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From: Randy Dunlap <rdunlap@infradead.org>
To: Johannes Weiner <hannes@cmpxchg.org>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-block@vger.kernel.org, cgroups@vger.kernel.org
Cc: Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Andrew Morton <akpm@linuxfoundation.org>,
	Tejun Heo <tj@kernel.org>, Balbir Singh <bsingharora@gmail.com>,
	Mike Galbraith <efault@gmx.de>, Oliver Yang <yangoliver@me.com>,
	Shakeel Butt <shakeelb@google.com>, xxx xxx <x.qendo@gmail.com>,
	Taras Kondratiuk <takondra@cisco.com>,
	Daniel Walker <danielwa@cisco.com>,
	Vinayak Menon <vinmenon@codeaurora.org>,
	Ruslan Ruslichenko <rruslich@cisco.com>,
	kernel-team@fb.com
Subject: Re: [PATCH 6/7] psi: pressure stall information for CPU, memory, and IO
Date: Mon, 7 May 2018 17:42:36 -0700	[thread overview]
Message-ID: <024fba07-eece-3878-0924-ea9fd601542d@infradead.org> (raw)
In-Reply-To: <20180507210135.1823-7-hannes@cmpxchg.org>

On 05/07/2018 02:01 PM, Johannes Weiner wrote:
> 
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
> ---
>  Documentation/accounting/psi.txt |  73 ++++++
>  include/linux/psi.h              |  27 ++
>  include/linux/psi_types.h        |  84 ++++++
>  include/linux/sched.h            |  10 +
>  include/linux/sched/stat.h       |  10 +-
>  init/Kconfig                     |  16 ++
>  kernel/fork.c                    |   4 +
>  kernel/sched/Makefile            |   1 +
>  kernel/sched/core.c              |   3 +
>  kernel/sched/psi.c               | 424 +++++++++++++++++++++++++++++++
>  kernel/sched/sched.h             | 166 ++++++------
>  kernel/sched/stats.h             |  91 ++++++-
>  mm/compaction.c                  |   5 +
>  mm/filemap.c                     |  15 +-
>  mm/page_alloc.c                  |  10 +
>  mm/vmscan.c                      |  13 +
>  16 files changed, 859 insertions(+), 93 deletions(-)
>  create mode 100644 Documentation/accounting/psi.txt
>  create mode 100644 include/linux/psi.h
>  create mode 100644 include/linux/psi_types.h
>  create mode 100644 kernel/sched/psi.c
> 
> diff --git a/Documentation/accounting/psi.txt b/Documentation/accounting/psi.txt
> new file mode 100644
> index 000000000000..e051810d5127
> --- /dev/null
> +++ b/Documentation/accounting/psi.txt
> @@ -0,0 +1,73 @@

Looks good to me.


> diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
> new file mode 100644
> index 000000000000..052c529a053b
> --- /dev/null
> +++ b/kernel/sched/psi.c
> @@ -0,0 +1,424 @@
> +/*
> + * Measure workload productivity impact from overcommitting CPU, memory, IO
> + *
> + * Copyright (c) 2017 Facebook, Inc.
> + * Author: Johannes Weiner <hannes@cmpxchg.org>
> + *
> + * Implementation
> + *
> + * Task states -- running, iowait, memstall -- are tracked through the
> + * scheduler and aggregated into a system-wide productivity state. The
> + * ratio between the times spent in productive states and delays tells
> + * us the overall productivity of the workload.
> + *
> + * The ratio is tracked in decaying time averages over 10s, 1m, 5m
> + * windows. Cumluative stall times are tracked and exported as well to

               Cumulative

> + * allow detection of latency spikes and custom time averaging.
> + *
> + * Multiple CPUs
> + *
> + * To avoid cache contention, times are tracked local to the CPUs. To
> + * get a comprehensive view of a system or cgroup, we have to consider
> + * the fact that CPUs could be unevenly loaded or even entirely idle
> + * if the workload doesn't have enough threads. To avoid artifacts
> + * caused by that, when adding up the global pressure ratio, the
> + * CPU-local ratios are weighed according to their non-idle time:
> + *
> + *   Time the CPU had stalled tasks    Time the CPU was non-idle
> + *   ------------------------------ * ---------------------------
> + *                Walltime            Time all CPUs were non-idle
> + */


> +
> +/**
> + * psi_memstall_leave - mark the end of an memory stall section

                                    end of a memory

> + * @flags: flags to handle nested memdelay sections
> + *
> + * Marks the calling task as no longer stalled due to lack of memory.
> + */
> +void psi_memstall_leave(unsigned long *flags)
> +{



-- 
~Randy

  reply	other threads:[~2018-05-08  0:43 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-07 21:01 [PATCH 0/7] " Johannes Weiner
2018-05-07 21:01 ` [PATCH 1/7] mm: workingset: don't drop refault information prematurely Johannes Weiner
2018-05-07 21:01 ` [PATCH 2/7] mm: workingset: tell cache transitions from workingset thrashing Johannes Weiner
2018-05-07 21:01 ` [PATCH 3/7] delayacct: track delays from thrashing cache pages Johannes Weiner
2018-05-07 21:01 ` [PATCH 4/7] sched: loadavg: consolidate LOAD_INT, LOAD_FRAC, CALC_LOAD Johannes Weiner
2018-05-07 21:01 ` [PATCH 5/7] sched: loadavg: make calc_load_n() public Johannes Weiner
2018-05-09  9:49   ` Peter Zijlstra
2018-05-10 13:46     ` Johannes Weiner
2018-05-07 21:01 ` [PATCH 6/7] psi: pressure stall information for CPU, memory, and IO Johannes Weiner
2018-05-08  0:42   ` Randy Dunlap [this message]
2018-05-08 14:06     ` Johannes Weiner
2018-05-08  1:35   ` kbuild test robot
2018-05-08  3:04   ` kbuild test robot
2018-05-08 14:05     ` Johannes Weiner
2018-05-09  9:59   ` Peter Zijlstra
2018-05-10 13:49     ` Johannes Weiner
2018-05-09 10:04   ` Peter Zijlstra
2018-05-10 14:10     ` Johannes Weiner
2018-05-09 10:05   ` Peter Zijlstra
2018-05-10 14:13     ` Johannes Weiner
2018-05-09 10:14   ` Peter Zijlstra
2018-05-10 14:18     ` Johannes Weiner
2018-05-09 10:21   ` Peter Zijlstra
2018-05-10 14:24     ` Johannes Weiner
2018-05-09 10:26   ` Peter Zijlstra
2018-05-09 10:46   ` Peter Zijlstra
2018-05-09 11:38     ` Peter Zijlstra
2018-05-10 13:41       ` Johannes Weiner
2018-05-14  8:33         ` Peter Zijlstra
2018-05-09 10:55   ` Peter Zijlstra
2018-05-09 11:03   ` Vinayak Menon
2018-05-23 13:17     ` Johannes Weiner
2018-05-23 13:19       ` Vinayak Menon
2018-06-07  0:46   ` Suren Baghdasaryan
2018-05-07 21:01 ` [PATCH 7/7] psi: cgroup support Johannes Weiner
2018-05-09 11:07   ` Peter Zijlstra
2018-05-10 14:49     ` Johannes Weiner
2018-05-14 15:39 ` [PATCH 0/7] psi: pressure stall information for CPU, memory, and IO Christopher Lameter
2018-05-14 17:35   ` Bart Van Assche
2018-05-14 18:55   ` Johannes Weiner
2018-05-14 20:15     ` Christopher Lameter
2018-05-26  0:29 ` Suren Baghdasaryan
2018-05-29 18:16   ` Johannes Weiner
2018-05-30 23:32     ` Suren Baghdasaryan

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