[Gnu-arch-users] Re: [PATCH] arch speedups on big trees

[Chris Mason]

On Wed, 2004-01-07 at 21:28, Miles Bader wrote:
> Chris Mason <address@hidden> writes:
> > > That part is actually easy.  arch_make_changeset creates the tmpfile,
> > > but could instead push that responsibility to arch_invoke_diff.  It
> > > would only be created/unlinked if the diff func reported changes.
> > 
> > Once the suse internal mirror gets going, you can grab
> > ftp.suse.com/pub/people/mason/patches/arch/arch-faster-7.diff.gz
> 
> This doesn't apply to the default sources -- which seems to call
> arch_invoke_diff on every file in the tree anyway.
> 
The incremental?  No, it doesn't apply.  But the changes to
arch_make_changeset in arch-faster-7.diff are pretty obvious if you want
to pull them out.

> Actually, it also won't fix the case I mentioned.  Basically I'd like to
> see the temporary output file avoided _even when diff is invoked_ (which
> is all too often with the current tla); obvious invoking diff and
> reading the files unnecessarily is a lose, but the number of NFS rpcs
> could maybe be halved by not using an output tmp file, and
> directory-modifying and creation operations seems unusually pokey.
> 

Because of arch_binary_files_differ(), diff is only going to get run
when the files are really different.  Using a pipe probably won't work,
since we'd need some way to deal with the case where diff is blocking
because the pipe is full.  It would be best to just make a file in
TMPDIR instead.

-chris