Messages in this thread | | | Subject | Re: [PATCH 0/2] x86/idle: add halt poll support | From | Yang Zhang <> | Date | Fri, 23 Jun 2017 12:08:16 +0800 |
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On 2017/6/22 19:50, Wanpeng Li wrote: > 2017-06-22 19:22 GMT+08:00 root <yang.zhang.wz@gmail.com>: >> From: Yang Zhang <yang.zhang.wz@gmail.com> >> >> Some latency-intensive workload will see obviously performance >> drop when running inside VM. The main reason is that the overhead >> is amplified when running inside VM. The most cost i have seen is >> inside idle path. >> This patch introduces a new mechanism to poll for a while before >> entering idle state. If schedule is needed during poll, then we >> don't need to goes through the heavy overhead path. >> >> Here is the data i get when running benchmark contextswitch >> (https://github.com/tsuna/contextswitch) >> before patch: >> 2000000 process context switches in 4822613801ns (2411.3ns/ctxsw) >> after patch: >> 2000000 process context switches in 3584098241ns (1792.0ns/ctxsw) > > If you test this after disabling the adaptive halt-polling in kvm? > What's the performance data of w/ this patchset and w/o the adaptive > halt-polling in kvm, and w/o this patchset and w/ the adaptive > halt-polling in kvm? In addition, both linux and windows guests can > get benefit as we have already done this in kvm.
I will provide more data in next version. But it doesn't conflict with current halt polling inside kvm. This is just another enhancement.
> > Regards, > Wanpeng Li > >> Yang Zhang (2): >> x86/idle: add halt poll for halt idle >> x86/idle: use dynamic halt poll >> >> Documentation/sysctl/kernel.txt | 24 ++++++++++ >> arch/x86/include/asm/processor.h | 6 +++ >> arch/x86/kernel/apic/apic.c | 6 +++ >> arch/x86/kernel/apic/vector.c | 1 + >> arch/x86/kernel/cpu/mcheck/mce_amd.c | 2 + >> arch/x86/kernel/cpu/mcheck/therm_throt.c | 2 + >> arch/x86/kernel/cpu/mcheck/threshold.c | 2 + >> arch/x86/kernel/irq.c | 5 ++ >> arch/x86/kernel/irq_work.c | 2 + >> arch/x86/kernel/process.c | 80 ++++++++++++++++++++++++++++++++ >> arch/x86/kernel/smp.c | 6 +++ >> include/linux/kernel.h | 5 ++ >> kernel/sched/idle.c | 3 ++ >> kernel/sysctl.c | 23 +++++++++ >> 14 files changed, 167 insertions(+) >> >> -- >> 1.8.3.1 >>
-- Yang Alibaba Cloud Computing
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