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.
What is the size difference with -O3?
Do you have mostly-userspace benchmark? (kernel build?) -O3 could hurt there
if it produces bigger code..
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
--
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/
