2017-06-22 19:22 GMT+08:00 root <yang.zhang.wz@xxxxxxxxx>: > From: Yang Zhang <yang.zhang.wz@xxxxxxxxx> > > 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. 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 >
