Mercurial > hg
view tests/test-convert-svn-encoding.t @ 38732:be4984261611
merge: mark file gets as not thread safe (issue5933)
In default installs, this has the effect of disabling the thread-based
worker on Windows when manifesting files in the working directory. My
measurements have shown that with revlog-based repositories, Mercurial
spends a lot of CPU time in revlog code resolving file data. This ends
up incurring a lot of context switching across threads and slows down
`hg update` operations when going from an empty working directory to
the tip of the repo.
On mozilla-unified (246,351 files) on an i7-6700K (4+4 CPUs):
before: 487s wall
after: 360s wall (equivalent to worker.enabled=false)
cpus=2: 379s wall
Even with only 2 threads, the thread pool is still slower.
The introduction of the thread-based worker (02b36e860e0b) states that
it resulted in a "~50%" speedup for `hg sparse --enable-profile` and
`hg sparse --disable-profile`. This disagrees with my measurement
above. I theorize a few reasons for this:
1) Removal of files from the working directory is I/O - not CPU - bound
and should benefit from a thread pool (unless I/O is insanely fast
and the GIL release is near instantaneous). So tests like `hg sparse
--enable-profile` may exercise deletion throughput and aren't good
benchmarks for worker tasks that are CPU heavy.
2) The patch was authored by someone at Facebook. The results were
likely measured against a repository using remotefilelog. And I
believe that revision retrieval during working directory updates with
remotefilelog will often use a remote store, thus being I/O and not
CPU bound. This probably resulted in an overstated performance gain.
Since there appears to be a need to enable the thread-based worker with
some stores, I've made the flagging of file gets as thread safe
configurable. I've made it experimental because I don't want to formalize
a boolean flag for this option and because this attribute is best
captured against the store implementation. But we don't have a proper
store API for this yet. I'd rather cross this bridge later.
It is possible there are revlog-based repositories that do benefit from
a thread-based worker. I didn't do very comprehensive testing. If there
are, we may want to devise a more proper algorithm for whether to use
the thread-based worker, including possibly config options to limit the
number of threads to use. But until I see evidence that justifies
complexity, simplicity wins.
Differential Revision: https://phab.mercurial-scm.org/D3963
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Wed, 18 Jul 2018 09:49:34 -0700 |
parents | d624c8558c61 |
children | a915db9a5e77 |
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#require svn svn-bindings $ cat >> $HGRCPATH <<EOF > [extensions] > convert = > EOF $ svnadmin create svn-repo $ svnadmin load -q svn-repo < "$TESTDIR/svn/encoding.svndump" Convert while testing all possible outputs $ hg --debug convert svn-repo A-hg --config progress.debug=1 initializing destination A-hg repository reparent to file:/*/$TESTTMP/svn-repo (glob) run hg sink pre-conversion action scanning source... found trunk at 'trunk' found tags at 'tags' found branches at 'branches' found branch branch\xc3\xa9 at 5 (esc) found branch branch\xc3\xa9e at 6 (esc) scanning: 1/4 revisions (25.00%) reparent to file:/*/$TESTTMP/svn-repo/trunk (glob) fetching revision log for "/trunk" from 4 to 0 parsing revision 4 (2 changes) parsing revision 3 (4 changes) parsing revision 2 (3 changes) parsing revision 1 (3 changes) no copyfrom path, don't know what to do. '/branches' is not under '/trunk', ignoring '/tags' is not under '/trunk', ignoring scanning: 2/4 revisions (50.00%) reparent to file:/*/$TESTTMP/svn-repo/branches/branch%C3%A9 (glob) fetching revision log for "/branches/branch\xc3\xa9" from 5 to 0 (esc) parsing revision 5 (1 changes) reparent to file:/*/$TESTTMP/svn-repo (glob) reparent to file:/*/$TESTTMP/svn-repo/branches/branch%C3%A9 (glob) found parent of branch /branches/branch\xc3\xa9 at 4: /trunk (esc) scanning: 3/4 revisions (75.00%) reparent to file:/*/$TESTTMP/svn-repo/branches/branch%C3%A9e (glob) fetching revision log for "/branches/branch\xc3\xa9e" from 6 to 0 (esc) parsing revision 6 (1 changes) reparent to file:/*/$TESTTMP/svn-repo (glob) reparent to file:/*/$TESTTMP/svn-repo/branches/branch%C3%A9e (glob) found parent of branch /branches/branch\xc3\xa9e at 5: /branches/branch\xc3\xa9 (esc) scanning: 4/4 revisions (100.00%) scanning: 5/4 revisions (125.00%) scanning: 6/4 revisions (150.00%) sorting... converting... 5 init projA source: svn:afeb9c47-92ff-4c0c-9f72-e1f6eb8ac9af/trunk@1 converting: 0/6 revisions (0.00%) committing changelog updating the branch cache 4 hello source: svn:afeb9c47-92ff-4c0c-9f72-e1f6eb8ac9af/trunk@2 converting: 1/6 revisions (16.67%) reparent to file:/*/$TESTTMP/svn-repo/trunk (glob) scanning paths: /trunk/\xc3\xa0 0/3 paths (0.00%) (esc) scanning paths: /trunk/\xc3\xa0/e\xcc\x81 1/3 paths (33.33%) (esc) scanning paths: /trunk/\xc3\xa9 2/3 paths (66.67%) (esc) committing files: \xc3\xa0/e\xcc\x81 (esc) getting files: \xc3\xa0/e\xcc\x81 1/2 files (50.00%) (esc) \xc3\xa9 (esc) getting files: \xc3\xa9 2/2 files (100.00%) (esc) committing manifest committing changelog updating the branch cache 3 copy files source: svn:afeb9c47-92ff-4c0c-9f72-e1f6eb8ac9af/trunk@3 converting: 2/6 revisions (33.33%) scanning paths: /trunk/\xc3\xa0 0/4 paths (0.00%) (esc) gone from -1 reparent to file:/*/$TESTTMP/svn-repo (glob) reparent to file:/*/$TESTTMP/svn-repo/trunk (glob) scanning paths: /trunk/\xc3\xa8 1/4 paths (25.00%) (esc) copied to \xc3\xa8 from \xc3\xa9@2 (esc) scanning paths: /trunk/\xc3\xa9 2/4 paths (50.00%) (esc) gone from -1 reparent to file:/*/$TESTTMP/svn-repo (glob) reparent to file:/*/$TESTTMP/svn-repo/trunk (glob) scanning paths: /trunk/\xc3\xb9 3/4 paths (75.00%) (esc) mark /trunk/\xc3\xb9 came from \xc3\xa0:2 (esc) getting files: \xc3\xa0/e\xcc\x81 1/4 files (25.00%) (esc) getting files: \xc3\xa9 2/4 files (50.00%) (esc) committing files: \xc3\xa8 (esc) getting files: \xc3\xa8 3/4 files (75.00%) (esc) \xc3\xa8: copy \xc3\xa9:6b67ccefd5ce6de77e7ead4f5292843a0255329f (esc) \xc3\xb9/e\xcc\x81 (esc) getting files: \xc3\xb9/e\xcc\x81 4/4 files (100.00%) (esc) \xc3\xb9/e\xcc\x81: copy \xc3\xa0/e\xcc\x81:a9092a3d84a37b9993b5c73576f6de29b7ea50f6 (esc) committing manifest committing changelog updating the branch cache 2 remove files source: svn:afeb9c47-92ff-4c0c-9f72-e1f6eb8ac9af/trunk@4 converting: 3/6 revisions (50.00%) scanning paths: /trunk/\xc3\xa8 0/2 paths (0.00%) (esc) gone from -1 reparent to file:/*/$TESTTMP/svn-repo (glob) reparent to file:/*/$TESTTMP/svn-repo/trunk (glob) scanning paths: /trunk/\xc3\xb9 1/2 paths (50.00%) (esc) gone from -1 reparent to file:/*/$TESTTMP/svn-repo (glob) reparent to file:/*/$TESTTMP/svn-repo/trunk (glob) getting files: \xc3\xa8 1/2 files (50.00%) (esc) getting files: \xc3\xb9/e\xcc\x81 2/2 files (100.00%) (esc) committing files: committing manifest committing changelog updating the branch cache 1 branch to branch? source: svn:afeb9c47-92ff-4c0c-9f72-e1f6eb8ac9af/branches/branch?@5 converting: 4/6 revisions (66.67%) reparent to file:/*/$TESTTMP/svn-repo/branches/branch%C3%A9 (glob) scanning paths: /branches/branch\xc3\xa9 0/1 paths (0.00%) (esc) committing changelog updating the branch cache 0 branch to branch?e source: svn:afeb9c47-92ff-4c0c-9f72-e1f6eb8ac9af/branches/branch?e@6 converting: 5/6 revisions (83.33%) reparent to file:/*/$TESTTMP/svn-repo/branches/branch%C3%A9e (glob) scanning paths: /branches/branch\xc3\xa9e 0/1 paths (0.00%) (esc) committing changelog updating the branch cache reparent to file:/*/$TESTTMP/svn-repo (glob) reparent to file:/*/$TESTTMP/svn-repo/branches/branch%C3%A9e (glob) reparent to file:/*/$TESTTMP/svn-repo (glob) reparent to file:/*/$TESTTMP/svn-repo/branches/branch%C3%A9e (glob) updating tags committing files: .hgtags committing manifest committing changelog updating the branch cache run hg sink post-conversion action $ cd A-hg $ hg up 1 files updated, 0 files merged, 0 files removed, 0 files unresolved Check tags are in UTF-8 $ cat .hgtags e94e4422020e715add80525e8f0f46c9968689f1 branch\xc3\xa9e (esc) f7e66f98380ed1e53a797c5c7a7a2616a7ab377d branch\xc3\xa9 (esc) $ cd ..