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Re: 1.7.x - merge now accesses all files in WC?

From: Daniel Becroft <djcbecroft_at_gmail.com>
Date: Mon, 6 Dec 2010 18:32:09 +1000

On Mon, Dec 6, 2010 at 8:09 AM, Stefan Sperling <stsp_at_elego.de> wrote:

> On Mon, Dec 06, 2010 at 07:18:56AM +1000, Daniel Becroft wrote:
> > On Fri, Dec 3, 2010 at 9:22 AM, Peter Samuelson <peter_at_p12n.org> wrote:
> >
> > >
> > > [Daniel Becroft]
> > > > I've just managed to build/install trunk on my ubuntu box at home
> (first
> > > > application I've ever compiled on it - yey!).
> > > >
> > > > What debugging tools would you recommend to investigate this further?
> > > I've
> > > > seen output posted that lists function names, and time spent on each.
> > >
> > > The obvious start is 'strace', as in 'strace svn merge ...'. It spits
> > > out every system call. There's a lot of noise up front as it's loading
> > > shared libraries and such, but it should still be obvious what we're
> > > doing when crawling the tree (stat / lstat, open, etc.).<
> http://p12n.org/>
> >
> >
> > Thanks. I've run that, and all the calls are lstat(). There are 16 for
> each
> > file (or at least, those not affected by the merge). I've copied on of
> the
> > calls below (all 16 of these are identical).
> >
> > lstat("....../dev/workingcopy/A/beta.txt", {st_dev=makedev(8, 1),
> > st_ino=23855167, st_mode=S_IFREG|0644, st_nlink=1, st_uid=1000,
> st_gid=1000,
> > st_blksize=4096, st_blocks=8, st_size=5, st_atime=2010/12/06-07:10:42,
> > st_mtime=2010/12/06-07:10:42, st_ctime=2010/12/06-07:10:42}) = 0
> >
> > It does appear that it's a known issue though. I'll keep investigating to
> > try and understand why it's getting called at all. Thanks for your help.
>
> That's probably the svn_wc_revision_status2() call in
> ensure_wc_is_suitable_merge_target() (subversion/libsvn_client/merge.c).
>
> 1.6.x should be doing the same during reintegrate merges.
> 1.7 does it for every merge.
>
> To verify my theory you can try the patch below.
> We could try to optimize this if it is a problem.
>
> Stefan
>
> Index: subversion/libsvn_client/merge.c
> ===================================================================
> --- subversion/libsvn_client/merge.c (revision 1042308)
> +++ subversion/libsvn_client/merge.c (working copy)
> @@ -9022,6 +9022,7 @@ ensure_wc_is_suitable_merge_target(const char *tar
> svn_boolean_t allow_switched_subtrees,
> apr_pool_t *scratch_pool)
> {
> +#if 0
> svn_wc_revision_status_t *wc_stat;
>
> /* Avoid the following status crawl if we don't need it. */
> @@ -9068,6 +9069,7 @@ ensure_wc_is_suitable_merge_target(const char *tar
> wc_stat->min_rev, wc_stat->max_rev);
> }
>
> +#endif
> return SVN_NO_ERROR;
> }
>

Hey Stefan,

I've applied the patch, and re-run the test. It's cut the calls down from 16
to 10.

Cheers,
Daniel B.
Received on 2010-12-06 09:33:06 CET

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