mercurial/default.d/mergetools.rc

revlog: use existing file handle when reading during _addrevision

_addrevision() may need to read from revlogs as part of computing
deltas. Previously, we would flush existing file handles and open
a new, short-lived file handle to perform the reading.

If we have an existing file handle, it seems logical to reuse it
for reading instead of opening a new file handle. This patch
makes that the new behavior.

After this patch, revlog files are only reopened when adding
revisions if the revlog is switched from inline to non-inline.

On Linux when unbundling a bundle of the mozilla-central repo, this
patch has the following impact on system call counts:

Call     Before     After       Delta
write    827,639    673,390   -154,249
open     700,103    684,089    -16,014
read      74,489     74,489          0
fstat    493,924    461,896    -32,028
close    249,131    233,117    -16,014
stat     242,001    242,001          0
lstat     18,676     18,676          0
lseek     20,268     20,268          0
ioctl     14,652     13,173     -1,479
TOTAL  3,180,758  2,930,679   -250,079

It's worth noting that many of the open() calls fail due to missing
files. That's why there are many more open() calls than close().

Despite the significant system call reduction, this change does not
seem to have a significant performance impact on Linux.

On Windows 10 (not a VM, on a SSD), this patch appears to reduce
unbundle time for mozilla-central from ~960s to ~920s. This isn't
as significant as I was hoping. But a decrease it is nonetheless.
Still, Windows unbundle performance is still >2x slower than Linux.

Despite the lack of significant gains, fewer system calls is fewer
system calls. If nothing else, this will narrow the focus of potential
areas to optimize in the future.

# 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

; 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