Re: [PATCH 25/32] sched: introduce the finish_arch_pre_lock_switch() scheduler hook

From	David Carrillo-Cisneros <davidcc@google.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 25/32] sched: introduce the finish_arch_pre_lock_switch() scheduler hook
Date	2016-04-29 23:00 +0200
Message-ID	<rtnG2-3Ts-13@gated-at.bofh.it> (permalink)
References	(1 earlier) <rt8xl-8qy-35@gated-at.bofh.it> <rtcrg-2XJ-1@gated-at.bofh.it> <rtlEe-2fj-3@gated-at.bofh.it> <rtlEe-2fj-1@gated-at.bofh.it> <rtnd0-3HL-21@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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That's a possibility, although it will increase the distance between
pmu->add for other perf events and the effective time that CQM
monitoring starts.

On Fri, Apr 29, 2016 at 1:21 PM, Vikas Shivappa
<vikas.shivappa@linux.intel.com> wrote:
>
>
> On Fri, 29 Apr 2016, David Carrillo-Cisneros wrote:
>
>> (Re-sending in plain text)
>>
>> This hook is used in the following patch in the series to write to
>> PQR_ASSOC_MSR, a msr that is utilized both by CQM/CMT and by CAT.
>> Since CAT is not dependent on perf, I created this hook to start CQM
>> monitoring right after other events start while keeping it independent
>> of perf. The idea is to have future versions of CAT to also rely on
>> this hook.
>
>
> CAT did the msr write in switch_to as Peter did not want a new hook to be
> used. Same could be done here.
>
> Thanks,
> Vikas
>
>
>>
>> On Fri, Apr 29, 2016 at 11:05 AM, David Carrillo-Cisneros
>> <davidcc@google.com> wrote:
>>>
>>> This hook is used in the following patch in the series to write to
>>> PQR_ASSOC_MSR, a msr that is utilized both by CQM/CMT and by CAT. Since
>>> CAT
>>> is not dependent on perf, I created this hook to start CQM monitoring
>>> right
>>> after other events start while keeping it independent of perf. The idea
>>> is
>>> to have future versions of CAT to also rely on this hook.
>>>
>>> On Fri, Apr 29, 2016 at 1:52 AM Peter Zijlstra <peterz@infradead.org>
>>> wrote:
>>>>
>>>>
>>>> On Thu, Apr 28, 2016 at 09:43:31PM -0700, David Carrillo-Cisneros wrote:
>>>>>
>>>>> This hook allows architecture specific code to be called at the end of
>>>>> the task switch and after perf_events' context switch but before the
>>>>> scheduler lock is released.
>>>>>
>>>>> The specific use case in this series is to avoid multiple writes to a
>>>>> slow
>>>>> MSR until all functions which modify such register in task switch have
>>>>> finished.
>>>>
>>>>
>>>> Yeah, no. This really need way more justification. Why can't you use the
>>>> regular perf sched-in stuff for CQM?
>>
>>
>

Thread

[PATCH 00/32] 2nd Iteration of Cache QoS Monitoring support. David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 06:50 +0200
  [PATCH 01/32] perf/x86/intel/cqm: temporarily remove MBM from CQM and cleanup David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 06:50 +0200
    Re: [PATCH 01/32] perf/x86/intel/cqm: temporarily remove MBM from  CQM and cleanup Vikas Shivappa <vikas.shivappa@linux.intel.com> - 2016-04-29 22:30 +0200
  [PATCH 24/32] perf/x86/intel/cqm: use PERF_INACTIVE_*_READ_* flags in CQM David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 06:50 +0200
  [PATCH 25/32] sched: introduce the finish_arch_pre_lock_switch() scheduler hook David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 06:50 +0200
    Re: [PATCH 25/32] sched: introduce the finish_arch_pre_lock_switch()  scheduler hook Peter Zijlstra <peterz@infradead.org> - 2016-04-29 11:00 +0200
      Re: [PATCH 25/32] sched: introduce the finish_arch_pre_lock_switch()  scheduler hook David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 20:50 +0200
        Re: [PATCH 25/32] sched: introduce the finish_arch_pre_lock_switch()  scheduler hook Vikas Shivappa <vikas.shivappa@linux.intel.com> - 2016-04-29 22:30 +0200
          Re: [PATCH 25/32] sched: introduce the finish_arch_pre_lock_switch()  scheduler hook David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 23:00 +0200
  [PATCH 14/32] perf/x86/intel/cqm: add preallocation of anodes David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 06:50 +0200
  [PATCH 32/32] perf/stat: revamp error handling for snapshot and per_pkg events David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 06:50 +0200
  [PATCH 09/32] perf/x86/intel/cqm: add per-package RMIDs, data and locks David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 06:50 +0200
    Re: [PATCH 09/32] perf/x86/intel/cqm: add per-package RMIDs, data  and locks Vikas Shivappa <vikas.shivappa@linux.intel.com> - 2016-04-29 23:00 +0200
  [PATCH 29/32] perf,perf/x86,perf/powerpc,perf/arm,perf/*: add int error return to pmu::read David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 06:50 +0200
  [PATCH 06/32] x86/intel,cqm: add CONFIG_INTEL_RDT configuration flag and refactor PQR David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 06:50 +0200
  [PATCH 15/32] perf/core: add hooks to expose architecture specific features in perf_cgroup David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 07:00 +0200
  [PATCH 18/32] perf/x86/intel/cqm: use pmu::event_terminate David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 07:00 +0200
  [PATCH 16/32] perf/x86/intel/cqm: add cgroup support David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 07:00 +0200
  [PATCH 17/32] perf/core: adding pmu::event_terminate David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 07:00 +0200
  [PATCH 05/32] perf/core: remove unused pmu->count David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 07:00 +0200
  [PATCH 04/32] perf/x86/intel/cqm: make read of RMIDs per package (Temporal) David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 07:00 +0200
  [PATCH 11/32] perf/x86/intel/cqm: (I)state and limbo prmids David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 07:00 +0200
  [PATCH 12/32] perf/x86/intel/cqm: add per-package RMID rotation David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 07:00 +0200
  [PATCH 08/32] perf/x86/intel/cqm: prepare for next patches David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 07:00 +0200
    Re: [PATCH 08/32] perf/x86/intel/cqm: prepare for next patches Peter Zijlstra <peterz@infradead.org> - 2016-04-29 11:20 +0200
  [PATCH 07/32] perf/x86/intel/cqm: separate CQM PMU's attributes from x86 PMU David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 07:00 +0200
  [PATCH 19/32] perf/core: introduce PMU event flag PERF_CGROUP_NO_RECURSION David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 07:00 +0200
  [PATCH 10/32] perf/x86/intel/cqm: basic RMID hierarchy with per package rmids David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 07:00 +0200
  Re: [PATCH 00/32] 2nd Iteration of Cache QoS Monitoring support. Vikas Shivappa <vikas.shivappa@linux.intel.com> - 2016-04-29 23:10 +0200
    Re: [PATCH 00/32] 2nd Iteration of Cache QoS Monitoring support. David Carrillo-Cisneros <davidcc@google.com> - 2016-04-29 23:20 +0200

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