perf: clear vfs audit_cache before each run
When generating a stream clone, we spend a large amount of time auditing path.
Before this changes, the first run was warming the vfs cache for the other
runs, leading to a large runtime difference and a "faulty" reported timing for
the operation.
We now clear this important cache between run to get a more realistic timing.
Below are some example of median time change when clearing these cases. The
maximum time for a run did not changed significantly.
### data-env-vars.name = mozilla-central-2018-08-01-zstd-sparse-revlog
# benchmark.name = hg.perf.exchange.stream.generate
# bin-env-vars.hg.flavor = default
# bin-env-vars.hg.py-re2-module = default
# benchmark.variants.version = latest
no-clearing: 17.289905
cache-clearing: 21.587965 (+24.86%, +4.30)
## data-env-vars.name = mozilla-central-2024-03-22-zstd-sparse-revlog
no-clearing: 32.670748
cache-clearing: 40.467095 (+23.86%, +7.80)
## data-env-vars.name = mozilla-try-2019-02-18-zstd-sparse-revlog
no-clearing: 37.838858
cache-clearing: 46.072749 (+21.76%, +8.23)
## data-env-vars.name = mozilla-unified-2024-03-22-zstd-sparse-revlog
no-clearing: 32.969395
cache-clearing: 39.646209 (+20.25%, +6.68)
In addition, this significantly reduce the timing difference between the
performance command, from the perf extensions and a `real `hg bundle` call
producing a stream bundle. Some significant differences remain especially on
the "mozilla-try" repositories, but they are now smaller.
Note that some of that difference will actually not be
attributable to the stream generation (like maybe phases or branch map
computation).
Below are some benchmarks done on a currently draft changeset fixing some
unrelated slowness in `hg bundle` (34a78972af409d1ff37c29e60f6ca811ad1a457d)
### data-env-vars.name = mozilla-central-2018-08-01-zstd-sparse-revlog
# bin-env-vars.hg.flavor = default
# bin-env-vars.hg.py-re2-module = default
hg.perf.exchange.stream.generate: 21.587965
hg.command.bundle: 24.301799 (+12.57%, +2.71)
## data-env-vars.name = mozilla-central-2024-03-22-zstd-sparse-revlog
hg.perf.exchange.stream.generate: 40.467095
hg.command.bundle: 44.831317 (+10.78%, +4.36)
## data-env-vars.name = mozilla-unified-2024-03-22-zstd-sparse-revlog
hg.perf.exchange.stream.generate: 39.646209
hg.command.bundle: 45.395258 (+14.50%, +5.75)
## data-env-vars.name = mozilla-try-2019-02-18-zstd-sparse-revlog
hg.perf.exchange.stream.generate: 46.072749
hg.command.bundle: 55.882608 (+21.29%, +9.81)
## data-env-vars.name = mozilla-try-2023-03-22-zlib-general-delta
hg.perf.exchange.stream.generate: 334.716708
hg.command.bundle: 377.856767 (+12.89%, +43.14)
## data-env-vars.name = mozilla-try-2023-03-22-zstd-sparse-revlog
hg.perf.exchange.stream.generate: 302.972301
hg.command.bundle: 326.098755 (+7.63%, +23.13)
Test extension of unfinished states support.
$ mkdir chainify
$ cd chainify
$ cat >> chainify.py <<EOF
> from mercurial import cmdutil, error, extensions, exthelper, node, scmutil, state
> from hgext import rebase
>
> eh = exthelper.exthelper()
>
> extsetup = eh.finalextsetup
> cmdtable = eh.cmdtable
>
> # Rebase calls addunfinished in uisetup, so we have to call it in extsetup.
> # Ideally there'd by an 'extensions.afteruisetup()' just like
> # 'extensions.afterloaded()' to allow nesting multiple commands.
> @eh.extsetup
> def _extsetup(ui):
> state.addunfinished(
> b'chainify',
> b'chainify.state',
> continueflag=True,
> childopnames=[b'rebase'])
>
> def _node(repo, arg):
> return node.hex(scmutil.revsingle(repo, arg).node())
>
> @eh.command(
> b'chainify',
> [(b'r', b'revs', [], b'revs to chain', b'REV'),
> (b'', b'continue', False, b'continue op')],
> b'chainify [-r REV] +',
> inferrepo=True)
> def chainify(ui, repo, **opts):
> """Rebases r1, r2, r3, etc. into a chain."""
> with repo.wlock(), repo.lock():
> cmdstate = state.cmdstate(repo, b'chainify.state')
> if opts['continue']:
> if not cmdstate.exists():
> raise error.Abort(b'no chainify in progress')
> else:
> cmdutil.checkunfinished(repo)
> data = {
> b'tip': _node(repo, opts['revs'][0]),
> b'revs': b','.join(_node(repo, r) for r in opts['revs'][1:]),
> }
> cmdstate.save(1, data)
>
> data = cmdstate.read()
> while data[b'revs']:
> tip = data[b'tip']
> revs = data[b'revs'].split(b',')
> with state.delegating(repo, b'chainify', b'rebase'):
> ui.status(b'rebasing %s onto %s\n' % (revs[0][:12], tip[:12]))
> if state.ischildunfinished(repo, b'chainify', b'rebase'):
> rc = state.continuechild(ui, repo, b'chainify', b'rebase')
> else:
> rc = rebase.rebase(ui, repo, rev=[revs[0]], dest=tip)
> if rc and rc != 0:
> raise error.Abort(b'rebase failed (rc: %d)' % rc)
> data[b'tip'] = _node(repo, b'tip')
> data[b'revs'] = b','.join(revs[1:])
> cmdstate.save(1, data)
> cmdstate.delete()
> ui.status(b'done chainifying\n')
> EOF
$ chainifypath=`pwd`/chainify.py
$ echo '[extensions]' >> $HGRCPATH
$ echo "chainify = $chainifypath" >> $HGRCPATH
$ echo "rebase =" >> $HGRCPATH
$ cd $TESTTMP
$ hg init a
$ cd a
$ echo base > base.txt
$ hg commit -Aqm 'base commit'
$ echo foo > file1
$ hg commit -Aqm 'add file'
$ hg co -q ".^"
$ echo bar > file2
$ hg commit -Aqm 'add other file'
$ hg co -q ".^"
$ echo foo2 > file1
$ hg commit -Aqm 'add conflicting file'
$ hg co -q ".^"
$ hg log --graph --template '{rev} {files}'
o 3 file1
|
| o 2 file2
|/
| o 1 file1
|/
@ 0 base.txt
$ hg chainify -r 8430cfdf77c2 -r f8596309dff8 -r a858b338b3e9
rebasing f8596309dff8 onto 8430cfdf77c2
rebasing 2:f8596309dff8 "add other file"
saved backup bundle to $TESTTMP/* (glob)
rebasing a858b338b3e9 onto 83c722183a8e
rebasing 2:a858b338b3e9 "add conflicting file"
merging file1
warning: conflicts while merging file1! (edit, then use 'hg resolve --mark')
unresolved conflicts (see 'hg resolve', then 'hg chainify --continue')
[240]
$ hg status --config commands.status.verbose=True
M file1
? file1.orig
# The repository is in an unfinished *chainify* state.
# Unresolved merge conflicts:
#
# file1
#
# To mark files as resolved: hg resolve --mark FILE
# To continue: hg chainify --continue
# To abort: hg chainify --abort
$ echo foo3 > file1
$ hg resolve --mark file1
(no more unresolved files)
continue: hg chainify --continue
$ hg chainify --continue
rebasing a858b338b3e9 onto 83c722183a8e
rebasing 2:a858b338b3e9 "add conflicting file"
saved backup bundle to $TESTTMP/* (glob)
done chainifying
$ hg log --graph --template '{rev} {files}'
o 3 file1
|
o 2 file2
|
o 1 file1
|
@ 0 base.txt