Mercurial > hg
view tests/test-mq-qqueue.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 | 4f2f0f367ef6 |
children |
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$ echo "[extensions]" >> $HGRCPATH $ echo "mq=" >> $HGRCPATH $ hg init foo $ cd foo $ echo a > a $ hg ci -qAm a Default queue: $ hg qqueue patches (active) $ echo b > a $ hg qnew -fgDU somestuff Applied patches in default queue: $ hg qap somestuff Try to change patch (create succeeds, switch fails): $ hg qqueue foo --create abort: new queue created, but cannot make active as patches are applied [255] $ hg qqueue foo patches (active) Empty default queue: $ hg qpop popping somestuff patch queue now empty Switch queue: $ hg qqueue foo $ hg qqueue foo (active) patches List queues, quiet: $ hg qqueue --quiet foo patches Fail creating queue with already existing name: $ hg qqueue --create foo abort: queue "foo" already exists [255] $ hg qqueue foo (active) patches Create new queue for rename: $ hg qqueue --create bar $ hg qqueue bar (active) foo patches Rename queue, same name: $ hg qqueue --rename bar abort: can't rename "bar" to its current name [255] Rename queue to existing: $ hg qqueue --rename foo abort: queue "foo" already exists [255] Rename queue: $ hg qqueue --rename buz $ hg qqueue buz (active) foo patches Switch back to previous queue: $ hg qqueue foo $ hg qqueue --delete buz $ hg qqueue foo (active) patches Create queue for purge: $ hg qqueue --create purge-me $ hg qqueue foo patches purge-me (active) Create patch for purge: $ hg qnew patch-purge-me $ ls -1d .hg/patches-purge-me 2>/dev/null || true .hg/patches-purge-me $ hg qpop -a popping patch-purge-me patch queue now empty Purge queue: $ hg qqueue foo $ hg qqueue --purge purge-me $ hg qqueue foo (active) patches $ ls -1d .hg/patches-purge-me 2>/dev/null || true Unapplied patches: $ hg qun $ echo c > a $ hg qnew -fgDU otherstuff Fail switching back: $ hg qqueue patches abort: new queue created, but cannot make active as patches are applied [255] Fail deleting current: $ hg qqueue foo --delete abort: cannot delete currently active queue [255] Switch back and delete foo: $ hg qpop -a popping otherstuff patch queue now empty $ hg qqueue patches $ hg qqueue foo --delete $ hg qqueue patches (active) Tricky cases: $ hg qqueue store --create $ hg qnew journal $ hg qqueue patches store (active) $ hg qpop -a popping journal patch queue now empty $ hg qqueue patches $ hg qun somestuff Invalid names: $ hg qqueue test/../../bar --create abort: invalid queue name, may not contain the characters ":\/." [255] $ hg qqueue . --create abort: invalid queue name, may not contain the characters ":\/." [255] $ cd ..