Mercurial > hg
view tests/test-subrepo-relative-path.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 | c63bf97cf7c7 |
children | 2428e8ec0793 |
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#require killdaemons Preparing the subrepository 'sub' $ hg init sub $ echo sub > sub/sub $ hg add -R sub adding sub/sub (glob) $ hg commit -R sub -m "sub import" Preparing the 'main' repo which depends on the subrepo 'sub' $ hg init main $ echo main > main/main $ echo "sub = ../sub" > main/.hgsub $ hg clone sub main/sub updating to branch default 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg add -R main adding main/.hgsub (glob) adding main/main (glob) $ hg commit -R main -m "main import" Cleaning both repositories, just as a clone -U $ hg up -C -R sub null 0 files updated, 0 files merged, 1 files removed, 0 files unresolved $ hg up -C -R main null 0 files updated, 0 files merged, 3 files removed, 0 files unresolved $ rm -rf main/sub hide outer repo $ hg init Serving them both using hgweb $ printf '[paths]\n/main = main\nsub = sub\n' > webdir.conf $ hg serve --webdir-conf webdir.conf -a localhost -p $HGPORT \ > -A /dev/null -E /dev/null --pid-file hg.pid -d $ cat hg.pid >> $DAEMON_PIDS Clone main from hgweb $ hg clone "http://localhost:$HGPORT/main" cloned requesting all changes adding changesets adding manifests adding file changes added 1 changesets with 3 changes to 3 files updating to branch default cloning subrepo sub from http://localhost:$HGPORT/sub requesting all changes adding changesets adding manifests adding file changes added 1 changesets with 1 changes to 1 files 3 files updated, 0 files merged, 0 files removed, 0 files unresolved Checking cloned repo ids $ hg id -R cloned fdfeeb3e979e tip $ hg id -R cloned/sub 863c1745b441 tip subrepo debug for 'main' clone $ hg debugsub -R cloned path sub source ../sub revision 863c1745b441bd97a8c4a096e87793073f4fb215 $ killdaemons.py subrepo paths with ssh urls $ hg clone -e "python \"$TESTDIR/dummyssh\"" ssh://user@dummy/cloned sshclone requesting all changes adding changesets adding manifests adding file changes added 1 changesets with 3 changes to 3 files updating to branch default cloning subrepo sub from ssh://user@dummy/sub requesting all changes adding changesets adding manifests adding file changes added 1 changesets with 1 changes to 1 files 3 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg -R sshclone push -e "python \"$TESTDIR/dummyssh\"" ssh://user@dummy/`pwd`/cloned pushing to ssh://user@dummy/$TESTTMP/cloned pushing subrepo sub to ssh://user@dummy/$TESTTMP/sub searching for changes no changes found searching for changes no changes found [1] $ cat dummylog Got arguments 1:user@dummy 2:hg -R cloned serve --stdio Got arguments 1:user@dummy 2:hg -R sub serve --stdio Got arguments 1:user@dummy 2:hg -R $TESTTMP/cloned serve --stdio Got arguments 1:user@dummy 2:hg -R $TESTTMP/sub serve --stdio