Messages in this thread | | | From | Pengfei Yuan <> | Date | Tue, 7 Apr 2015 11:37:27 +0800 | Subject | Why not build kernel with -O3 |
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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
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