Mercurial > hg
comparison hgext/largefiles/overrides.py @ 16120:47ee41fcf42b
largefiles: optimize update speed by only updating changed largefiles
Historically, during 'hg update', every largefile in the working copy was
hashed (which is a very expensive operation on big files) and any
largefiles that did not have a hash that matched their standin were
updated.
This patch optimizes 'hg update' by keeping track of what standins have
changed between the old and new revisions, and only updating the largefiles
that have changed. This saves a lot of time by avoiding the unecessary
calculation of a list of sha1 hashes for big files.
With this patch, the time 'hg update' takes to complete is a function of
how many largefiles need to be updated and what their size is.
Performance tests on a repository with about 80 largefiles ranging from
a few MB to about 97 MB are shown below. The tests show how long it takes
to run 'hg update' with no changes actually being updated.
Mercurial 2.1 release:
$ time hg update
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
getting changed largefiles
0 largefiles updated, 0 removed
real 0m10.045s
user 0m9.367s
sys 0m0.674s
With this patch:
$ time hg update
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
real 0m0.965s
user 0m0.845s
sys 0m0.115s
The same repsoitory, without the largefiles extension enabled:
$ time hg update
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
real 0m0.799s
user 0m0.684s
sys 0m0.111s
So before the patch, 'hg update' with no changes was approximately 9.25s
slower with largefiles enabled. With this patch, it is approximately 0.165s
slower.
author | Na'Tosha Bard <natosha@unity3d.com> |
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date | Mon, 13 Feb 2012 18:37:07 +0100 |
parents | cb756482c1aa |
children | 877aea86fb73 |
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16109:cb756482c1aa | 16120:47ee41fcf42b |
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600 lfdirstate.write() | 600 lfdirstate.write() |
601 finally: | 601 finally: |
602 wlock.release() | 602 wlock.release() |
603 | 603 |
604 def hg_update(orig, repo, node): | 604 def hg_update(orig, repo, node): |
605 # In order to not waste a lot of extra time during the update largefiles | |
606 # step, we keep track of the state of the standins before and after we | |
607 # call the original update function, and only update the standins that | |
608 # have changed in the hg.update() call | |
609 oldstandins = lfutil.getstandinsstate(repo) | |
605 result = orig(repo, node) | 610 result = orig(repo, node) |
606 lfcommands.updatelfiles(repo.ui, repo) | 611 newstandins = lfutil.getstandinsstate(repo) |
612 tobeupdated = set(oldstandins).symmetric_difference(set(newstandins)) | |
613 filelist = [] | |
614 for f in tobeupdated: | |
615 if f[0] not in filelist: | |
616 filelist.append(f[0]) | |
617 | |
618 lfcommands.updatelfiles(repo.ui, repo, filelist=filelist, printmessage=True) | |
607 return result | 619 return result |
608 | 620 |
609 def hg_clean(orig, repo, node, show_stats=True): | 621 def hg_clean(orig, repo, node, show_stats=True): |
610 result = orig(repo, node, show_stats) | 622 result = orig(repo, node, show_stats) |
611 lfcommands.updatelfiles(repo.ui, repo) | 623 lfcommands.updatelfiles(repo.ui, repo) |