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Re: [PATCH][libstdc++-v3 parallel mode] Speed up random_shuffle
- From: Paolo Carlini <paolo dot carlini at oracle dot com>
- To: Johannes Singler <singler at kit dot edu>
- Cc: libstdc++ <libstdc++ at gcc dot gnu dot org>, gcc-patches at gcc dot gnu dot org
- Date: Tue, 30 Mar 2010 15:27:39 +0200
- Subject: Re: [PATCH][libstdc++-v3 parallel mode] Speed up random_shuffle
- References: <4BB1EBDC.5080204@kit.edu>
On 03/30/2010 02:17 PM, Johannes Singler wrote:
> This patch speeds up parallel random_shuffle for 1 thread
> forced-parallel execution, and for small inputs in general.
>
> timings before
> 10000 0.000635 0.000648 0.000645 0.000647 0.000647
> 0.000646 0.000646 0.000646 0.000647
> 1000000 0.086243 0.082482 0.030204 0.021635 0.015495
> 0.014524 0.017958 0.010846 0.008236
>
> timings after
> 10000 0.000635 *0.000395* *0.000300* *0.000283*
> *0.000170* *0.000168* *0.000167* *0.000166* *0.000121*
> 1000000 0.086378 *0.056726* 0.029879 0.021753 0.015436
> 0.014460 0.017390 0.010898 0.008257
>
Excellent.
> Tested x86_64-unknown-linux-gnu: No new regressions
>
> Please approve for mainline. gcc-4_4-branch also?
>
I'd rather leave 4_4-branch alone, at this point. Ok for mainline.
Thanks.
Paolo.