From: William Lee Irwin III <wli@holomorphy.com>
To: Pavel Machek <pavel@ucw.cz>
Cc: Con Kolivas <kernel@kolivas.org>,
linux kernel mailing list <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@osdl.org>, Ingo Molnar <mingo@elte.hu>,
Peter Williams <pwil3058@bigpond.net.au>,
Alexander Nyberg <alexn@dsv.su.se>,
Nick Piggin <nickpiggin@yahoo.com.au>
Subject: Re: [PATCH][plugsched 0/28] Pluggable cpu scheduler framework
Date: Sun, 31 Oct 2004 17:42:30 -0800 [thread overview]
Message-ID: <20041101014230.GC2583@holomorphy.com> (raw)
In-Reply-To: <20041031233313.GB6909@elf.ucw.cz>
At some point in the past, Con Kolivas wrote:
>> This code was designed to touch the least number of files, be completely
>> arch-independant, and allow extra schedulers to be coded in by only
>> touching Kconfig, scheduler.c and scheduler.h. It should incur no
>> overhead when run and will allow you to compile in only the scheduler(s)
>> you desire. This allows, for example, embedded hardware to have a tiny
>> new scheduler that takes up minimal code space.
On Mon, Nov 01, 2004 at 12:33:13AM +0100, Pavel Machek wrote:
> You are changing
> some_functions()
> into
> something->function()
> no? I do not think that is 0 overhead...
It's nonzero, yes. However, it's rather small with modern branch
predictors; older microarchitectures handled this less well, which
is probably why you expect a measurable hit. It may still have
non-negligible performance effects on some legacy architectures,
but I would not let that hold up progress.
-- wli
next prev parent reply other threads:[~2004-11-01 1:44 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-10-30 14:32 [PATCH][plugsched 0/28] Pluggable cpu scheduler framework Con Kolivas
2004-10-31 23:33 ` Pavel Machek
2004-10-31 23:37 ` Con Kolivas
2004-11-01 1:42 ` William Lee Irwin III [this message]
2004-11-01 11:41 ` Ingo Molnar
2004-11-01 13:08 ` Kasper Sandberg
2004-11-01 13:32 ` Con Kolivas
2004-11-01 14:23 ` Nick Piggin
2004-11-01 17:54 ` Jesse Barnes
2004-11-02 21:28 ` Matthias Urlichs
2004-11-02 22:30 ` Peter Chubb
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