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Re: [PATCH] normal_distribution<double> performance improvement with SSE

From: Paolo Carlini <paolo dot carlini at oracle dot com>
To: Ulrich Drepper <drepper at gmail dot com>
Cc: libstdc++ at gcc dot gnu dot org, GCC Patches <gcc-patches at gcc dot gnu dot org>
Date: Wed, 26 Sep 2012 13:24:45 +0200
Subject: Re: [PATCH] normal_distribution<double> performance improvement with SSE
References: <CAOPLpQcrVcVN0yZtgY9P+m_YA8E3Efdh9QzG17dGyJ2-Tg2o3Q@mail.gmail.com>

Hi,

On 09/26/2012 01:16 PM, Ulrich Drepper wrote:

Here is a patch to accelerate the __generate function for the
normal_distribution<double> class.  The speed-up is quite significant,
the amount depending on which random number engine is used.

mt19937 +20%

mt19937_64 +30%

sfmt19937 +30%

sfmt19937_64 +30%


This patch introduces a header with optimizations for <random>.  No
changes to existing code needed, this is a straight-forward
specialization.  Tested on x86_64-linux.  More optimizations follow,
there is still quite a bit of inefficiency in the existing interfaces.
  OK to commit?

Looks fine to me. I suppose you want _Power_of_2 inline?

Paolo.

References:
- [PATCH] normal_distribution<double> performance improvement with SSE
  - From: Ulrich Drepper

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