Mercurial > hg
view tests/test-merge-local.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 | a2804ddcf9ae |
children | 69ffbbe73dd0 |
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$ hg init Revision 0: $ echo "unchanged" > unchanged $ echo "remove me" > remove $ echo "copy me" > copy $ echo "move me" > move $ for i in 1 2 3 4 5 6 7 8 9; do > echo "merge ok $i" >> zzz1_merge_ok > done $ echo "merge bad" > zzz2_merge_bad $ hg ci -Am "revision 0" adding copy adding move adding remove adding unchanged adding zzz1_merge_ok adding zzz2_merge_bad Revision 1: $ hg rm remove $ hg mv move moved $ hg cp copy copied $ echo "added" > added $ hg add added $ echo "new first line" > zzz1_merge_ok $ hg cat zzz1_merge_ok >> zzz1_merge_ok $ echo "new last line" >> zzz2_merge_bad $ hg ci -m "revision 1" Local changes to revision 0: $ hg co 0 4 files updated, 0 files merged, 3 files removed, 0 files unresolved $ echo "new last line" >> zzz1_merge_ok $ echo "another last line" >> zzz2_merge_bad $ hg diff --nodates | grep "^[+-][^<>]" --- a/zzz1_merge_ok +++ b/zzz1_merge_ok +new last line --- a/zzz2_merge_bad +++ b/zzz2_merge_bad +another last line $ hg st M zzz1_merge_ok M zzz2_merge_bad Local merge with bad merge tool: $ HGMERGE=false hg co merging zzz1_merge_ok merging zzz2_merge_bad merging zzz2_merge_bad failed! 3 files updated, 1 files merged, 2 files removed, 1 files unresolved use 'hg resolve' to retry unresolved file merges [1] $ hg resolve -m (no more unresolved files) $ hg co 0 merging zzz1_merge_ok merging zzz2_merge_bad warning: conflicts while merging zzz2_merge_bad! (edit, then use 'hg resolve --mark') 2 files updated, 1 files merged, 2 files removed, 1 files unresolved use 'hg resolve' to retry unresolved file merges [1] $ hg diff --nodates | grep "^[+-][^<>]" --- a/zzz1_merge_ok +++ b/zzz1_merge_ok +new last line --- a/zzz2_merge_bad +++ b/zzz2_merge_bad +another last line +======= $ hg st M zzz1_merge_ok M zzz2_merge_bad ? zzz2_merge_bad.orig Local merge with conflicts: $ hg resolve -m (no more unresolved files) $ hg co merging zzz1_merge_ok merging zzz2_merge_bad warning: conflicts while merging zzz2_merge_bad! (edit, then use 'hg resolve --mark') 3 files updated, 1 files merged, 2 files removed, 1 files unresolved use 'hg resolve' to retry unresolved file merges [1] $ hg resolve -m (no more unresolved files) $ hg co 0 --config 'ui.origbackuppath=.hg/origbackups' merging zzz1_merge_ok merging zzz2_merge_bad warning: conflicts while merging zzz2_merge_bad! (edit, then use 'hg resolve --mark') 2 files updated, 1 files merged, 2 files removed, 1 files unresolved use 'hg resolve' to retry unresolved file merges [1] Are orig files from the last commit where we want them? $ ls .hg/origbackups zzz2_merge_bad.orig $ hg diff --nodates | grep "^[+-][^<>]" --- a/zzz1_merge_ok +++ b/zzz1_merge_ok +new last line --- a/zzz2_merge_bad +++ b/zzz2_merge_bad +another last line +======= +======= +new last line +======= $ hg st M zzz1_merge_ok M zzz2_merge_bad ? zzz2_merge_bad.orig Local merge without conflicts: $ hg revert zzz2_merge_bad $ hg resolve -m (no more unresolved files) $ hg co merging zzz1_merge_ok 4 files updated, 1 files merged, 2 files removed, 0 files unresolved $ hg diff --nodates | grep "^[+-][^<>]" --- a/zzz1_merge_ok +++ b/zzz1_merge_ok +new last line $ hg st M zzz1_merge_ok ? zzz2_merge_bad.orig