakeup heavy workload like OLTP while still providing a proper speedup. This also introduced a new vcpu stat "halt_poll_no_tuning" that marks wakeups that are considered not good for polling. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Radim Krčmář <rkrcmar@redhat.com> (for an earlier version) Cc: David Matlack <dmatlack@google.com> Cc: Wanpeng Li <kernellwp@gmail.com> --- arch/arm/include/asm/kvm_host.h | 2 ++ arch/arm64/include/asm/kvm_host.h | 2 ++ arch/mips/include/asm/kvm_host.h | 2 ++ arch/mips/kvm/mips.c | 1 + arch/powerpc/include/asm/kvm_host.h | 2 ++ arch/powerpc/kvm/book3s.c | 1 + arch/powerpc/kvm/booke.c | 1 + arch/s390/include/asm/kvm_host.h | 3 +++ arch/s390/kvm/Kconfig | 1 + arch/s390/kvm/interrupt.c | 5 +++++ arch/s390/kvm/kvm-s390.c | 6 ++++++ arch/x86/include/asm/kvm_host.h | 2 ++ arch/x86/kvm/x86.c | 1 + include/linux/kvm_host.h | 15 +++++++++++++++ include/trace/events/kvm.h | 11 +++++++---- virt/kvm/Kconfig | 3 +++ virt/kvm/kvm_main.c | 8 ++++++-- 17 files changed, 60 insertions(+), 6 deletions(-) diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index 3850701..4cd8732 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -187,6 +187,7 @@ struct kvm_vm_stat { struct kvm_vcpu_stat { u32 halt_successful_poll; u32 halt_attempted_poll; + u32 halt_poll_invalid; u32 halt_wakeup; u32 hvc_exit_stat; u64 wfe_exit_stat; @@ -282,6 +283,7 @@ static inline void kvm_arch_hardware_unsetup(void) {} static inline void kvm_arch_sync_events(struct kvm *kvm) {} static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} +static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {} static inline void kvm_arm_init_debug(void) {} static inline void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) {} diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index f5c6bd2..d49399d 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -293,6 +293,7 @@ struct kvm_vm_stat { struct kvm_vcpu_stat { u32 halt_successful_poll; u32 halt_attempted_poll; + u32 halt_poll_invalid; u32 halt_wakeup; u32 hvc_exit_stat; u64 wfe_exit_stat; @@ -357,6 +358,7 @@ static inline void kvm_arch_hardware_unsetup(void) {} static inline void kvm_arch_sync_events(struct kvm *kvm) {} static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} +static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {} void kvm_arm_init_debug(void); void kvm_arm_setup_debug(struct kvm_vcpu *vcpu); diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h index 942b8f6..9a37a10 100644 --- a/arch/mips/include/asm/kvm_host.h +++ b/arch/mips/include/asm/kvm_host.h @@ -122,6 +122,7 @@ struct kvm_vcpu_stat { u32 flush_dcache_exits; u32 halt_successful_poll; u32 halt_attempted_poll; + u32 halt_poll_invalid; u32 halt_wakeup; }; @@ -812,5 +813,6 @@ static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} static inline void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) {} static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {} +static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {} #endif /* __MIPS_KVM_HOST_H__ */ diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c index 23b2094..dc052fb 100644 --- a/arch/mips/kvm/mips.c +++ b/arch/mips/kvm/mips.c @@ -56,6 +56,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { { "flush_dcache", VCPU_STAT(flush_dcache_exits), KVM_STAT_VCPU }, { "halt_successful_poll", VCPU_STAT(halt_successful_poll), KVM_STAT_VCPU }, { "halt_attempted_poll", VCPU_STAT(halt_attempted_poll), KVM_STAT_VCPU }, + { "halt_poll_invalid", VCPU_STAT(halt_poll_invalid), KVM_STAT_VCPU }, { "halt_wakeup", VCPU_STAT(halt_wakeup), KVM_STAT_VCPU }, {NULL} }; diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index a07645c..ec35af3 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -116,6 +116,7 @@ struct kvm_vcpu_stat { u32 ext_intr_exits; u32 halt_successful_poll; u32 halt_attempted_poll; + u32 halt_poll_invalid; u32 halt_wakeup; u32 dbell_exits; u32 gdbell_exits; @@ -727,5 +728,6 @@ static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} static inline void kvm_arch_exit(void) {} static inline void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) {} static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {} +static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {} #endif /* __POWERPC_KVM_HOST_H__ */ diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c index b34220d2..47018fc 100644 --- a/arch/powerpc/kvm/book3s.c +++ b/arch/powerpc/kvm/book3s.c @@ -54,6 +54,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { { "queue_intr", VCPU_STAT(queue_intr) }, { "halt_successful_poll", VCPU_STAT(halt_successful_poll), }, { "halt_attempted_poll", VCPU_STAT(halt_attempted_poll), }, + { "halt_poll_invalid", VCPU_STAT(halt_poll_invalid) }, { "halt_wakeup", VCPU_STAT(halt_wakeup) }, { "pf_storage", VCPU_STAT(pf_storage) }, { "sp_storage", VCPU_STAT(sp_storage) }, diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c index 4d66f44..4afae69 100644 --- a/arch/powerpc/kvm/booke.c +++ b/arch/powerpc/kvm/booke.c @@ -64,6 +64,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { { "ext_intr", VCPU_STAT(ext_intr_exits) }, { "halt_successful_poll", VCPU_STAT(halt_successful_poll) }, { "halt_attempted_poll", VCPU_STAT(halt_attempted_poll) }, + { "halt_poll_invalid", VCPU_STAT(halt_poll_invalid) }, { "halt_wakeup", VCPU_STAT(halt_wakeup) }, { "doorbell", VCPU_STAT(dbell_exits) }, { "guest doorbell", VCPU_STAT(gdbell_exits) }, diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index 9282ccf..53d7945 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -247,6 +247,7 @@ struct kvm_vcpu_stat { u32 exit_instruction; u32 halt_successful_poll; u32 halt_attempted_poll; + u32 halt_poll_invalid; u32 halt_wakeup; u32 instruction_lctl; u32 instruction_lctlg; @@ -696,4 +697,6 @@ static inline void kvm_arch_flush_shadow_memslot(struct kvm *kvm, static inline void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) {} static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {} +void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu); + #endif diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig index 5ea5af3..ccfe6f6 100644 --- a/arch/s390/kvm/Kconfig +++ b/arch/s390/kvm/Kconfig @@ -28,6 +28,7 @@ config KVM select HAVE_KVM_IRQCHIP select HAVE_KVM_IRQFD select HAVE_KVM_IRQ_ROUTING + select HAVE_KVM_INVALID_POLLS select SRCU select KVM_VFIO ---help--- diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index e550404..5a80af7 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -977,6 +977,11 @@ no_timer: void kvm_s390_vcpu_wakeup(struct kvm_vcpu *vcpu) { + /* + * We cannot move this into the if, as the CPU might be already + * in kvm_vcpu_block without having the waitqueue set (polling) + */ + vcpu->valid_wakeup = true; if (swait_active(&vcpu->wq)) { /* * The vcpu gave up the cpu voluntarily, mark it as a good diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index c597201..6d8ec3a 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -65,6 +65,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { { "exit_instr_and_program_int", VCPU_STAT(exit_instr_and_program) }, { "halt_successful_poll", VCPU_STAT(halt_successful_poll) }, { "halt_attempted_poll", VCPU_STAT(halt_attempted_poll) }, + { "halt_poll_invalid", VCPU_STAT(halt_poll_invalid) }, { "halt_wakeup", VCPU_STAT(halt_wakeup) }, { "instruction_lctlg", VCPU_STAT(instruction_lctlg) }, { "instruction_lctl", VCPU_STAT(instruction_lctl) }, @@ -2992,6 +2993,11 @@ static inline unsigned long nonhyp_mask(int i) return 0x0000ffffffffffffUL >> (nonhyp_fai << 4); } +void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) +{ + vcpu->valid_wakeup = false; +} + static int __init kvm_s390_init(void) { int i; diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index c66e262..c99494b 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -803,6 +803,7 @@ struct kvm_vcpu_stat { u32 halt_exits; u32 halt_successful_poll; u32 halt_attempted_poll; + u32 halt_poll_invalid; u32 halt_wakeup; u32 request_irq_exits; u32 irq_exits; @@ -1342,5 +1343,6 @@ void kvm_set_msi_irq(struct kvm_kernel_irq_routing_entry *e, static inline void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) {} static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {} +static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {} #endif /* _ASM_X86_KVM_HOST_H */ diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 6c774cd..bcef92f 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -161,6 +161,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { { "halt_exits", VCPU_STAT(halt_exits) }, { "halt_successful_poll", VCPU_STAT(halt_successful_poll) }, { "halt_attempted_poll", VCPU_STAT(halt_attempted_poll) }, + { "halt_poll_invalid", VCPU_STAT(halt_poll_invalid) }, { "halt_wakeup", VCPU_STAT(halt_wakeup) }, { "hypercalls", VCPU_STAT(hypercalls) }, { "request_irq", VCPU_STAT(request_irq_exits) }, diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 92a0229..f350dc9 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -229,6 +229,7 @@ struct kvm_vcpu { sigset_t sigset; struct kvm_vcpu_stat stat; unsigned int halt_poll_ns; + bool valid_wakeup; #ifdef CONFIG_HAS_IOMEM int mmio_needed; @@ -1196,4 +1197,18 @@ int kvm_arch_update_irqfd_routing(struct kvm *kvm, unsigned int host_irq, uint32_t guest_irq, bool set); #endif /* CONFIG_HAVE_KVM_IRQ_BYPASS */ +#ifdef CONFIG_HAVE_KVM_INVALID_POLLS +/* If we wakeup during the poll time, was it a sucessful poll? */ +static inline bool vcpu_valid_wakeup(struct kvm_vcpu *vcpu) +{ + return vcpu->valid_wakeup; +} + +#else +static inline bool vcpu_valid_wakeup(struct kvm_vcpu *vcpu) +{ + return true; +} +#endif /* CONFIG_HAVE_KVM_INVALID_POLLS */ + #endif diff --git a/include/trace/events/kvm.h b/include/trace/events/kvm.h index aa69253..526fb3d 100644 --- a/include/trace/events/kvm.h +++ b/include/trace/events/kvm.h @@ -38,22 +38,25 @@ TRACE_EVENT(kvm_userspace_exit, ); TRACE_EVENT(kvm_vcpu_wakeup, - TP_PROTO(__u64 ns, bool waited), - TP_ARGS(ns, waited), + TP_PROTO(__u64 ns, bool waited, bool valid), + TP_ARGS(ns, waited, valid), TP_STRUCT__entry( __field( __u64, ns ) __field( bool, waited ) + __field( bool, valid ) ), TP_fast_assign( __entry->ns = ns; __entry->waited = waited; + __entry->valid = valid; ), - TP_printk("%s time %lld ns", + TP_printk("%s time %lld ns, polling %s", __entry->waited ? "wait" : "poll", - __entry->ns) + __entry->ns, + __entry->valid ? "valid" : "invalid") ); #if defined(CONFIG_HAVE_KVM_IRQFD) diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig index 7a79b68..4451842 100644 --- a/virt/kvm/Kconfig +++ b/virt/kvm/Kconfig @@ -41,6 +41,9 @@ config KVM_VFIO config HAVE_KVM_ARCH_TLB_FLUSH_ALL bool +config HAVE_KVM_INVALID_POLLS + bool + config KVM_GENERIC_DIRTYLOG_READ_PROTECT bool diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index ed3d9bb..21f6498 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2028,6 +2028,8 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu) */ if (kvm_vcpu_check_block(vcpu) < 0) { ++vcpu->stat.halt_successful_poll; + if (!vcpu_valid_wakeup(vcpu)) + ++vcpu->stat.halt_poll_invalid; goto out; } cur = ktime_get(); @@ -2057,7 +2059,8 @@ out: if (block_ns <= vcpu->halt_poll_ns) ; /* we had a long block, shrink polling */ - else if (vcpu->halt_poll_ns && block_ns > halt_poll_ns) + else if (!vcpu_valid_wakeup(vcpu) || + (vcpu->halt_poll_ns && block_ns > halt_poll_ns)) shrink_halt_poll_ns(vcpu); /* we had a short halt and our poll time is too small */ else if (vcpu->halt_poll_ns < halt_poll_ns && @@ -2066,7 +2069,8 @@ out: } else vcpu->halt_poll_ns = 0; - trace_kvm_vcpu_wakeup(block_ns, waited); + trace_kvm_vcpu_wakeup(block_ns, waited, vcpu_valid_wakeup(vcpu)); + kvm_arch_vcpu_block_finish(vcpu); } EXPORT_SYMBOL_GPL(kvm_vcpu_block); -- 2.5.5 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH 1/2] KVM: halt_polling: provide a way to qualify wakeups during poll 2016-05-13 10:16 ` [PATCH 1/2] KVM: halt_polling: provide a way to qualify wakeups during poll Christian Borntraeger @ 2016-05-13 12:02 ` Paolo Bonzini 2016-05-13 12:26 ` Christian Borntraeger 2016-05-13 16:47 ` David Matlack 1 sibling, 1 reply; 8+ messages in thread From: Paolo Bonzini @ 2016-05-13 12:02 UTC (permalink / raw) To: Christian Borntraeger, Radim Krčmář Cc: KVM, Cornelia Huck, linux-s390 On 13/05/2016 12:16, Christian Borntraeger wrote: > +config HAVE_KVM_INVALID_POLLS > + bool > + I'll change the config item to HAVE_KVM_INVALID_WAKEUPS, otherwise looks good. Paolo ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 1/2] KVM: halt_polling: provide a way to qualify wakeups during poll 2016-05-13 12:02 ` Paolo Bonzini @ 2016-05-13 12:26 ` Christian Borntraeger 2016-05-13 12:29 ` Paolo Bonzini 0 siblings, 1 reply; 8+ messages in thread From: Christian Borntraeger @ 2016-05-13 12:26 UTC (permalink / raw) To: Paolo Bonzini, Radim Krčmář; +Cc: KVM, Cornelia Huck, linux-s390 On 05/13/2016 02:02 PM, Paolo Bonzini wrote: > > > On 13/05/2016 12:16, Christian Borntraeger wrote: >> +config HAVE_KVM_INVALID_POLLS >> + bool >> + > > I'll change the config item to HAVE_KVM_INVALID_WAKEUPS, otherwise looks > good. Can you do that or shall I resend as pull request? Regarding 4.7 vs. 4.8 Lets do this for 4.7. In the unlikely case that there is some bigger fallout we can still revert or fix for 2 1/2 month but it really seems to help. ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 1/2] KVM: halt_polling: provide a way to qualify wakeups during poll 2016-05-13 12:26 ` Christian Borntraeger @ 2016-05-13 12:29 ` Paolo Bonzini 0 siblings, 0 replies; 8+ messages in thread From: Paolo Bonzini @ 2016-05-13 12:29 UTC (permalink / raw) To: Christian Borntraeger, Radim Krčmář Cc: KVM, Cornelia Huck, linux-s390 On 13/05/2016 14:26, Christian Borntraeger wrote: >> > >> > On 13/05/2016 12:16, Christian Borntraeger wrote: >>> >> +config HAVE_KVM_INVALID_POLLS >>> >> + bool >>> >> + >> > >> > I'll change the config item to HAVE_KVM_INVALID_WAKEUPS, otherwise looks >> > good. > Can you do that or shall I resend as pull request? I'll do this. Paolo > Regarding 4.7 vs. 4.8 > Lets do this for 4.7. In the unlikely case that there is some bigger fallout > we can still revert or fix for 2 1/2 month but it really seems to help. > > ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 1/2] KVM: halt_polling: provide a way to qualify wakeups during poll 2016-05-13 10:16 ` [PATCH 1/2] KVM: halt_polling: provide a way to qualify wakeups during poll Christian Borntraeger 2016-05-13 12:02 ` Paolo Bonzini @ 2016-05-13 16:47 ` David Matlack 1 sibling, 0 replies; 8+ messages in thread From: David Matlack @ 2016-05-13 16:47 UTC (permalink / raw) To: Christian Borntraeger Cc: Paolo Bonzini, Radim Krčmář, KVM, Cornelia Huck, linux-s390 On Fri, May 13, 2016 at 3:16 AM, Christian Borntraeger <borntraeger@de.ibm.com> wrote: > Some wakeups should not be considered a sucessful poll. For example on > s390 I/O interrupts are usually floating, which means that _ALL_ CPUs > would be considered runnable - letting all vCPUs poll all the time for > transactional like workload, even if one vCPU would be enough. > This can result in huge CPU usage for large guests. > This patch lets architectures provide a way to qualify wakeups if they > should be considered a good/bad wakeups in regard to polls. > > For s390 the implementation will fence of halt polling for anything but > known good, single vCPU events. The s390 implementation for floating > interrupts does a wakeup for one vCPU, but the interrupt will be delivered > by whatever CPU checks first for a pending interrupt. We prefer the > woken up CPU by marking the poll of this CPU as "good" poll. > This code will also mark several other wakeup reasons like IPI or > expired timers as "good". This will of course also mark some events as > not sucessful. As KVM on z runs always as a 2nd level hypervisor, > we prefer to not poll, unless we are really sure, though. > > This patch successfully limits the CPU usage for cases like uperf 1byte > transactional ping pong workload or wakeup heavy workload like OLTP > while still providing a proper speedup. > > This also introduced a new vcpu stat "halt_poll_no_tuning" that marks > wakeups that are considered not good for polling. > > Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> > Acked-by: Radim Krčmář <rkrcmar@redhat.com> (for an earlier version) > Cc: David Matlack <dmatlack@google.com> Reviewed-by: David Matlack <dmatlack@google.com> > Cc: Wanpeng Li <kernellwp@gmail.com> > --- > arch/arm/include/asm/kvm_host.h | 2 ++ > arch/arm64/include/asm/kvm_host.h | 2 ++ > arch/mips/include/asm/kvm_host.h | 2 ++ > arch/mips/kvm/mips.c | 1 + > arch/powerpc/include/asm/kvm_host.h | 2 ++ > arch/powerpc/kvm/book3s.c | 1 + > arch/powerpc/kvm/booke.c | 1 + > arch/s390/include/asm/kvm_host.h | 3 +++ > arch/s390/kvm/Kconfig | 1 + > arch/s390/kvm/interrupt.c | 5 +++++ > arch/s390/kvm/kvm-s390.c | 6 ++++++ > arch/x86/include/asm/kvm_host.h | 2 ++ > arch/x86/kvm/x86.c | 1 + > include/linux/kvm_host.h | 15 +++++++++++++++ > include/trace/events/kvm.h | 11 +++++++---- > virt/kvm/Kconfig | 3 +++ > virt/kvm/kvm_main.c | 8 ++++++-- > 17 files changed, 60 insertions(+), 6 deletions(-) > > diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h > index 3850701..4cd8732 100644 > --- a/arch/arm/include/asm/kvm_host.h > +++ b/arch/arm/include/asm/kvm_host.h > @@ -187,6 +187,7 @@ struct kvm_vm_stat { > struct kvm_vcpu_stat { > u32 halt_successful_poll; > u32 halt_attempted_poll; > + u32 halt_poll_invalid; > u32 halt_wakeup; > u32 hvc_exit_stat; > u64 wfe_exit_stat; > @@ -282,6 +283,7 @@ static inline void kvm_arch_hardware_unsetup(void) {} > static inline void kvm_arch_sync_events(struct kvm *kvm) {} > static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} > static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} > +static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {} > > static inline void kvm_arm_init_debug(void) {} > static inline void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) {} > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index f5c6bd2..d49399d 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -293,6 +293,7 @@ struct kvm_vm_stat { > struct kvm_vcpu_stat { > u32 halt_successful_poll; > u32 halt_attempted_poll; > + u32 halt_poll_invalid; > u32 halt_wakeup; > u32 hvc_exit_stat; > u64 wfe_exit_stat; > @@ -357,6 +358,7 @@ static inline void kvm_arch_hardware_unsetup(void) {} > static inline void kvm_arch_sync_events(struct kvm *kvm) {} > static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} > static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} > +static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {} > > void kvm_arm_init_debug(void); > void kvm_arm_setup_debug(struct kvm_vcpu *vcpu); > diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h > index 942b8f6..9a37a10 100644 > --- a/arch/mips/include/asm/kvm_host.h > +++ b/arch/mips/include/asm/kvm_host.h > @@ -122,6 +122,7 @@ struct kvm_vcpu_stat { > u32 flush_dcache_exits; > u32 halt_successful_poll; > u32 halt_attempted_poll; > + u32 halt_poll_invalid; > u32 halt_wakeup; > }; > > @@ -812,5 +813,6 @@ static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} > static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} > static inline void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) {} > static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {} > +static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {} > > #endif /* __MIPS_KVM_HOST_H__ */ > diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c > index 23b2094..dc052fb 100644 > --- a/arch/mips/kvm/mips.c > +++ b/arch/mips/kvm/mips.c > @@ -56,6 +56,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { > { "flush_dcache", VCPU_STAT(flush_dcache_exits), KVM_STAT_VCPU }, > { "halt_successful_poll", VCPU_STAT(halt_successful_poll), KVM_STAT_VCPU }, > { "halt_attempted_poll", VCPU_STAT(halt_attempted_poll), KVM_STAT_VCPU }, > + { "halt_poll_invalid", VCPU_STAT(halt_poll_invalid), KVM_STAT_VCPU }, > { "halt_wakeup", VCPU_STAT(halt_wakeup), KVM_STAT_VCPU }, > {NULL} > }; > diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h > index a07645c..ec35af3 100644 > --- a/arch/powerpc/include/asm/kvm_host.h > +++ b/arch/powerpc/include/asm/kvm_host.h > @@ -116,6 +116,7 @@ struct kvm_vcpu_stat { > u32 ext_intr_exits; > u32 halt_successful_poll; > u32 halt_attempted_poll; > + u32 halt_poll_invalid; > u32 halt_wakeup; > u32 dbell_exits; > u32 gdbell_exits; > @@ -727,5 +728,6 @@ static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} > static inline void kvm_arch_exit(void) {} > static inline void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) {} > static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {} > +static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {} > > #endif /* __POWERPC_KVM_HOST_H__ */ > diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c > index b34220d2..47018fc 100644 > --- a/arch/powerpc/kvm/book3s.c > +++ b/arch/powerpc/kvm/book3s.c > @@ -54,6 +54,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { > { "queue_intr", VCPU_STAT(queue_intr) }, > { "halt_successful_poll", VCPU_STAT(halt_successful_poll), }, > { "halt_attempted_poll", VCPU_STAT(halt_attempted_poll), }, > + { "halt_poll_invalid", VCPU_STAT(halt_poll_invalid) }, > { "halt_wakeup", VCPU_STAT(halt_wakeup) }, > { "pf_storage", VCPU_STAT(pf_storage) }, > { "sp_storage", VCPU_STAT(sp_storage) }, > diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c > index 4d66f44..4afae69 100644 > --- a/arch/powerpc/kvm/booke.c > +++ b/arch/powerpc/kvm/booke.c > @@ -64,6 +64,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { > { "ext_intr", VCPU_STAT(ext_intr_exits) }, > { "halt_successful_poll", VCPU_STAT(halt_successful_poll) }, > { "halt_attempted_poll", VCPU_STAT(halt_attempted_poll) }, > + { "halt_poll_invalid", VCPU_STAT(halt_poll_invalid) }, > { "halt_wakeup", VCPU_STAT(halt_wakeup) }, > { "doorbell", VCPU_STAT(dbell_exits) }, > { "guest doorbell", VCPU_STAT(gdbell_exits) }, > diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h > index 9282ccf..53d7945 100644 > --- a/arch/s390/include/asm/kvm_host.h > +++ b/arch/s390/include/asm/kvm_host.h > @@ -247,6 +247,7 @@ struct kvm_vcpu_stat { > u32 exit_instruction; > u32 halt_successful_poll; > u32 halt_attempted_poll; > + u32 halt_poll_invalid; > u32 halt_wakeup; > u32 instruction_lctl; > u32 instruction_lctlg; > @@ -696,4 +697,6 @@ static inline void kvm_arch_flush_shadow_memslot(struct kvm *kvm, > static inline void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) {} > static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {} > > +void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu); > + > #endif > diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig > index 5ea5af3..ccfe6f6 100644 > --- a/arch/s390/kvm/Kconfig > +++ b/arch/s390/kvm/Kconfig > @@ -28,6 +28,7 @@ config KVM > select HAVE_KVM_IRQCHIP > select HAVE_KVM_IRQFD > select HAVE_KVM_IRQ_ROUTING > + select HAVE_KVM_INVALID_POLLS > select SRCU > select KVM_VFIO > ---help--- > diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c > index e550404..5a80af7 100644 > --- a/arch/s390/kvm/interrupt.c > +++ b/arch/s390/kvm/interrupt.c > @@ -977,6 +977,11 @@ no_timer: > > void kvm_s390_vcpu_wakeup(struct kvm_vcpu *vcpu) > { > + /* > + * We cannot move this into the if, as the CPU might be already > + * in kvm_vcpu_block without having the waitqueue set (polling) > + */ > + vcpu->valid_wakeup = true; > if (swait_active(&vcpu->wq)) { > /* > * The vcpu gave up the cpu voluntarily, mark it as a good > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > index c597201..6d8ec3a 100644 > --- a/arch/s390/kvm/kvm-s390.c > +++ b/arch/s390/kvm/kvm-s390.c > @@ -65,6 +65,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { > { "exit_instr_and_program_int", VCPU_STAT(exit_instr_and_program) }, > { "halt_successful_poll", VCPU_STAT(halt_successful_poll) }, > { "halt_attempted_poll", VCPU_STAT(halt_attempted_poll) }, > + { "halt_poll_invalid", VCPU_STAT(halt_poll_invalid) }, > { "halt_wakeup", VCPU_STAT(halt_wakeup) }, > { "instruction_lctlg", VCPU_STAT(instruction_lctlg) }, > { "instruction_lctl", VCPU_STAT(instruction_lctl) }, > @@ -2992,6 +2993,11 @@ static inline unsigned long nonhyp_mask(int i) > return 0x0000ffffffffffffUL >> (nonhyp_fai << 4); > } > > +void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) > +{ > + vcpu->valid_wakeup = false; > +} > + > static int __init kvm_s390_init(void) > { > int i; > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index c66e262..c99494b 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -803,6 +803,7 @@ struct kvm_vcpu_stat { > u32 halt_exits; > u32 halt_successful_poll; > u32 halt_attempted_poll; > + u32 halt_poll_invalid; > u32 halt_wakeup; > u32 request_irq_exits; > u32 irq_exits; > @@ -1342,5 +1343,6 @@ void kvm_set_msi_irq(struct kvm_kernel_irq_routing_entry *e, > > static inline void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) {} > static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {} > +static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {} > > #endif /* _ASM_X86_KVM_HOST_H */ > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 6c774cd..bcef92f 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -161,6 +161,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { > { "halt_exits", VCPU_STAT(halt_exits) }, > { "halt_successful_poll", VCPU_STAT(halt_successful_poll) }, > { "halt_attempted_poll", VCPU_STAT(halt_attempted_poll) }, > + { "halt_poll_invalid", VCPU_STAT(halt_poll_invalid) }, > { "halt_wakeup", VCPU_STAT(halt_wakeup) }, > { "hypercalls", VCPU_STAT(hypercalls) }, > { "request_irq", VCPU_STAT(request_irq_exits) }, > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index 92a0229..f350dc9 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -229,6 +229,7 @@ struct kvm_vcpu { > sigset_t sigset; > struct kvm_vcpu_stat stat; > unsigned int halt_poll_ns; > + bool valid_wakeup; > > #ifdef CONFIG_HAS_IOMEM > int mmio_needed; > @@ -1196,4 +1197,18 @@ int kvm_arch_update_irqfd_routing(struct kvm *kvm, unsigned int host_irq, > uint32_t guest_irq, bool set); > #endif /* CONFIG_HAVE_KVM_IRQ_BYPASS */ > > +#ifdef CONFIG_HAVE_KVM_INVALID_POLLS > +/* If we wakeup during the poll time, was it a sucessful poll? */ > +static inline bool vcpu_valid_wakeup(struct kvm_vcpu *vcpu) > +{ > + return vcpu->valid_wakeup; > +} > + > +#else > +static inline bool vcpu_valid_wakeup(struct kvm_vcpu *vcpu) > +{ > + return true; > +} > +#endif /* CONFIG_HAVE_KVM_INVALID_POLLS */ > + > #endif > diff --git a/include/trace/events/kvm.h b/include/trace/events/kvm.h > index aa69253..526fb3d 100644 > --- a/include/trace/events/kvm.h > +++ b/include/trace/events/kvm.h > @@ -38,22 +38,25 @@ TRACE_EVENT(kvm_userspace_exit, > ); > > TRACE_EVENT(kvm_vcpu_wakeup, > - TP_PROTO(__u64 ns, bool waited), > - TP_ARGS(ns, waited), > + TP_PROTO(__u64 ns, bool waited, bool valid), > + TP_ARGS(ns, waited, valid), > > TP_STRUCT__entry( > __field( __u64, ns ) > __field( bool, waited ) > + __field( bool, valid ) > ), > > TP_fast_assign( > __entry->ns = ns; > __entry->waited = waited; > + __entry->valid = valid; > ), > > - TP_printk("%s time %lld ns", > + TP_printk("%s time %lld ns, polling %s", > __entry->waited ? "wait" : "poll", > - __entry->ns) > + __entry->ns, > + __entry->valid ? "valid" : "invalid") > ); > > #if defined(CONFIG_HAVE_KVM_IRQFD) > diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig > index 7a79b68..4451842 100644 > --- a/virt/kvm/Kconfig > +++ b/virt/kvm/Kconfig > @@ -41,6 +41,9 @@ config KVM_VFIO > config HAVE_KVM_ARCH_TLB_FLUSH_ALL > bool > > +config HAVE_KVM_INVALID_POLLS > + bool > + > config KVM_GENERIC_DIRTYLOG_READ_PROTECT > bool > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index ed3d9bb..21f6498 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -2028,6 +2028,8 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu) > */ > if (kvm_vcpu_check_block(vcpu) < 0) { > ++vcpu->stat.halt_successful_poll; > + if (!vcpu_valid_wakeup(vcpu)) > + ++vcpu->stat.halt_poll_invalid; > goto out; > } > cur = ktime_get(); > @@ -2057,7 +2059,8 @@ out: > if (block_ns <= vcpu->halt_poll_ns) > ; > /* we had a long block, shrink polling */ > - else if (vcpu->halt_poll_ns && block_ns > halt_poll_ns) > + else if (!vcpu_valid_wakeup(vcpu) || > + (vcpu->halt_poll_ns && block_ns > halt_poll_ns)) > shrink_halt_poll_ns(vcpu); > /* we had a short halt and our poll time is too small */ > else if (vcpu->halt_poll_ns < halt_poll_ns && > @@ -2066,7 +2069,8 @@ out: > } else > vcpu->halt_poll_ns = 0; > > - trace_kvm_vcpu_wakeup(block_ns, waited); > + trace_kvm_vcpu_wakeup(block_ns, waited, vcpu_valid_wakeup(vcpu)); > + kvm_arch_vcpu_block_finish(vcpu); > } > EXPORT_SYMBOL_GPL(kvm_vcpu_block); > > -- > 2.5.5 > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html ^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH 2/2] KVM: s390: set halt polling to 80 microseconds 2016-05-13 10:16 [PATCH 0/2] halt polling changes Christian Borntraeger 2016-05-13 10:16 ` [PATCH 1/2] KVM: halt_polling: provide a way to qualify wakeups during poll Christian Borntraeger @ 2016-05-13 10:16 ` Christian Borntraeger 2016-05-13 12:03 ` [PATCH 0/2] halt polling changes Paolo Bonzini 2 siblings, 0 replies; 8+ messages in thread From: Christian Borntraeger @ 2016-05-13 10:16 UTC (permalink / raw) To: Paolo Bonzini, Radim Krčmář Cc: KVM, Cornelia Huck, linux-s390, Christian Borntraeger on s390 we disabled the halt polling with commit 920552b213e3 ("KVM: disable halt_poll_ns as default for s390x"), as floating interrupts would let all CPUs have a successful poll, resulting in much higher CPU usage (on otherwise idle systems). With the improved selection of polls we can now retry halt polling. Performance measurements with different choices like 25,50,80,100,200 microseconds showed that 80 microseconds seems to improve several cases without increasing the CPU costs too much. Higher values would improve the performance even more but increased the cpu time as well. So let's start small and use this value of 80 microseconds on s390 until we have a better understanding of cost/benefit of higher values. Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> --- arch/s390/include/asm/kvm_host.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index 53d7945..37b9017 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -38,7 +38,7 @@ */ #define KVM_NR_IRQCHIPS 1 #define KVM_IRQCHIP_NUM_PINS 4096 -#define KVM_HALT_POLL_NS_DEFAULT 0 +#define KVM_HALT_POLL_NS_DEFAULT 80000 /* s390-specific vcpu->requests bit members */ #define KVM_REQ_ENABLE_IBS 8 -- 2.5.5 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH 0/2] halt polling changes 2016-05-13 10:16 [PATCH 0/2] halt polling changes Christian Borntraeger 2016-05-13 10:16 ` [PATCH 1/2] KVM: halt_polling: provide a way to qualify wakeups during poll Christian Borntraeger 2016-05-13 10:16 ` [PATCH 2/2] KVM: s390: set halt polling to 80 microseconds Christian Borntraeger @ 2016-05-13 12:03 ` Paolo Bonzini 2 siblings, 0 replies; 8+ messages in thread From: Paolo Bonzini @ 2016-05-13 12:03 UTC (permalink / raw) To: Christian Borntraeger, Radim Krčmář Cc: KVM, Cornelia Huck, linux-s390 On 13/05/2016 12:16, Christian Borntraeger wrote: > Paolo, Radim, > > here is the updated version of halt polling patches that improves s390. > Lots of uperf/iperf measurements showed several improvements without > things going over board. So I would like to go with this approach. > Patch 1 was several days in linux-next (I just added Radims ACk > from an earlier version), so it does not seem to break mips,arm,power and > x86. Still ok for 4.7 or shall I defer this for 4.8? Your call, it's just s390 stuff. :) So I will commit for 4.7. Thanks, Paolo > Christian Borntraeger (2): > KVM: halt_polling: provide a way to qualify wakeups during poll > KVM: s390: set halt polling to 80 microseconds > > arch/arm/include/asm/kvm_host.h | 2 ++ > arch/arm64/include/asm/kvm_host.h | 2 ++ > arch/mips/include/asm/kvm_host.h | 2 ++ > arch/mips/kvm/mips.c | 1 + > arch/powerpc/include/asm/kvm_host.h | 2 ++ > arch/powerpc/kvm/book3s.c | 1 + > arch/powerpc/kvm/booke.c | 1 + > arch/s390/include/asm/kvm_host.h | 5 ++++- > arch/s390/kvm/Kconfig | 1 + > arch/s390/kvm/interrupt.c | 5 +++++ > arch/s390/kvm/kvm-s390.c | 6 ++++++ > arch/x86/include/asm/kvm_host.h | 2 ++ > arch/x86/kvm/x86.c | 1 + > include/linux/kvm_host.h | 15 +++++++++++++++ > include/trace/events/kvm.h | 11 +++++++---- > virt/kvm/Kconfig | 3 +++ > virt/kvm/kvm_main.c | 8 ++++++-- > 17 files changed, 61 insertions(+), 7 deletions(-) > ^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2016-05-13 16:47 UTC | newest] Thread overview: 8+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2016-05-13 10:16 [PATCH 0/2] halt polling changes Christian Borntraeger 2016-05-13 10:16 ` [PATCH 1/2] KVM: halt_polling: provide a way to qualify wakeups during poll Christian Borntraeger 2016-05-13 12:02 ` Paolo Bonzini 2016-05-13 12:26 ` Christian Borntraeger 2016-05-13 12:29 ` Paolo Bonzini 2016-05-13 16:47 ` David Matlack 2016-05-13 10:16 ` [PATCH 2/2] KVM: s390: set halt polling to 80 microseconds Christian Borntraeger 2016-05-13 12:03 ` [PATCH 0/2] halt polling changes Paolo Bonzini
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