Re: [Monotone-devel] fast compiles!

[Nathaniel Smith]

On Mon, Apr 26, 2004 at 10:18:42PM -0600, Derek Scherger wrote:
> I seem to remember reading something somewhere about monotone's compile 
> times being an issue and from what I've seen I would definitely agree. A 
> trivial change to commands.cc takes close to a minute to compile on my dual 
> Athlon 2000 which has 3GB of RAM to work with.
> 
> I've just installed Andrew Tridgell's ccache package 
> (http://ccache.samba.org/) and it makes a *huge* difference.
[...]
> That's something like an 18x speedup.

ccache is indeed awesome.  These numbers, though, are unfortunately
meaningless.  What you're seeing here is that ccache is smart enough
to realize the 'touch' hasn't actually changed the file, and so it
doesn't recompile it at all.  But unless you go around all day
'touch'ing your files, that isn't a useful number; most developers
actually change the files, and in that case ccache has to recompile
them anyway.  (It does help if your modifications are to comments or
#defines that don't effect a particular file or whatever, though.)

For a much more general speedup, now that gcc 3.4.0 is out someone
could look into getting the monotone build system to support
precompiled headers...

-- Nathaniel

-- 
The Universe may  /  Be as large as they say
But it wouldn't be missed  /  If it didn't exist.
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