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From: Olof Johansson <olof@lixom.net>
To: Mike Galbraith <efault@gmx.de>
Cc: Willy Tarreau <w@1wt.eu>,
	linux-kernel@vger.kernel.org,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Ingo Molnar <mingo@elte.hu>
Subject: Re: Scheduler(?) regression from 2.6.22 to 2.6.24 for short-lived threads
Date: Mon, 11 Feb 2008 11:26:48 -0600	[thread overview]
Message-ID: <20080211172648.GA7962@lixom.net> (raw)
In-Reply-To: <1202717755.21339.65.camel@homer.simson.net>

On Mon, Feb 11, 2008 at 09:15:55AM +0100, Mike Galbraith wrote:
> Piddling around with your testcase, it still looks to me like things
> improved considerably in latest greatest git.  Hopefully that means
> happiness is in the pipe for the real workload... synthetic load is
> definitely happier here as burst is shortened.

The real workload doesn't see much of an improvement. The changes I did
when tinkering yesterday seem like they're better at modelling just
what's going on with that one.

I've added the new testcase I'm using for the numbers I posted last
night at http://lixom.net/~olof/threadtest/new/, including numbers for
the various kernels. I also included the binaries I built. (with "gcc
-DLOOPS=<size> testcase.c -lpthread").

I tried graphing the numbers as well, it looks like for larger workloads
that 2.6.22 has a fixed benefit over newer kernels. I.e. it seems quicker
at rebalancing, but once things balance out they're obviously doing ok
independent of kernel version.

Graph at http://lixom.net/olof/threadtest/new/schedgraph.pdf. I couldn't
figure out how to make the X axis linear, so it obviously looks odd with
the current powers-of-two at the end instead of linear, but the
differences can still be seen clearly.


-Olof


  reply	other threads:[~2008-02-11 17:25 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-09  0:04 Olof Johansson
2008-02-09  0:08 ` Ingo Molnar
2008-02-09  0:32   ` Olof Johansson
2008-02-09  7:58 ` Mike Galbraith
2008-02-09  8:03   ` Willy Tarreau
2008-02-09 10:58     ` Mike Galbraith
2008-02-09 11:40       ` Willy Tarreau
2008-02-09 13:37         ` Mike Galbraith
2008-02-09 16:19           ` Willy Tarreau
2008-02-09 17:33             ` Mike Galbraith
2008-02-10  5:29             ` Olof Johansson
2008-02-10  6:15               ` Willy Tarreau
2008-02-10  7:00                 ` Olof Johansson
2008-02-10  7:58                   ` Willy Tarreau
2008-02-11  8:15                   ` Mike Galbraith
2008-02-11 17:26                     ` Olof Johansson [this message]
2008-02-11 19:58                       ` Mike Galbraith
2008-02-11 20:31                         ` Olof Johansson
2008-02-12  9:23                           ` Mike Galbraith
2008-02-13  5:49                             ` Mike Galbraith
2008-02-11 21:45               ` Bill Davidsen
2008-02-12  4:30                 ` Mike Galbraith
     [not found] <fa.6N2dhyJ1cmBqiuFKgCaYfwduM+0@ifi.uio.no>
2008-02-09  1:49 ` Robert Hancock

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