[PATCH][libstdc++-v3 parallel mode] Speed up random_shuffle

Paolo Carlini paolo.carlini@oracle.com
Tue Mar 30 13:28:00 GMT 2010


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.



More information about the Gcc-patches mailing list