Mercurial > hg
view tests/test-fncache.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 | 8ac0c9cd4c48 |
children | 0a57945aaf7f |
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#require repofncache Init repo1: $ hg init repo1 $ cd repo1 $ echo "some text" > a $ hg add adding a $ hg ci -m first $ cat .hg/store/fncache | sort data/a.i Testing a.i/b: $ mkdir a.i $ echo "some other text" > a.i/b $ hg add adding a.i/b $ hg ci -m second $ cat .hg/store/fncache | sort data/a.i data/a.i.hg/b.i Testing a.i.hg/c: $ mkdir a.i.hg $ echo "yet another text" > a.i.hg/c $ hg add adding a.i.hg/c $ hg ci -m third $ cat .hg/store/fncache | sort data/a.i data/a.i.hg.hg/c.i data/a.i.hg/b.i Testing verify: $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files 3 files, 3 changesets, 3 total revisions $ rm .hg/store/fncache $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files warning: revlog 'data/a.i' not in fncache! warning: revlog 'data/a.i.hg/c.i' not in fncache! warning: revlog 'data/a.i/b.i' not in fncache! 3 files, 3 changesets, 3 total revisions 3 warnings encountered! hint: run "hg debugrebuildfncache" to recover from corrupt fncache Follow the hint to make sure it works $ hg debugrebuildfncache adding data/a.i adding data/a.i.hg/c.i adding data/a.i/b.i 3 items added, 0 removed from fncache $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files 3 files, 3 changesets, 3 total revisions $ cd .. Non store repo: $ hg --config format.usestore=False init foo $ cd foo $ mkdir tst.d $ echo foo > tst.d/foo $ hg ci -Amfoo adding tst.d/foo $ find .hg | sort .hg .hg/00changelog.i .hg/00manifest.i .hg/cache .hg/cache/branch2-served .hg/cache/rbc-names-v1 .hg/cache/rbc-revs-v1 .hg/data .hg/data/tst.d.hg .hg/data/tst.d.hg/foo.i .hg/dirstate .hg/fsmonitor.state (fsmonitor !) .hg/last-message.txt .hg/phaseroots .hg/requires .hg/undo .hg/undo.backup.dirstate .hg/undo.backupfiles .hg/undo.bookmarks .hg/undo.branch .hg/undo.desc .hg/undo.dirstate .hg/undo.phaseroots $ cd .. Non fncache repo: $ hg --config format.usefncache=False init bar $ cd bar $ mkdir tst.d $ echo foo > tst.d/Foo $ hg ci -Amfoo adding tst.d/Foo $ find .hg | sort .hg .hg/00changelog.i .hg/cache .hg/cache/branch2-served .hg/cache/rbc-names-v1 .hg/cache/rbc-revs-v1 .hg/dirstate .hg/fsmonitor.state (fsmonitor !) .hg/last-message.txt .hg/requires .hg/store .hg/store/00changelog.i .hg/store/00manifest.i .hg/store/data .hg/store/data/tst.d.hg .hg/store/data/tst.d.hg/_foo.i .hg/store/phaseroots .hg/store/undo .hg/store/undo.backupfiles .hg/store/undo.phaseroots .hg/undo.backup.dirstate .hg/undo.bookmarks .hg/undo.branch .hg/undo.desc .hg/undo.dirstate $ cd .. Encoding of reserved / long paths in the store $ hg init r2 $ cd r2 $ cat <<EOF > .hg/hgrc > [ui] > portablefilenames = ignore > EOF $ hg import -q --bypass - <<EOF > # HG changeset patch > # User test > # Date 0 0 > # Node ID 1c7a2f7cb77be1a0def34e4c7cabc562ad98fbd7 > # Parent 0000000000000000000000000000000000000000 > 1 > > diff --git a/12345678/12345678/12345678/12345678/12345678/12345678/12345678/12345/xxxxxxxxx-xxxxxxxxx-xxxxxxxxx-123456789-12.3456789-12345-ABCDEFGHIJKLMNOPRSTUVWXYZ-abcdefghjiklmnopqrstuvwxyz b/12345678/12345678/12345678/12345678/12345678/12345678/12345678/12345/xxxxxxxxx-xxxxxxxxx-xxxxxxxxx-123456789-12.3456789-12345-ABCDEFGHIJKLMNOPRSTUVWXYZ-abcdefghjiklmnopqrstuvwxyz > new file mode 100644 > --- /dev/null > +++ b/12345678/12345678/12345678/12345678/12345678/12345678/12345678/12345/xxxxxxxxx-xxxxxxxxx-xxxxxxxxx-123456789-12.3456789-12345-ABCDEFGHIJKLMNOPRSTUVWXYZ-abcdefghjiklmnopqrstuvwxyz > @@ -0,0 +1,1 @@ > +foo > diff --git a/AUX/SECOND/X.PRN/FOURTH/FI:FTH/SIXTH/SEVENTH/EIGHTH/NINETH/TENTH/ELEVENTH/LOREMIPSUM.TXT b/AUX/SECOND/X.PRN/FOURTH/FI:FTH/SIXTH/SEVENTH/EIGHTH/NINETH/TENTH/ELEVENTH/LOREMIPSUM.TXT > new file mode 100644 > --- /dev/null > +++ b/AUX/SECOND/X.PRN/FOURTH/FI:FTH/SIXTH/SEVENTH/EIGHTH/NINETH/TENTH/ELEVENTH/LOREMIPSUM.TXT > @@ -0,0 +1,1 @@ > +foo > diff --git a/Project Planning/Resources/AnotherLongDirectoryName/Followedbyanother/AndAnother/AndThenAnExtremelyLongFileName.txt b/Project Planning/Resources/AnotherLongDirectoryName/Followedbyanother/AndAnother/AndThenAnExtremelyLongFileName.txt > new file mode 100644 > --- /dev/null > +++ b/Project Planning/Resources/AnotherLongDirectoryName/Followedbyanother/AndAnother/AndThenAnExtremelyLongFileName.txt > @@ -0,0 +1,1 @@ > +foo > diff --git a/bla.aux/prn/PRN/lpt/com3/nul/coma/foo.NUL/normal.c b/bla.aux/prn/PRN/lpt/com3/nul/coma/foo.NUL/normal.c > new file mode 100644 > --- /dev/null > +++ b/bla.aux/prn/PRN/lpt/com3/nul/coma/foo.NUL/normal.c > @@ -0,0 +1,1 @@ > +foo > diff --git a/enterprise/openesbaddons/contrib-imola/corba-bc/netbeansplugin/wsdlExtension/src/main/java/META-INF/services/org.netbeans.modules.xml.wsdl.bindingsupport.spi.ExtensibilityElementTemplateProvider b/enterprise/openesbaddons/contrib-imola/corba-bc/netbeansplugin/wsdlExtension/src/main/java/META-INF/services/org.netbeans.modules.xml.wsdl.bindingsupport.spi.ExtensibilityElementTemplateProvider > new file mode 100644 > --- /dev/null > +++ b/enterprise/openesbaddons/contrib-imola/corba-bc/netbeansplugin/wsdlExtension/src/main/java/META-INF/services/org.netbeans.modules.xml.wsdl.bindingsupport.spi.ExtensibilityElementTemplateProvider > @@ -0,0 +1,1 @@ > +foo > EOF $ find .hg/store -name *.i | sort .hg/store/00changelog.i .hg/store/00manifest.i .hg/store/data/bla.aux/pr~6e/_p_r_n/lpt/co~6d3/nu~6c/coma/foo._n_u_l/normal.c.i .hg/store/dh/12345678/12345678/12345678/12345678/12345678/12345678/12345678/12345/xxxxxx168e07b38e65eff86ab579afaaa8e30bfbe0f35f.i .hg/store/dh/au~78/second/x.prn/fourth/fi~3afth/sixth/seventh/eighth/nineth/tenth/loremia20419e358ddff1bf8751e38288aff1d7c32ec05.i .hg/store/dh/enterpri/openesba/contrib-/corba-bc/netbeans/wsdlexte/src/main/java/org.net7018f27961fdf338a598a40c4683429e7ffb9743.i .hg/store/dh/project_/resource/anotherl/followed/andanoth/andthenanextremelylongfilename0d8e1f4187c650e2f1fdca9fd90f786bc0976b6b.i $ cd .. Aborting lock does not prevent fncache writes $ cat > exceptionext.py <<EOF > from __future__ import absolute_import > import os > from mercurial import commands, error, extensions > > def lockexception(orig, vfs, lockname, wait, releasefn, *args, **kwargs): > def releasewrap(): > l.held = False # ensure __del__ is a noop > raise error.Abort("forced lock failure") > l = orig(vfs, lockname, wait, releasewrap, *args, **kwargs) > return l > > def reposetup(ui, repo): > extensions.wrapfunction(repo, '_lock', lockexception) > > cmdtable = {} > > # wrap "commit" command to prevent wlock from being '__del__()'-ed > # at the end of dispatching (for intentional "forced lcok failure") > def commitwrap(orig, ui, repo, *pats, **opts): > repo = repo.unfiltered() # to use replaced repo._lock certainly > wlock = repo.wlock() > try: > return orig(ui, repo, *pats, **opts) > finally: > # multiple 'relase()' is needed for complete releasing wlock, > # because "forced" abort at last releasing store lock > # prevents wlock from being released at same 'lockmod.release()' > for i in range(wlock.held): > wlock.release() > > def extsetup(ui): > extensions.wrapcommand(commands.table, b"commit", commitwrap) > EOF $ extpath=`pwd`/exceptionext.py $ hg init fncachetxn $ cd fncachetxn $ printf "[extensions]\nexceptionext=$extpath\n" >> .hg/hgrc $ touch y $ hg ci -qAm y abort: forced lock failure [255] $ cat .hg/store/fncache data/y.i Aborting transaction prevents fncache change $ cat > ../exceptionext.py <<EOF > from __future__ import absolute_import > import os > from mercurial import commands, error, extensions, localrepo > > def wrapper(orig, self, *args, **kwargs): > tr = orig(self, *args, **kwargs) > def fail(tr): > raise error.Abort(b"forced transaction failure") > # zzz prefix to ensure it sorted after store.write > tr.addfinalize(b'zzz-forcefails', fail) > return tr > > def uisetup(ui): > extensions.wrapfunction( > localrepo.localrepository, b'transaction', wrapper) > > cmdtable = {} > > EOF Clean cached version $ rm -f "${extpath}c" $ rm -Rf "`dirname $extpath`/__pycache__" $ touch z $ hg ci -qAm z transaction abort! rollback completed abort: forced transaction failure [255] $ cat .hg/store/fncache data/y.i Aborted transactions can be recovered later $ cat > ../exceptionext.py <<EOF > from __future__ import absolute_import > import os > from mercurial import ( > commands, > error, > extensions, > localrepo, > transaction, > ) > > def trwrapper(orig, self, *args, **kwargs): > tr = orig(self, *args, **kwargs) > def fail(tr): > raise error.Abort("forced transaction failure") > # zzz prefix to ensure it sorted after store.write > tr.addfinalize('zzz-forcefails', fail) > return tr > > def abortwrapper(orig, self, *args, **kwargs): > raise error.Abort("forced transaction failure") > > def uisetup(ui): > extensions.wrapfunction(localrepo.localrepository, 'transaction', > trwrapper) > extensions.wrapfunction(transaction.transaction, '_abort', > abortwrapper) > > cmdtable = {} > > EOF Clean cached versions $ rm -f "${extpath}c" $ rm -Rf "`dirname $extpath`/__pycache__" $ hg up -q 1 $ touch z $ hg ci -qAm z 2>/dev/null [255] $ cat .hg/store/fncache | sort data/y.i data/z.i $ hg recover rolling back interrupted transaction checking changesets checking manifests crosschecking files in changesets and manifests checking files 1 files, 1 changesets, 1 total revisions $ cat .hg/store/fncache data/y.i $ cd .. debugrebuildfncache does nothing unless repo has fncache requirement $ hg --config format.usefncache=false init nofncache $ cd nofncache $ hg debugrebuildfncache (not rebuilding fncache because repository does not support fncache) $ cd .. debugrebuildfncache works on empty repository $ hg init empty $ cd empty $ hg debugrebuildfncache fncache already up to date $ cd .. debugrebuildfncache on an up to date repository no-ops $ hg init repo $ cd repo $ echo initial > foo $ echo initial > .bar $ hg commit -A -m initial adding .bar adding foo $ cat .hg/store/fncache | sort data/.bar.i data/foo.i $ hg debugrebuildfncache fncache already up to date debugrebuildfncache restores deleted fncache file $ rm -f .hg/store/fncache $ hg debugrebuildfncache adding data/.bar.i adding data/foo.i 2 items added, 0 removed from fncache $ cat .hg/store/fncache | sort data/.bar.i data/foo.i Rebuild after rebuild should no-op $ hg debugrebuildfncache fncache already up to date A single missing file should get restored, an extra file should be removed $ cat > .hg/store/fncache << EOF > data/foo.i > data/bad-entry.i > EOF $ hg debugrebuildfncache removing data/bad-entry.i adding data/.bar.i 1 items added, 1 removed from fncache $ cat .hg/store/fncache | sort data/.bar.i data/foo.i $ cd .. Try a simple variation without dotencode to ensure fncache is ignorant of encoding $ hg --config format.dotencode=false init nodotencode $ cd nodotencode $ echo initial > foo $ echo initial > .bar $ hg commit -A -m initial adding .bar adding foo $ cat .hg/store/fncache | sort data/.bar.i data/foo.i $ rm .hg/store/fncache $ hg debugrebuildfncache adding data/.bar.i adding data/foo.i 2 items added, 0 removed from fncache $ cat .hg/store/fncache | sort data/.bar.i data/foo.i $ cd .. In repositories that have accumulated a large number of files over time, the fncache file is going to be large. If we possibly can avoid loading it, so much the better. The cache should not loaded when committing changes to existing files, or when unbundling changesets that only contain changes to existing files: $ cat > fncacheloadwarn.py << EOF > from __future__ import absolute_import > from mercurial import extensions, store > > def extsetup(ui): > def wrapstore(orig, requirements, *args): > store = orig(requirements, *args) > if 'store' in requirements and 'fncache' in requirements: > instrumentfncachestore(store, ui) > return store > extensions.wrapfunction(store, 'store', wrapstore) > > def instrumentfncachestore(fncachestore, ui): > class instrumentedfncache(type(fncachestore.fncache)): > def _load(self): > ui.warn('fncache load triggered!\n') > super(instrumentedfncache, self)._load() > fncachestore.fncache.__class__ = instrumentedfncache > EOF $ fncachextpath=`pwd`/fncacheloadwarn.py $ hg init nofncacheload $ cd nofncacheload $ printf "[extensions]\nfncacheloadwarn=$fncachextpath\n" >> .hg/hgrc A new file should trigger a load, as we'd want to update the fncache set in that case: $ touch foo $ hg ci -qAm foo fncache load triggered! But modifying that file should not: $ echo bar >> foo $ hg ci -qm foo If a transaction has been aborted, the zero-size truncated index file will not prevent the fncache from being loaded; rather than actually abort a transaction, we simulate the situation by creating a zero-size index file: $ touch .hg/store/data/bar.i $ touch bar $ hg ci -qAm bar fncache load triggered! Unbundling should follow the same rules; existing files should not cause a load: $ hg clone -q . tobundle $ echo 'new line' > tobundle/bar $ hg -R tobundle ci -qm bar $ hg -R tobundle bundle -q barupdated.hg $ hg unbundle -q barupdated.hg but adding new files should: $ touch tobundle/newfile $ hg -R tobundle ci -qAm newfile $ hg -R tobundle bundle -q newfile.hg $ hg unbundle -q newfile.hg fncache load triggered! $ cd ..