Mercurial > hg
view mercurial/default.d/mergetools.rc @ 35793:4fb2bb61597c
bundle2: increase payload part chunk size to 32kb
Bundle2 payload parts are framed chunks. Esentially, we obtain
data in equal size chunks of size `preferedchunksize` and emit those
to a generator. That generator is fed into a compressor (which can
be the no-op compressor, which just re-emits the generator). And
the output from the compressor likely goes to a file descriptor
or socket.
What this means is that small chunk sizes create more Python objects
and Python function calls than larger chunk sizes. And as we know,
Python object and function call overhead in performance sensitive
code matters (at least with CPython).
This commit increases the bundle2 part payload chunk size from 4k
to 32k. Practically speaking, this means that the chunks we feed
into a compressor (implemented in C code) or feed directly into a
file handle or socket write() are larger. It's possible the chunks
might be larger than what the receiver can handle in one logical
operation. But at that point, we're in C code, which is much more
efficient at dealing with splitting up the chunk and making multiple
function calls than Python is.
A downside to larger chunks is that the receiver has to wait for that
much data to arrive (either raw or from a decompressor) before it
can process the chunk. But 32kb still feels like a small buffer to
have to wait for. And in many cases, the client will convert from
8 read(4096) to 1 read(32768). That's happening in Python land. So
we cut down on the number of Python objects and function calls,
making the client faster as well. I don't think there are any
significant concerns to increasing the payload chunk size to 32kb.
The impact of this change on performance significant. Using `curl`
to obtain a stream clone bundle2 payload from a server on localhost
serving the mozilla-unified repository:
before: 20.78 user; 7.71 system; 80.5 MB/s
after: 13.90 user; 3.51 system; 132 MB/s
legacy: 9.72 user; 8.16 system; 132 MB/s
bundle2 stream clone generation is still more resource intensive than
legacy stream clone (that's likely because of the use of a
util.chunkbuffer). But the throughput is the same. We might
be in territory we're this is effectively a benchmark of the
networking stack or Python's syscall throughput.
From the client perspective, `hg clone -U --stream`:
before: 33.50 user; 7.95 system; 53.3 MB/s
after: 22.82 user; 7.33 system; 72.7 MB/s
legacy: 29.96 user; 7.94 system; 58.0 MB/s
And for `hg clone --stream` with a working directory update of
~230k files:
after: 119.55 user; 26.47 system; 0:57.08 wall
legacy: 126.98 user; 26.94 system; 1:05.56 wall
So, it appears that bundle2's stream clone is now definitively faster
than legacy stream clone!
Differential Revision: https://phab.mercurial-scm.org/D1932
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sat, 20 Jan 2018 22:55:42 -0800 |
parents | f6e2e42fb8ef |
children | a9802c9ecfb5 |
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# Some default global settings for common merge tools [merge-tools] kdiff3.args=--auto --L1 base --L2 local --L3 other $base $local $other -o $output kdiff3.regkey=Software\KDiff3 kdiff3.regkeyalt=Software\Wow6432Node\KDiff3 kdiff3.regappend=\kdiff3.exe kdiff3.fixeol=True kdiff3.gui=True kdiff3.diffargs=--L1 $plabel1 --L2 $clabel $parent $child gvimdiff.args=--nofork -d -g -O $local $other $base gvimdiff.regkey=Software\Vim\GVim gvimdiff.regkeyalt=Software\Wow6432Node\Vim\GVim gvimdiff.regname=path gvimdiff.priority=-9 gvimdiff.diffargs=--nofork -d -g -O $parent $child vimdiff.args=$local $other $base -c 'redraw | echomsg "hg merge conflict, type \":cq\" to abort vimdiff"' vimdiff.check=changed vimdiff.priority=-10 merge.check=conflicts merge.priority=-100 gpyfm.gui=True meld.gui=True meld.args=--label='local' $local --label='merged' $base --label='other' $other -o $output meld.check=changed meld.diffargs=-a --label=$plabel1 $parent --label=$clabel $child tkdiff.args=$local $other -a $base -o $output tkdiff.gui=True tkdiff.priority=-8 tkdiff.diffargs=-L $plabel1 $parent -L $clabel $child xxdiff.args=--show-merged-pane --exit-with-merge-status --title1 local --title2 base --title3 other --merged-filename $output --merge $local $base $other xxdiff.gui=True xxdiff.priority=-8 xxdiff.diffargs=--title1 $plabel1 $parent --title2 $clabel $child diffmerge.regkey=Software\SourceGear\SourceGear DiffMerge\ diffmerge.regkeyalt=Software\Wow6432Node\SourceGear\SourceGear DiffMerge\ diffmerge.regname=Location diffmerge.priority=-7 diffmerge.args=-nosplash -merge -title1=local -title2=merged -title3=other $local $base $other -result=$output diffmerge.check=changed diffmerge.gui=True diffmerge.diffargs=--nosplash --title1=$plabel1 --title2=$clabel $parent $child p4merge.args=$base $local $other $output p4merge.regkey=Software\Perforce\Environment p4merge.regkeyalt=Software\Wow6432Node\Perforce\Environment p4merge.regname=P4INSTROOT p4merge.regappend=\p4merge.exe p4merge.gui=True p4merge.priority=-8 p4merge.diffargs=$parent $child p4mergeosx.executable = /Applications/p4merge.app/Contents/MacOS/p4merge p4mergeosx.args = $base $local $other $output p4mergeosx.gui = True p4mergeosx.priority=-8 p4mergeosx.diffargs=$parent $child tortoisemerge.args=/base:$base /mine:$local /theirs:$other /merged:$output tortoisemerge.regkey=Software\TortoiseSVN tortoisemerge.regkeyalt=Software\Wow6432Node\TortoiseSVN tortoisemerge.check=changed tortoisemerge.gui=True tortoisemerge.priority=-8 tortoisemerge.diffargs=/base:$parent /mine:$child /basename:$plabel1 /minename:$clabel ecmerge.args=$base $local $other --mode=merge3 --title0=base --title1=local --title2=other --to=$output ecmerge.regkey=Software\Elli\xc3\xa9 Computing\Merge ecmerge.regkeyalt=Software\Wow6432Node\Elli\xc3\xa9 Computing\Merge ecmerge.gui=True ecmerge.diffargs=$parent $child --mode=diff2 --title1=$plabel1 --title2=$clabel # editmerge is a small script shipped in contrib. # It needs this config otherwise it behaves the same as internal:local editmerge.args=$output editmerge.check=changed editmerge.premerge=keep filemerge.executable=/Developer/Applications/Utilities/FileMerge.app/Contents/MacOS/FileMerge filemerge.args=-left $other -right $local -ancestor $base -merge $output filemerge.gui=True filemergexcode.executable=/Applications/Xcode.app/Contents/Applications/FileMerge.app/Contents/MacOS/FileMerge filemergexcode.args=-left $other -right $local -ancestor $base -merge $output filemergexcode.gui=True ; Windows version of Beyond Compare beyondcompare3.args=$local $other $base $output /ro /lefttitle=local /centertitle=base /righttitle=other /automerge /reviewconflicts /solo beyondcompare3.regkey=Software\Scooter Software\Beyond Compare 3 beyondcompare3.regname=ExePath beyondcompare3.gui=True beyondcompare3.priority=-2 beyondcompare3.diffargs=/lro /lefttitle=$plabel1 /righttitle=$clabel /solo /expandall $parent $child ; Linux version of Beyond Compare bcompare.args=$local $other $base -mergeoutput=$output -ro -lefttitle=parent1 -centertitle=base -righttitle=parent2 -outputtitle=merged -automerge -reviewconflicts -solo bcompare.gui=True bcompare.priority=-1 bcompare.diffargs=-lro -lefttitle=$plabel1 -righttitle=$clabel -solo -expandall $parent $child ; OS X version of Beyond Compare bcomposx.executable = /Applications/Beyond Compare.app/Contents/MacOS/bcomp bcomposx.args=$local $other $base -mergeoutput=$output -ro -lefttitle=parent1 -centertitle=base -righttitle=parent2 -outputtitle=merged -automerge -reviewconflicts -solo bcomposx.gui=True bcomposx.priority=-1 bcomposx.diffargs=-lro -lefttitle=$plabel1 -righttitle=$clabel -solo -expandall $parent $child winmerge.args=/e /x /wl /ub /dl other /dr local $other $local $output winmerge.regkey=Software\Thingamahoochie\WinMerge winmerge.regkeyalt=Software\Wow6432Node\Thingamahoochie\WinMerge\ winmerge.regname=Executable winmerge.check=changed winmerge.gui=True winmerge.priority=-10 winmerge.diffargs=/r /e /x /ub /wl /dl $plabel1 /dr $clabel $parent $child araxis.regkey=SOFTWARE\Classes\TypeLib\{46799e0a-7bd1-4330-911c-9660bb964ea2}\7.0\HELPDIR araxis.regappend=\ConsoleCompare.exe araxis.priority=-2 araxis.args=/3 /a2 /wait /merge /title1:"Other" /title2:"Base" /title3:"Local :"$local $other $base $local $output araxis.checkconflict=True araxis.binary=True araxis.gui=True araxis.diffargs=/2 /wait /title1:$plabel1 /title2:$clabel $parent $child diffuse.priority=-3 diffuse.args=$local $base $other diffuse.gui=True diffuse.diffargs=$parent $child UltraCompare.regkey=Software\Microsoft\Windows\CurrentVersion\App Paths\UC.exe UltraCompare.regkeyalt=Software\Wow6432Node\Microsoft\Windows\CurrentVersion\App Paths\UC.exe UltraCompare.args = $base $local $other -title1 base -title3 other UltraCompare.priority = -2 UltraCompare.gui = True UltraCompare.binary = True UltraCompare.check = conflicts,changed UltraCompare.diffargs=$child $parent -title1 $clabel -title2 $plabel1