From: David Miller <davem@davemloft.net>
To: pabeni@redhat.com
Cc: torvalds@linux-foundation.org, frederic@kernel.org,
linux-kernel@vger.kernel.org, alexander.levin@verizon.com,
peterz@infradead.org, mchehab@s-opensource.com,
hannes@stressinduktion.org, paulmck@linux.vnet.ibm.com,
wanpeng.li@hotmail.com, dima@arista.com, tglx@linutronix.de,
akpm@linux-foundation.org, rrendec@arista.com, mingo@kernel.org,
sgruszka@redhat.com, riel@redhat.com, edumazet@google.com,
nks.gnu@gmail.com
Subject: Re: [RFC PATCH 0/4] softirq: Per vector threading v3
Date: Wed, 24 Jan 2018 10:05:58 -0500 (EST) [thread overview]
Message-ID: <20180124.100558.97132829347179555.davem@davemloft.net> (raw)
In-Reply-To: <1516805645.2476.23.camel@redhat.com>
From: Paolo Abeni <pabeni@redhat.com>
Date: Wed, 24 Jan 2018 15:54:05 +0100
> Niklas suggested a possible relation with CONFIG_IRQ_TIME_ACCOUNTING=y
> and indeed he was right.
>
> The patched kernel under test had CONFIG_IRQ_TIME_ACCOUNTING set, and
> very little CPU time was accounted to the kworker:
>
> [2125 is the relevant kworker's pid]
> grep sum_exec_runtime /proc/2125/sched; sleep 10; grep sum_exec_runtime /proc/2125/sched
> se.sum_exec_runtime : 13408.239286
> se.sum_exec_runtime : 13456.907197
>
> despite such process was processing a lot of packets and basically
> burning a CPU.
So IRQ_TIME_ACCOUNTING makes the scheduler think that the worker
threads are using nearly no task time at all.
The existing ksoftirqd code should hit the same problem, right?
next prev parent reply other threads:[~2018-01-24 15:06 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-19 15:46 [RFC PATCH 0/4] softirq: Per vector threading v3 Frederic Weisbecker
2018-01-19 15:46 ` [RFC PATCH 1/4] softirq: Limit vector to a single iteration on IRQ tail Frederic Weisbecker
2018-01-19 16:16 ` David Miller
2018-01-19 18:25 ` Linus Torvalds
2018-01-19 18:47 ` David Miller
2018-01-21 16:30 ` Frederic Weisbecker
2018-01-21 16:57 ` David Miller
2018-01-19 15:46 ` [RFC PATCH 2/4] softirq: Per vector deferment to workqueue Frederic Weisbecker
2018-01-20 8:41 ` Pavan Kondeti
2018-01-21 16:11 ` Frederic Weisbecker
2018-01-21 17:50 ` Pavan Kondeti
2018-01-21 20:48 ` Frederic Weisbecker
2018-02-08 17:44 ` Sebastian Andrzej Siewior
2018-02-08 18:45 ` David Miller
2018-02-08 20:14 ` Dmitry Safonov
2018-02-08 20:22 ` David Miller
2018-02-08 20:30 ` Dmitry Safonov
2018-02-09 4:11 ` Mike Galbraith
2018-02-09 12:35 ` Sebastian Andrzej Siewior
2018-02-15 16:13 ` Frederic Weisbecker
2018-02-15 16:58 ` Sebastian Andrzej Siewior
2018-01-19 15:46 ` [RFC PATCH 3/4] softirq: Defer to workqueue when rescheduling is needed Frederic Weisbecker
2018-01-19 15:46 ` [RFC PATCH 4/4] softirq: Replace ksoftirqd with workqueues entirely Frederic Weisbecker
2018-01-22 19:58 ` [RFC PATCH 0/4] softirq: Per vector threading v3 Mauro Carvalho Chehab
2018-01-23 10:13 ` Paolo Abeni
2018-01-23 12:32 ` Dmitry Safonov
2018-01-24 2:12 ` Frederic Weisbecker
2018-01-23 16:22 ` David Miller
2018-01-23 16:57 ` Paolo Abeni
2018-01-23 17:42 ` Linus Torvalds
2018-01-23 18:01 ` Mike Galbraith
2018-01-23 18:24 ` David Miller
2018-01-24 1:57 ` Frederic Weisbecker
2018-01-24 2:01 ` Frederic Weisbecker
2018-01-24 14:54 ` Paolo Abeni
2018-01-24 15:05 ` David Miller [this message]
2018-01-24 16:11 ` Paolo Abeni
2018-02-07 14:18 ` Mauro Carvalho Chehab
2018-03-01 15:21 ` Frederic Weisbecker
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