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)
Force revlog max inline value to be smaller than default
$ mkdir $TESTTMP/ext
$ cat << EOF > $TESTTMP/ext/small_inline.py
> from mercurial import revlog
> revlog._maxinline = 8
> EOF
$ cat << EOF >> $HGRCPATH
> [extensions]
> small_inline=$TESTTMP/ext/small_inline.py
> EOF
$ hg init repo
$ cd repo
Try on an empty repository
$ hg debug-revlog-stats
rev-count data-size inl type target
$ mkdir folder
$ touch a b folder/c folder/d
$ hg commit -Aqm 0
$ echo "text" > a
$ hg rm b
$ echo "longer string" > folder/d
$ hg commit -Aqm 1
Differences in data size observed with pure is due to different compression
algorithms
$ hg debug-revlog-stats
rev-count data-size inl type target
2 138 no changelog (no-pure !)
2 137 no changelog (pure !)
2 177 no manifest (no-pure !)
2 168 no manifest (pure !)
2 6 yes file a
1 0 yes file b
1 0 yes file folder/c
2 15 no file folder/d
Test 'changelog' command argument
$ hg debug-revlog-stats -c
rev-count data-size inl type target
2 138 no changelog (no-pure !)
2 137 no changelog (pure !)
Test 'manifest' command argument
$ hg debug-revlog-stats -m
rev-count data-size inl type target
2 177 no manifest (no-pure !)
2 168 no manifest (pure !)
Test 'file' command argument
$ hg debug-revlog-stats -f
rev-count data-size inl type target
2 6 yes file a
1 0 yes file b
1 0 yes file folder/c
2 15 no file folder/d
Test multiple command arguments
$ hg debug-revlog-stats -cm
rev-count data-size inl type target
2 138 no changelog (no-pure !)
2 137 no changelog (pure !)
2 177 no manifest (no-pure !)
2 168 no manifest (pure !)