From: Christopher Lameter <cl@linux.com>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-block@vger.kernel.org, cgroups@vger.kernel.org,
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 0/7] psi: pressure stall information for CPU, memory, and IO
Date: Mon, 14 May 2018 15:39:33 +0000 [thread overview]
Message-ID: <010001635f4e8be9-94e7be7a-e75c-438c-bffb-5b56301c4c55-000000@email.amazonses.com> (raw)
In-Reply-To: <20180507210135.1823-1-hannes@cmpxchg.org>
On Mon, 7 May 2018, Johannes Weiner wrote:
> What to make of this number? If CPU utilization is at 100% and CPU
> pressure is 0, it means the system is perfectly utilized, with one
> runnable thread per CPU and nobody waiting. At two or more runnable
> tasks per CPU, the system is 100% overcommitted and the pressure
> average will indicate as much. From a utilization perspective this is
> a great state of course: no CPU cycles are being wasted, even when 50%
> of the threads were to go idle (and most workloads do vary). From the
> perspective of the individual job it's not great, however, and they
> might do better with more resources. Depending on what your priority
> is, an elevated "some" number may or may not require action.
This looks awfully similar to loadavg. Problem is that loadavg gets
screwed up by tasks blocked waiting for I/O. Isnt there some way to fix
loadavg instead?
next prev parent reply other threads:[~2018-05-14 15:39 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-07 21:01 [PATCH 0/7] psi: pressure stall information for CPU, memory, and IO 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
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 ` Christopher Lameter [this message]
2018-05-14 17:35 ` [PATCH 0/7] psi: pressure stall information for CPU, memory, and IO 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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