search for: arch_cpu_idle_poll

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 immediately. Also this becomes more expensive than bare metal. Add a...

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 Wed, 15 Nov 2017, Peter Zijlstra wrote: > On Mon, Nov 13, 2017 at 06:06:02PM +0800, Quan Xu wrote: > > 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. > > No, we want less of those magic hooks, not more. > > > Interrupts arrive which may not cause a reschedule in idle loops. > > In KVM guest, this costs several VM-exit/VM-entry cycles, VM-entry &...

On Wed, 15 Nov 2017, Peter Zijlstra wrote: > On Mon, Nov 13, 2017 at 06:06:02PM +0800, Quan Xu wrote: > > 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. > > No, we want less of those magic hooks, not more. > > > Interrupts arrive which may not cause a reschedule in idle loops. > > In KVM guest, this costs several VM-exit/VM-entry cycles, VM-entry &...

...wrote: >> >>> On Mon, Nov 13, 2017 at 06:06:02PM +0800, Quan Xu wrote: >>>> 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. >>> No, we want less of those magic hooks, not more. >>> >>>> Interrupts arrive which may not cause a reschedule in idle loops. >>>> In KVM guest, this costs several VM-ex...

...wrote: >> >>> On Mon, Nov 13, 2017 at 06:06:02PM +0800, Quan Xu wrote: >>>> 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. >>> No, we want less of those magic hooks, not more. >>> >>>> Interrupts arrive which may not cause a reschedule in idle loops. >>>> In KVM guest, this costs several VM-ex...

On Mon, Nov 13, 2017 at 06:06:02PM +0800, Quan Xu wrote: > 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. No, we want less of those magic hooks, not more. > 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 Mon, Nov 13, 2017 at 06:06:02PM +0800, Quan Xu wrote: >>>>> 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. >>>> No, we want less of those magic hooks, not more. >>>> >>>>> Interrupts arrive which may not cause a reschedule in idle loops. >>>>> In KVM guest, this...

...Nov 2017, Peter Zijlstra wrote: > >> On Mon, Nov 13, 2017 at 06:06:02PM +0800, Quan Xu wrote: >>> 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. >> No, we want less of those magic hooks, not more. >> >>> Interrupts arrive which may not cause a reschedule in idle loops. >>> In KVM guest, this costs several VM-exit/VM-entry cycles,...