similar to: [PATCH RFC v3 0/6] x86/idle: add halt poll support

From: Quan Xu <quan.xu0 at gmail.com> Some latency-intensive workload have seen 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

From: Quan Xu <quan.xu0 at gmail.com> Some latency-intensive workload have seen 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

From: Yang Zhang <yang.zhang.wz at gmail.com> Some latency-intensive workload have seen 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

From: Yang Zhang <yang.zhang.wz at gmail.com> Some latency-intensive workload have seen 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

On 2017/11/14 15:12, Wanpeng Li wrote: > 2017-11-14 15:02 GMT+08:00 Quan Xu <quan.xu0 at gmail.com>: >> >> On 2017/11/13 18:53, Juergen Gross wrote: >>> On 13/11/17 11:06, Quan Xu wrote: >>>> From: Quan Xu <quan.xu0 at gmail.com> >>>> >>>> So far, pv_idle_ops.poll is the only ops for pv_idle. .poll is called >>>>

On 2017/11/14 15:12, Wanpeng Li wrote: > 2017-11-14 15:02 GMT+08:00 Quan Xu <quan.xu0 at gmail.com>: >> >> On 2017/11/13 18:53, Juergen Gross wrote: >>> On 13/11/17 11:06, Quan Xu wrote: >>>> From: Quan Xu <quan.xu0 at gmail.com> >>>> >>>> So far, pv_idle_ops.poll is the only ops for pv_idle. .poll is called >>>>

On 2017/11/13 18:53, Juergen Gross wrote: > On 13/11/17 11:06, Quan Xu wrote: >> From: Quan Xu <quan.xu0 at gmail.com> >> >> So far, pv_idle_ops.poll is the only ops for pv_idle. .poll is called >> in idle path which will poll for a while before we enter the real idle >> state. >> >> In virtualization, idle path includes several heavy operations

On 2017/11/13 18:53, Juergen Gross wrote: > On 13/11/17 11:06, Quan Xu wrote: >> From: Quan Xu <quan.xu0 at gmail.com> >> >> So far, pv_idle_ops.poll is the only ops for pv_idle. .poll is called >> in idle path which will poll for a while before we enter the real idle >> state. >> >> In virtualization, idle path includes several heavy operations

On 2017/11/14 15:30, Juergen Gross wrote: > On 14/11/17 08:02, Quan Xu wrote: >> >> On 2017/11/13 18:53, Juergen Gross wrote: >>> On 13/11/17 11:06, Quan Xu wrote: >>>> From: Quan Xu <quan.xu0 at gmail.com> >>>> >>>> So far, pv_idle_ops.poll is the only ops for pv_idle. .poll is called >>>> in idle path which will poll

On 2017/11/14 15:30, Juergen Gross wrote: > On 14/11/17 08:02, Quan Xu wrote: >> >> On 2017/11/13 18:53, Juergen Gross wrote: >>> On 13/11/17 11:06, Quan Xu wrote: >>>> From: Quan Xu <quan.xu0 at gmail.com> >>>> >>>> So far, pv_idle_ops.poll is the only ops for pv_idle. .poll is called >>>> in idle path which will poll

On 2017/11/14 18:27, Juergen Gross wrote: > On 14/11/17 10:38, Quan Xu wrote: >> >> On 2017/11/14 15:30, Juergen Gross wrote: >>> On 14/11/17 08:02, Quan Xu wrote: >>>> On 2017/11/13 18:53, Juergen Gross wrote: >>>>> On 13/11/17 11:06, Quan Xu wrote: >>>>>> From: Quan Xu <quan.xu0 at gmail.com> >>>>>>

On 2017/11/14 18:27, Juergen Gross wrote: > On 14/11/17 10:38, Quan Xu wrote: >> >> On 2017/11/14 15:30, Juergen Gross wrote: >>> On 14/11/17 08:02, Quan Xu wrote: >>>> On 2017/11/13 18:53, Juergen Gross wrote: >>>>> On 13/11/17 11:06, Quan Xu wrote: >>>>>> From: Quan Xu <quan.xu0 at gmail.com> >>>>>>

From: Quan Xu <quan.xu0 at gmail.com> So far, pv_idle_ops.poll is the only ops for pv_idle. .poll is called in idle path which will poll for a while before we enter the real idle state. In virtualization, idle path includes several heavy operations includes timer access(LAPIC timer or TSC deadline timer) which will hurt performance especially for latency intensive workload like message

2017-11-14 16:15 GMT+08:00 Quan Xu <quan.xu0 at gmail.com>: > > > On 2017/11/14 15:12, Wanpeng Li wrote: >> >> 2017-11-14 15:02 GMT+08:00 Quan Xu <quan.xu0 at gmail.com>: >>> >>> >>> On 2017/11/13 18:53, Juergen Gross wrote: >>>> >>>> On 13/11/17 11:06, Quan Xu wrote: >>>>> >>>>> From:

From: Quan Xu <quan.xu0 at gmail.com> To reduce the cost of poll, we introduce three sysctl to control the poll time when running as a virtual machine with paravirt. Signed-off-by: Yang Zhang <yang.zhang.wz at gmail.com> Signed-off-by: Quan Xu <quan.xu0 at gmail.com> --- Documentation/sysctl/kernel.txt | 35 +++++++++++++++++++++++++++++++++++ arch/x86/kernel/paravirt.c

From: Quan Xu <quan.xu0 at gmail.com> To reduce the cost of poll, we introduce three sysctl to control the poll time when running as a virtual machine with paravirt. Signed-off-by: Yang Zhang <yang.zhang.wz at gmail.com> Signed-off-by: Quan Xu <quan.xu0 at gmail.com> --- Documentation/sysctl/kernel.txt | 35 +++++++++++++++++++++++++++++++++++ arch/x86/kernel/paravirt.c

2017-11-14 15:02 GMT+08:00 Quan Xu <quan.xu0 at gmail.com>: > > > On 2017/11/13 18:53, Juergen Gross wrote: >> >> On 13/11/17 11:06, Quan Xu wrote: >>> >>> From: Quan Xu <quan.xu0 at gmail.com> >>> >>> So far, pv_idle_ops.poll is the only ops for pv_idle. .poll is called >>> in idle path which will poll for a while

From: Yang Zhang <yang.zhang.wz at gmail.com> Implement a generic idle poll which resembles the functionality found in arch/. Provide weak arch_cpu_idle_poll function which can be overridden by the architecture code if needed. Interrupts arrive which may not cause a reschedule in idle loops. In KVM guest, this costs several VM-exit/VM-entry cycles, VM-entry for interrupts and VM-exit

On 14/11/17 08:02, Quan Xu wrote: > > > On 2017/11/13 18:53, Juergen Gross wrote: >> On 13/11/17 11:06, Quan Xu wrote: >>> From: Quan Xu <quan.xu0 at gmail.com> >>> >>> So far, pv_idle_ops.poll is the only ops for pv_idle. .poll is called >>> in idle path which will poll for a while before we enter the real idle >>> state.

On 2017/11/13 23:08, Ingo Molnar wrote: > * Quan Xu <quan.xu04 at gmail.com> wrote: > >> From: Quan Xu <quan.xu0 at gmail.com> >> >> To reduce the cost of poll, we introduce three sysctl to control the >> poll time when running as a virtual machine with paravirt. >> >> Signed-off-by: Yang Zhang <yang.zhang.wz at gmail.com> >>