Mercurial > hg
view tests/test-lock-badness.t @ 30288:ceddc3d94d74
revlog: inline start() and end() for perf reasons
When I implemented `hg perfrevlogchunks`, one of the things that
stood out was N * _chunk() calls was ~38x slower than 1
_chunks() call. Specifically, on the mozilla-unified repo:
N*_chunk: 0.528997s
1*_chunks: 0.013735s
This repo has 352,097 changesets. So the average time per changeset
comes out to:
N*_chunk: 1.502us
1*_chunks: 0.039us
If you extrapolate these numbers to a repository with 1M changesets,
that comes out to 1.502s versus 0.039s, which is significant.
At these latencies, Python attribute lookups and function calls
matter. So, this patch inlines some code to cut down on that overhead.
The impact of this patch on N*_chunk() calls is clear:
! wall 0.528997 comb 0.520000 user 0.500000 sys 0.020000 (best of 19)
! wall 0.367723 comb 0.370000 user 0.350000 sys 0.020000 (best of 27)
So, we go from ~38x slower to ~27x. A nice improvement. But there's
still a long way to go.
It's worth noting that functionality like revsets perform changelog
lookups one revision at a time. So this code path is worth optimizing.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sat, 22 Oct 2016 15:41:23 -0700 |
parents | 0c8c388c7d62 |
children | 46ba2cdda476 |
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#require unix-permissions no-root no-windows Prepare $ hg init a $ echo a > a/a $ hg -R a ci -A -m a adding a $ hg clone a b updating to branch default 1 files updated, 0 files merged, 0 files removed, 0 files unresolved Test that raising an exception in the release function doesn't cause the lock to choke $ cat > testlock.py << EOF > from mercurial import cmdutil, error, error > > cmdtable = {} > command = cmdutil.command(cmdtable) > > def acquiretestlock(repo, releaseexc): > def unlock(): > if releaseexc: > raise error.Abort('expected release exception') > l = repo._lock(repo.vfs, 'testlock', False, unlock, None, 'test lock') > return l > > @command('testlockexc') > def testlockexc(ui, repo): > testlock = acquiretestlock(repo, True) > try: > testlock.release() > finally: > try: > testlock = acquiretestlock(repo, False) > except error.LockHeld: > raise error.Abort('lockfile on disk even after releasing!') > testlock.release() > EOF $ cat >> $HGRCPATH << EOF > [extensions] > testlock=$TESTTMP/testlock.py > EOF $ hg -R b testlockexc abort: expected release exception [255] One process waiting for another $ cat > hooks.py << EOF > import time > def sleepone(**x): time.sleep(1) > def sleephalf(**x): time.sleep(0.5) > EOF $ echo b > b/b $ hg -R b ci -A -m b --config hooks.precommit="python:`pwd`/hooks.py:sleepone" > stdout & $ hg -R b up -q --config hooks.pre-update="python:`pwd`/hooks.py:sleephalf" \ > > preup 2>&1 $ wait $ cat preup waiting for lock on working directory of b held by process '*' on host '*' (glob) got lock after * seconds (glob) $ cat stdout adding b Pushing to a local read-only repo that can't be locked $ chmod 100 a/.hg/store $ hg -R b push a pushing to a searching for changes abort: could not lock repository a: Permission denied [255] $ chmod 700 a/.hg/store