Re: Better value for chunk_size when threaded

[Nicolas Pitre <nico@cam.org>]

On Mon, 10 Dec 2007, Andreas Ericsson wrote:

> Nicolas Pitre wrote:
> > If there is one besides futzing with /proc/cpuinfo I'd like to know about
> > it.  Bonus points if it is portable.
> > 
> 
> Here is such a one. I've sent it before, using git-send-email, but that
> one doesn't seem to work too well for all list-members, probably because
> my own laptop appears to be the original SMTP-server and its name can't
> be looked up. Sorry for inlining it here instead of sending it as a mail
> on its own, but I have absolutely no idea how to get git-send-email to
> do ldap authentication and connect to our tls-enabled smtp-server
> without using /usr/bin/sendmail and adding my laptop as originating
> smtp-server.
> 
> This patch replaces the one I sent earlier and *should* work on
> everything from Irix and AIX to Linux, Windows and every other
> posixish system. It passes all tests, both with and without
> THREADED_DELTA_SEARCH, and causes our weekly repack of our
> mother-ship repos to run roughly 4 times as fast (4 cores, no
> previous thread config).
> 
> Extract with
>   sed -n -e /^##SEDMEHERE##/,/##TOHERE##/p -e /^##/d
> 
> ##SEDMEHERE##
> > From ddf08303bd7962be385abbd5e964455a90ed6055 Mon Sep 17 00:00:00 2001
> From: Andreas Ericsson <ae@op5.se>
> Date: Thu, 6 Dec 2007 22:09:27 +0100
> Subject: [PATCH] pack-objects: Add runtime detection of number of CPU's
> 
> Packing objects can be done in parallell nowadays, but
> it's only done if the config option pack.threads is set
> to a value above 1. Because of that, the code-path used
> is sometimes not the most optimal one.
> 
> This patch adds a routine to detect the number of active
> CPU's at runtime, which should provide a better default
> and activate the (hopefully) better codepath more often.

Your patch is whitespace dammaged.

Also please make it into a separate .c file.  One day, maybe index-pack 
will want to use it as well.


Nicolas