bundle2: implement consume() API on unbundlepart
We want bundle parts to not be seekable by default. That means
eliminating the generic seek() method.
A common pattern in bundle2.py is to seek to the end of the part
data. This is mainly used by the part iteration code to ensure
the underlying stream is advanced to the next bundle part.
In this commit, we establish a dedicated API for consuming a
bundle2 part data. We switch users of seek() to it.
The old implementation of seek(0, os.SEEK_END) would effectively
call self.read(). The new implementation calls self.read(32768)
in a loop. The old implementation would therefore assemble a
buffer to hold all remaining data being seeked over. For seeking
over large bundle parts, this would involve a large allocation and
a lot of overhead to collect intermediate data! This overhead can
be seen in the results for `hg perfbundleread`:
! bundle2 iterparts()
! wall 10.891305 comb 10.820000 user 7.990000 sys 2.830000 (best of 3)
! wall 8.070791 comb 8.060000 user 7.180000 sys 0.880000 (best of 3)
! bundle2 part seek()
! wall 12.991478 comb 10.390000 user 7.720000 sys 2.670000 (best of 3)
! wall 10.370142 comb 10.350000 user 7.430000 sys 2.920000 (best of 3)
Of course, skipping over large payload data isn't likely very common.
So I doubt the performance wins will be observed in the wild.
Differential Revision: https://phab.mercurial-scm.org/D1388
#require test-repo
Set vars:
$ . "$TESTDIR/helpers-testrepo.sh"
$ CONTRIBDIR="$TESTDIR/../contrib"
Prepare repo:
$ hg init
$ echo this is file a > a
$ hg add a
$ hg commit -m first
$ echo adding to file a >> a
$ hg commit -m second
$ echo adding more to file a >> a
$ hg commit -m third
$ hg up -r 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo merge-this >> a
$ hg commit -m merge-able
created new head
$ hg up -r 2
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
perfstatus
$ cat >> $HGRCPATH << EOF
> [extensions]
> perfstatusext=$CONTRIBDIR/perf.py
> [perf]
> presleep=0
> stub=on
> parentscount=1
> EOF
$ hg help perfstatusext
perfstatusext extension - helper extension to measure performance
list of commands:
perfaddremove
(no help text available)
perfancestors
(no help text available)
perfancestorset
(no help text available)
perfannotate (no help text available)
perfbdiff benchmark a bdiff between revisions
perfbookmarks
benchmark parsing bookmarks from disk to memory
perfbranchmap
benchmark the update of a branchmap
perfbundleread
Benchmark reading of bundle files.
perfcca (no help text available)
perfchangegroupchangelog
Benchmark producing a changelog group for a changegroup.
perfchangeset
(no help text available)
perfctxfiles (no help text available)
perfdiffwd Profile diff of working directory changes
perfdirfoldmap
(no help text available)
perfdirs (no help text available)
perfdirstate (no help text available)
perfdirstatedirs
(no help text available)
perfdirstatefoldmap
(no help text available)
perfdirstatewrite
(no help text available)
perffncacheencode
(no help text available)
perffncacheload
(no help text available)
perffncachewrite
(no help text available)
perfheads (no help text available)
perfindex (no help text available)
perfloadmarkers
benchmark the time to parse the on-disk markers for a repo
perflog (no help text available)
perflookup (no help text available)
perflrucachedict
(no help text available)
perfmanifest (no help text available)
perfmergecalculate
(no help text available)
perfmoonwalk benchmark walking the changelog backwards
perfnodelookup
(no help text available)
perfparents (no help text available)
perfpathcopies
(no help text available)
perfphases benchmark phasesets computation
perfrawfiles (no help text available)
perfrevlogchunks
Benchmark operations on revlog chunks.
perfrevlogindex
Benchmark operations against a revlog index.
perfrevlogrevision
Benchmark obtaining a revlog revision.
perfrevlogrevisions
Benchmark reading a series of revisions from a revlog.
perfrevrange (no help text available)
perfrevset benchmark the execution time of a revset
perfstartup (no help text available)
perfstatus (no help text available)
perftags (no help text available)
perftemplating
(no help text available)
perfvolatilesets
benchmark the computation of various volatile set
perfwalk (no help text available)
perfwrite microbenchmark ui.write
(use 'hg help -v perfstatusext' to show built-in aliases and global options)
$ hg perfaddremove
$ hg perfancestors
$ hg perfancestorset 2
$ hg perfannotate a
$ hg perfbdiff -c 1
$ hg perfbdiff --alldata 1
$ hg perfbookmarks
$ hg perfbranchmap
$ hg perfcca
$ hg perfchangegroupchangelog
$ hg perfchangeset 2
$ hg perfctxfiles 2
$ hg perfdiffwd
$ hg perfdirfoldmap
$ hg perfdirs
$ hg perfdirstate
$ hg perfdirstatedirs
$ hg perfdirstatefoldmap
$ hg perfdirstatewrite
$ hg perffncacheencode
$ hg perffncacheload
$ hg perffncachewrite
$ hg perfheads
$ hg perfindex
$ hg perfloadmarkers
$ hg perflog
$ hg perflookup 2
$ hg perflrucache
$ hg perfmanifest 2
$ hg perfmergecalculate -r 3
$ hg perfmoonwalk
$ hg perfnodelookup 2
$ hg perfpathcopies 1 2
$ hg perfrawfiles 2
$ hg perfrevlogindex -c
$ hg perfrevlogrevisions .hg/store/data/a.i
$ hg perfrevlogrevision -m 0
$ hg perfrevlogchunks -c
$ hg perfrevrange
$ hg perfrevset 'all()'
$ hg perfstartup
$ hg perfstatus
$ hg perftags
$ hg perftemplating
$ hg perfvolatilesets
$ hg perfwalk
$ hg perfparents
Check perf.py for historical portability
$ cd "$TESTDIR/.."
$ (testrepohg files -r 1.2 glob:mercurial/*.c glob:mercurial/*.py;
> testrepohg files -r tip glob:mercurial/*.c glob:mercurial/*.py) |
> "$TESTDIR"/check-perf-code.py contrib/perf.py
contrib/perf.py:498:
> from mercurial import (
import newer module separately in try clause for early Mercurial
[1]