[prev in list] [next in list] [prev in thread] [next in thread] 

List:       gentoo-user
Subject:    Re: [gentoo-user] ccache results [was; checking for.....
From:       Uwe Thiem <uwix () iway ! na>
Date:       2008-05-03 17:23:31
Message-ID: 200805031823.32294.uwix () iway ! na
[Download RAW message or body]

On Saturday 03 May 2008, David Relson wrote:
> On Sat, 3 May 2008 14:17:39 +0100
>
> Uwe Thiem wrote:
> > On Saturday 03 May 2008, David Relson wrote:
> > > On Fri, 2 May 2008 07:10:02 -0400
> > > David Relson wrote:
> > >
> > > ...[snip]...
> > >
> > > > As part of identifying the capabilities and files of your
> > > > operating system (distro) ./configure creates a lot of small
> > > > programs and compiles them.  I can see how caching
> > > > compilation info would help with this.
> > >
> > > I ran a quick test with ccache and ./configure.  Using
> > > bogofilter's configure script (because it was available):
> > >
> > > before installing ccache:
> > >
> > >   3 runs of ./configure averaged 6.07s
> > >
> > > ... installed ccache ...
> > >
> > >   next run took 6.5 sec (slower than before)
> > >   next 3 runs averaged 4.96s (18.4% better than before)
> >
> > All your configure runs were for the same package, right?
>
> Correct.
>
> > > conclusion:  ccache _does_ help ./configure
> >
> > It does not for different packages, AFAIK. And that was the
> > question of the OP.
>
> There _should_ be some effect as there are many operations common
> amongst configure scripts, for example determining the name of
> the header file defining malloc or determining whether to use bzero
> or memset, etc, etc.  As with any form of caching the rate of cache
> hits will vary depending on load and cache size.
> k

Disclaimer: I haven't tried this out. It's all speculation. ;-)

There might be a way. If you don't set "ccache" as FEATURE 
in /etc/make.conf but mv /usr/bin/ccache to /usr/local/bin/ccache. 
Then make the following symlinks:
ln -s /usr/local/bin/ccache /usr/local/bin/gcc
ln -s /usr/local/bin/ccache /usr/local/bin/g++
ln -s /usr/local/bin/ccache /usr/local/bin/cc

Next step: Make sure that /usr/local/bin comes before /usr/bin in your 
PATH.

With this setup, every identical test program generated and compiled 
by configure may seem to be identical for ccache. As I have said, 
haven't tried it.

Anyway, it seems to me that more and more projects switch from 
autotools to cmake which is *much* faster than autotools.

Uwe

-- 
Ignorance killed the cat, sir, curiosity was framed!
-- 
gentoo-user@lists.gentoo.org mailing list

[prev in list] [next in list] [prev in thread] [next in thread]