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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
