Mercurial > hg
view tests/test-rebuildstate.t @ 30212:260af19891f2
changegroup: increase write buffer size to 128k
By default, Python defers to the operating system for choosing the
default buffer size on opened files. On my Linux machine, the default
is 4k, which is really small for 2016.
This patch bumps the write buffer size when writing
changegroups/bundles to 128k. This matches the 128k read buffer
we already use on revlogs.
It's worth noting that this only impacts when writing to an explicit
file (such as during `hg bundle`). Buffers when writing to bundle
files via the repo vfs or to a temporary file are not impacted.
When producing a none-v2 bundle file of the mozilla-unified repository,
this change caused the number of write() system calls to drop from
952,449 to 29,788. After this change, the most frequent system
calls are fstat(), read(), lseek(), and open(). There were
2,523,672 system calls after this patch (so a net decrease of
~950k is statistically significant).
This change shows no performance change on my system. But I have a
high-end system with a fast SSD. It is quite possible this change
will have a significant impact on network file systems, where
extra network round trips due to excessive I/O system calls could
introduce significant latency.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sun, 16 Oct 2016 13:35:23 -0700 |
parents | ba06562a06a2 |
children | 46ba2cdda476 |
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$ cat > adddrop.py <<EOF > from mercurial import cmdutil > cmdtable = {} > command = cmdutil.command(cmdtable) > @command('debugadddrop', > [('', 'drop', False, 'drop file from dirstate', 'FILE'), > ('', 'normal-lookup', False, 'add file to dirstate', 'FILE')], > 'hg debugadddrop') > def debugadddrop(ui, repo, *pats, **opts): > '''Add or drop unnamed arguments to or from the dirstate''' > drop = opts.get('drop') > nl = opts.get('normal_lookup') > if nl and drop: > raise error.Abort('drop and normal-lookup are mutually exclusive') > wlock = repo.wlock() > try: > for file in pats: > if opts.get('normal_lookup'): > repo.dirstate.normallookup(file) > else: > repo.dirstate.drop(file) > > repo.dirstate.write(repo.currenttransaction()) > finally: > wlock.release() > EOF $ echo "[extensions]" >> $HGRCPATH $ echo "debugadddrop=`pwd`/adddrop.py" >> $HGRCPATH basic test for hg debugrebuildstate $ hg init repo $ cd repo $ touch foo bar $ hg ci -Am 'add foo bar' adding bar adding foo $ touch baz $ hg add baz $ hg rm bar $ hg debugrebuildstate state dump after $ hg debugstate --nodates | sort n 0 -1 unset bar n 0 -1 unset foo $ hg debugadddrop --normal-lookup file1 file2 $ hg debugadddrop --drop bar $ hg debugadddrop --drop $ hg debugstate --nodates n 0 -1 unset file1 n 0 -1 unset file2 n 0 -1 unset foo $ hg debugrebuildstate status $ hg st -A ! bar ? baz C foo Test debugdirstate --minimal where a file is not in parent manifest but in the dirstate $ touch foo bar qux $ hg add qux $ hg remove bar $ hg status -A A qux R bar ? baz C foo $ hg debugadddrop --normal-lookup baz $ hg debugdirstate --nodates r 0 0 * bar (glob) n 0 -1 * baz (glob) n 644 0 * foo (glob) a 0 -1 * qux (glob) $ hg debugrebuilddirstate --minimal $ hg debugdirstate --nodates r 0 0 * bar (glob) n 644 0 * foo (glob) a 0 -1 * qux (glob) $ hg status -A A qux R bar ? baz C foo Test debugdirstate --minimal where file is in the parent manifest but not the dirstate $ hg manifest bar foo $ hg status -A A qux R bar ? baz C foo $ hg debugdirstate --nodates r 0 0 * bar (glob) n 644 0 * foo (glob) a 0 -1 * qux (glob) $ hg debugadddrop --drop foo $ hg debugdirstate --nodates r 0 0 * bar (glob) a 0 -1 * qux (glob) $ hg debugrebuilddirstate --minimal $ hg debugdirstate --nodates r 0 0 * bar (glob) n 0 -1 * foo (glob) a 0 -1 * qux (glob) $ hg status -A A qux R bar ? baz C foo