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Date: Thu, 30 Jun 2005 18:55:57 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Kristian Benoit <kbenoit@opersys.com>
Cc: linux-kernel@vger.kernel.org, paulmck@us.ibm.com, bhuey@lnxw.com,
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Subject: Re: PREEMPT_RT and I-PIPE: the numbers, take 3
Message-ID: <20050630165557.GA15692@elte.hu>
References: <42C320C4.9000302@opersys.com>
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* Kristian Benoit <kbenoit@opersys.com> wrote:

> "plain" run:
> 
> Measurements   |   Vanilla   |  preemp_rt     |
> ---------------+-------------+----------------+
> fork           |      93us   |  157us (+69%)  |
> open/close     |     2.3us   |  3.7us (+43%)  |
> execve         |     351us   |  446us (+27%)  |
> select 500fd   |    12.7us   | 25.8us (+103%) |
> mmap           |     660us   | 2867us (+334%) |
> pipe           |     7.1us   | 11.6us (+63%)  |

update: these tests should perform significantly better on the freshly 
released -50-37 (or later) PREEMPT_RT kernels. (fork, execve, mmap [*] 
was improved in -50-36, the others in -50-37)

	Ingo

[*] the extent of the above fork/execve/mmap costs is still unexplained, 
    unless the test was run with HIGHMEM64 and HIGHPTE enabled.