From: Frederic Weisbecker <fweisbec@gmail.com>
To: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
hpa@zytor.com, rostedt@goodmis.org, akpm@linux-foundation.org,
tglx@linutronix.de,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC 4/4] cputime: remove scaling
Date: Thu, 11 Apr 2013 17:06:39 +0200 [thread overview]
Message-ID: <20130411150637.GB15699@somewhere> (raw)
In-Reply-To: <20130411083634.GB1380@redhat.com>
On Thu, Apr 11, 2013 at 10:36:35AM +0200, Stanislaw Gruszka wrote:
> > I really prefer robust kernel side accounting/instrumentation.
>
> We have CONFIG_IRQ_TIME_ACCOUNTING and CONFIG_VIRT_CPU_ACCOUNTING_GEN.
> Perhaps we can change to use one of those options by default. I wonder
> if the additional performance cost related with them is really something
> that we should care about. Are there any measurement that show those
> will make performance worse ?
CONFIG_IRQ_TIME_ACCOUNTING also make use of scaling. And CONFIG_VIRT_CPU_ACCOUNTING_GEN
involves too much overhead on IO-bound workloads. It's mostly good for
undisturbed userspace bound workloads (few IRQs, few exceptions, few syscalls).
prev parent reply other threads:[~2013-04-11 15:06 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-28 16:53 [RFC 0/4] do not make cputime scaling in kernel Stanislaw Gruszka
2013-03-28 16:53 ` [RFC 1/4] cputime: change parameter of thread_group_cputime_adjusted Stanislaw Gruszka
2013-03-28 16:53 ` [RFC 2/4] procfs: add sum_exec_runtime to /proc/PID/stat Stanislaw Gruszka
2013-03-28 16:53 ` [RFC 3/4] sched,proc: add csum_sched_runtime Stanislaw Gruszka
2013-03-28 16:53 ` [RFC 4/4] cputime: remove scaling Stanislaw Gruszka
2013-04-10 12:02 ` Ingo Molnar
2013-04-10 14:29 ` H. Peter Anvin
2013-04-11 8:37 ` Stanislaw Gruszka
2013-04-11 15:19 ` H. Peter Anvin
2013-04-11 8:36 ` Stanislaw Gruszka
2013-04-11 15:06 ` Frederic Weisbecker [this message]
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