Mercurial > hg
view tests/test-copy-move-merge.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 | 978b907d9b36 |
children | 3b7cb3d17137 |
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$ hg init t $ cd t $ echo 1 > a $ hg ci -qAm "first" $ hg cp a b $ hg mv a c $ echo 2 >> b $ echo 2 >> c $ hg ci -qAm "second" $ hg co -C 0 1 files updated, 0 files merged, 2 files removed, 0 files unresolved $ echo 0 > a $ echo 1 >> a $ hg ci -qAm "other" $ hg merge --debug searching for copies back to rev 1 unmatched files in other: b c all copies found (* = to merge, ! = divergent, % = renamed and deleted): src: 'a' -> dst: 'b' * src: 'a' -> dst: 'c' * checking for directory renames resolving manifests branchmerge: True, force: False, partial: False ancestor: b8bf91eeebbc, local: add3f11052fa+, remote: 17c05bb7fcb6 preserving a for resolve of b preserving a for resolve of c removing a starting 4 threads for background file closing (?) b: remote moved from a -> m (premerge) picked tool ':merge' for b (binary False symlink False changedelete False) merging a and b to b my b@add3f11052fa+ other b@17c05bb7fcb6 ancestor a@b8bf91eeebbc premerge successful c: remote moved from a -> m (premerge) picked tool ':merge' for c (binary False symlink False changedelete False) merging a and c to c my c@add3f11052fa+ other c@17c05bb7fcb6 ancestor a@b8bf91eeebbc premerge successful 0 files updated, 2 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) file b $ cat b 0 1 2 file c $ cat c 0 1 2 Test disabling copy tracing - first verify copy metadata was kept $ hg up -qC 2 $ hg rebase --keep -d 1 -b 2 --config extensions.rebase= rebasing 2:add3f11052fa "other" (tip) merging b and a to b merging c and a to c $ cat b 0 1 2 - next verify copy metadata is lost when disabled $ hg strip -r . --config extensions.strip= 2 files updated, 0 files merged, 0 files removed, 0 files unresolved saved backup bundle to $TESTTMP/t/.hg/strip-backup/550bd84c0cd3-fc575957-backup.hg (glob) $ hg up -qC 2 $ hg rebase --keep -d 1 -b 2 --config extensions.rebase= --config experimental.disablecopytrace=True --config ui.interactive=True << EOF > c > EOF rebasing 2:add3f11052fa "other" (tip) other [source] changed a which local [dest] deleted use (c)hanged version, leave (d)eleted, or leave (u)nresolved? c $ cat b 1 2 $ cd .. Verify disabling copy tracing still keeps copies from rebase source $ hg init copydisable $ cd copydisable $ touch a $ hg ci -Aqm 'add a' $ touch b $ hg ci -Aqm 'add b, c' $ hg cp b x $ echo x >> x $ hg ci -qm 'copy b->x' $ hg up -q 1 $ touch z $ hg ci -Aqm 'add z' $ hg log -G -T '{rev} {desc}\n' @ 3 add z | | o 2 copy b->x |/ o 1 add b, c | o 0 add a $ hg rebase -d . -b 2 --config extensions.rebase= --config experimental.disablecopytrace=True rebasing 2:6adcf8c12e7d "copy b->x" saved backup bundle to $TESTTMP/copydisable/.hg/strip-backup/6adcf8c12e7d-ce4b3e75-backup.hg (glob) $ hg up -q 3 $ hg log -f x -T '{rev} {desc}\n' 3 copy b->x 1 add b, c $ cd ../ Verify we duplicate existing copies, instead of detecting them $ hg init copydisable3 $ cd copydisable3 $ touch a $ hg ci -Aqm 'add a' $ hg cp a b $ hg ci -Aqm 'copy a->b' $ hg mv b c $ hg ci -Aqm 'move b->c' $ hg up -q 0 $ hg cp a b $ echo b >> b $ hg ci -Aqm 'copy a->b (2)' $ hg log -G -T '{rev} {desc}\n' @ 3 copy a->b (2) | | o 2 move b->c | | | o 1 copy a->b |/ o 0 add a $ hg rebase -d 2 -s 3 --config extensions.rebase= --config experimental.disablecopytrace=True rebasing 3:47e1a9e6273b "copy a->b (2)" (tip) saved backup bundle to $TESTTMP/copydisable3/.hg/strip-backup/47e1a9e6273b-2d099c59-backup.hg (glob) $ hg log -G -f b @ changeset: 3:76024fb4b05b : tag: tip : user: test : date: Thu Jan 01 00:00:00 1970 +0000 : summary: copy a->b (2) : o changeset: 0:ac82d8b1f7c4 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: add a