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Re: PATCH: first pass of wrapup_global_declarations performanceimprovements
- From: Mark Mitchell <mark at codesourcery dot com>
- To: Matt Austern <austern at apple dot com>, "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Date: Tue, 18 Feb 2003 08:25:37 -0800
- Subject: Re: PATCH: first pass of wrapup_global_declarations performanceimprovements
--On Friday, February 14, 2003 01:08:22 PM -0800 Matt Austern
This is OK, thanks.
This patch does two things.
First, it changes an unconditional write into a conditional write. This
is because, empirically, the unconditional write dirties pages
unnecessarily. This is a noticeable performance problem, especially when
You should probably also add a note to the coding standards page (wherever
that is; I've forgotten) to advocate using a conditional in situations like
that, if we really think that's likely to be a win in many places. Or else
a comment in this one, indicating that.
(It occurs to me that this is actually a job for profile-directed feedback;
if I'm setting these bits to the same value they already have 99% of the
time, it's probably a good idea to insert an additional read, and leave out
Mark Mitchell firstname.lastname@example.org
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