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)
In this test, we want to test LFS bundle application on both LFS and non-LFS
repos.
To make it more interesting, the file revisions will contain hg filelog
metadata ('\1\n'). The bundle will have 1 file revision overlapping with the
destination repo.
# rev 1 2 3
# repo: yes yes no
# bundle: no (base) yes yes (deltabase: 2 if possible)
It is interesting because rev 2 could have been stored as LFS in the repo, and
non-LFS in the bundle; or vice-versa.
Init
$ cat >> $HGRCPATH << EOF
> [extensions]
> lfs=
> drawdag=$TESTDIR/drawdag.py
> [lfs]
> url=file:$TESTTMP/lfs-remote
> EOF
Helper functions
$ commitxy() {
> hg debugdrawdag "$@" <<'EOS'
> Y # Y/X=\1\nAAAA\nE\nF
> | # Y/Y=\1\nAAAA\nG\nH
> X # X/X=\1\nAAAA\nC\n
> # X/Y=\1\nAAAA\nD\n
> EOS
> }
$ commitz() {
> hg debugdrawdag "$@" <<'EOS'
> Z # Z/X=\1\nAAAA\nI\n
> | # Z/Y=\1\nAAAA\nJ\n
> | # Z/Z=\1\nZ
> Y
> EOS
> }
$ enablelfs() {
> cat >> .hg/hgrc <<EOF
> [lfs]
> track=all()
> EOF
> }
Generate bundles
$ for i in normal lfs; do
> NAME=src-$i
> hg init $TESTTMP/$NAME
> cd $TESTTMP/$NAME
> [ $i = lfs ] && enablelfs
> commitxy
> commitz
> hg bundle -q --base X -r Y+Z $TESTTMP/$NAME.bundle
> SRCNAMES="$SRCNAMES $NAME"
> done
Prepare destination repos
$ for i in normal lfs; do
> NAME=dst-$i
> hg init $TESTTMP/$NAME
> cd $TESTTMP/$NAME
> [ $i = lfs ] && enablelfs
> commitxy
> DSTNAMES="$DSTNAMES $NAME"
> done
Apply bundles
$ for i in $SRCNAMES; do
> for j in $DSTNAMES; do
> echo ---- Applying $i.bundle to $j ----
> cp -R $TESTTMP/$j $TESTTMP/tmp-$i-$j
> cd $TESTTMP/tmp-$i-$j
> if hg unbundle $TESTTMP/$i.bundle -q 2>/dev/null; then
> hg verify -q && echo OK
> else
> echo CRASHED
> fi
> done
> done
---- Applying src-normal.bundle to dst-normal ----
OK
---- Applying src-normal.bundle to dst-lfs ----
OK
---- Applying src-lfs.bundle to dst-normal ----
OK
---- Applying src-lfs.bundle to dst-lfs ----
OK
Hint if the cache location cannot be inferred from the environment
#if windows
$ unset LOCALAPPDATA
$ unset APPDATA
$ HGRCPATH= hg config lfs --source
abort: unknown lfs usercache location
(define LOCALAPPDATA or APPDATA in the environment, or set lfs.usercache)
[255]
#endif
#if osx
$ unset HOME
$ HGRCPATH= hg config lfs --source
abort: unknown lfs usercache location
(define HOME in the environment, or set lfs.usercache)
[255]
#endif
#if no-windows no-osx
$ unset XDG_CACHE_HOME
$ unset HOME
$ HGRCPATH= hg config lfs --source
abort: unknown lfs usercache location
(define XDG_CACHE_HOME or HOME in the environment, or set lfs.usercache)
[255]
#endif