What method of profiling do you recommend? I have used gprof previously (it's been awhile) but am not familiar with the subversion project source code and build setup. Is the a online guide or wiki describing the preferred setup for performing this?
Kyle On Sat, Oct 1, 2011 at 3:10 PM, Daniel Shahaf <d...@daniel.shahaf.name>wrote: > Johan Corveleyn wrote on Sat, Oct 01, 2011 at 20:47:29 +0200: > > [ Please do not top-post on this list, i.e. please put your reply > > below or inline. More below ... ] > > > > On Sat, Oct 1, 2011 at 6:49 PM, Kyle Leber <kyle.le...@gmail.com> wrote: > > > On Fri, Sep 30, 2011 at 7:15 PM, Johan Corveleyn <jcor...@gmail.com> > wrote: > > >> > > >> On Fri, Sep 30, 2011 at 3:29 PM, Kyle Leber <kyle.le...@gmail.com> > wrote: > > >> > I've encountered what I think is a problem with subversion, but I'm > not > > >> > completely sure (and according to the online instructions I should > bring > > >> > it > > >> > up here prior to filing a bug). > > >> > > >> Actually, the instructions on > > >> http://subversion.apache.org/issue-tracker.html say that you should > > >> send your report to users@, not dev@. So I'm adding users@. Please > > >> drop dev@ from any further replies. > > >> > > >> > Basically, we're trying to merge a rather large collection of > > >> > fixes back in our trunk. I check out a fresh copy of the trunk, > > >> > then use the merge syntax: svn merge https://path/to/my/branch . > > >> > > > >> > This generally churns along just fine, but we occasionally get > > >> > hung up on medium sized binary files where the svn client jumps > > >> > to 100% cpu usage and sits on it for 3+ hours before moving on to > > >> > the next file. These files are anywhere from 3-10MB in size, so > > >> > not ridiculously huge. We generally have these files marked as > > >> > octet stream, but changing to text did not help the situation > > >> > when we tried that. > > >> > > > >> > I did find an old forum discussion about a potential issue that > > >> > could be related. I was wondering if this was ever addressed and > > >> > could it still be the same problem. Link is here: > > >> > http://www.svnforum.org/threads/36123-Slow-SVN-merge > > >> > > > >> > I'm using svn client 1.6.12. I looked at the online change log > > >> > up through the 1.7 alphas and didn't see any bug fixes that > > >> > sounded relevant. > > >> > > >> This could be a relevant change (listed in the 1.7 release notes, not > > >> in the change log): > > >> > > >> > http://subversion.apache.org/docs/release-notes/1.7.html#diff-optimizations > > >> > > >> Can you please try one of the 1.7 pre-release binaries, and see if it > > >> helps? See http://subversion.apache.org/packages.html#pre-release > > >> > > > Thanks, Johan. I tested with 1.7rc4 and it did not make any > perceptible > > > difference. Anything else I can try? > > > > Hm, that's unfortunate. > > > > Actually, it was to be expected that this wouldn't help, because the > > diff-optimizations in 1.7 only play a role when merging text files > > (and diffing and blaming). And you said those > > "files-that-make-merge-hang" are generally marked as octet-stream, and > > changing them to text made no difference. > > > > That seems to indicate that the 100% cpu usage on the client isn't > > spent in the diff code (unlike the forum thread that you linked to, > > where the poster tracked it down to libsvn_diff/lcs.c --- he would > > definitely have been helped by the 1.7 improvements). > > > > What does 'svn merge' do for binary files? I checked svn_wc__merge() > a few months ago and for binary files all it knew to do was > > (a) if mine == merge-left then set merged := merge-right > (b) invoke the configured diff3-cmd > (c) raise a conflict > > but it didn't do any line-based merge (per Johan's second response). > > > So there's another reason. Maybe it has something to do with (lots of) > > subtree mergeinfo? Can you verify if there is a lot of svn:mergeinfo > > on directories and files all over the place? > > > > Also: can you tell us what version is running on the server? > > > > Maybe other people on this list have had similar experiences, and can > > give some suggestions? > > > > Another line of thought: the algorithm for computing binary deltas > changed a few years ago, and I recall reading (on old bug reports?) > about some cases in which the delta combiner would be inefficient for > deltas generated by old servers --- i.e., it would be expensive to 'svn > cat' files that were committed to old servers in repositories that > haven't been dumped/loaded by a newer server. > > In any case: can you run the merge under a profiler and tell us in what > function(s) time is spent? > > Daniel > > > -- > > Johan >
