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From: Pengfei Yuan <0xcoolypf@gmail.com>
To: linux-kernel@vger.kernel.org
Subject: Why not build kernel with -O3
Date: Tue, 7 Apr 2015 11:37:27 +0800	[thread overview]
Message-ID: <CACmZjJK8oLLFWBzUZpRTVrTycu8JDfd+hg6bBuxi-a8U6Hk_1A@mail.gmail.com> (raw)

Hi,

I have conducted some experiments to compare kernels built with -O2
and -O3. Here are the results:

Application  Performance O2   Performance O3   Improvement
Apache       127814.14 req/s  130321.24 req/s  1.96%
Nginx        537589.08 req/s  556723.32 req/s  3.56%
MySQL        70661.38 tx/s    71008.47 tx/s    0.49%
PostgreSQL   79763.39 tx/s    79535.59 tx/s    -0.29%
Redis        352547.47 op/s   405417.24 op/s   15.0%
Memcached    844439.14 op/s   845321.79 op/s   0.10%

Geomean: +3.34%

Experiment environment: Linux 3.19.3, GCC 4.9.3 prerelease, Core-i7
4770, 32G RAM, 10GbE

LMbench microbenchmark also shows reduction in various latencies, as
well as increase of throughputs.

Why not add an option to build kernel with -O3?

Regards,
YUAN, Pengfei

             reply	other threads:[~2015-04-07  3:37 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-07  3:37 Pengfei Yuan [this message]
2015-04-07  6:43 ` Why not build kernel with -O3 Mike Galbraith
2015-04-07  7:07   ` Boaz Harrosh
2015-04-07  8:29     ` Mike Galbraith
2015-04-07  7:56   ` Pengfei Yuan
2015-04-07 10:09     ` Mike Galbraith
2015-04-07 18:05       ` Austin S Hemmelgarn
2015-04-08  1:00         ` Pengfei Yuan
2015-04-08 12:06           ` Austin S Hemmelgarn
2015-04-08 12:57             ` One Thousand Gnomes
2015-04-08 13:19             ` Pengfei Yuan
2015-04-08 13:53               ` Austin S Hemmelgarn
2015-04-08 12:19           ` Richard Weinberger
2015-04-08 12:49             ` Austin S Hemmelgarn
2015-04-08 13:16             ` Pengfei Yuan
2015-04-08 13:21               ` Richard Weinberger
2015-04-27 20:37 ` Pavel Machek

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