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)
This test makes sure that we don't mark a file as merged with its ancestor
when we do a merge.
$ cat <<EOF > merge
> import sys, os
> print("merging for", os.path.basename(sys.argv[1]))
> EOF
$ HGMERGE="\"$PYTHON\" ../merge"; export HGMERGE
Creating base:
$ hg init a
$ cd a
$ echo 1 > foo
$ echo 1 > bar
$ echo 1 > baz
$ echo 1 > quux
$ hg add foo bar baz quux
$ hg commit -m "base"
$ cd ..
$ hg clone a b
updating to branch default
4 files updated, 0 files merged, 0 files removed, 0 files unresolved
Creating branch a:
$ cd a
$ echo 2a > foo
$ echo 2a > bar
$ hg commit -m "branch a"
Creating branch b:
$ cd ..
$ cd b
$ echo 2b > foo
$ echo 2b > baz
$ hg commit -m "branch b"
We shouldn't have anything but n state here:
$ hg debugstate --no-dates | grep -v "^n"
[1]
Merging:
$ hg pull ../a
pulling from ../a
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 2 changes to 2 files (+1 heads)
new changesets bdd988058d16
(run 'hg heads' to see heads, 'hg merge' to merge)
$ hg merge -v
resolving manifests
getting bar
merging foo
merging for foo
1 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ echo 2m > foo
$ echo 2b > baz
$ echo new > quux
$ hg ci -m "merge"
main: we should have a merge here:
$ hg debugindex --changelog
rev linkrev nodeid p1-nodeid p2-nodeid
0 0 cdca01651b96 000000000000 000000000000
1 1 f6718a9cb7f3 cdca01651b96 000000000000
2 2 bdd988058d16 cdca01651b96 000000000000
3 3 d8a521142a3c f6718a9cb7f3 bdd988058d16
log should show foo and quux changed:
$ hg log -v -r tip
changeset: 3:d8a521142a3c
tag: tip
parent: 1:f6718a9cb7f3
parent: 2:bdd988058d16
user: test
date: Thu Jan 01 00:00:00 1970 +0000
files: foo quux
description:
merge
foo: we should have a merge here:
$ hg debugindex foo
rev linkrev nodeid p1-nodeid p2-nodeid
0 0 b8e02f643373 000000000000 000000000000
1 1 2ffeddde1b65 b8e02f643373 000000000000
2 2 33d1fb69067a b8e02f643373 000000000000
3 3 aa27919ee430 2ffeddde1b65 33d1fb69067a
bar: we should not have a merge here:
$ hg debugindex bar
rev linkrev nodeid p1-nodeid p2-nodeid
0 0 b8e02f643373 000000000000 000000000000
1 2 33d1fb69067a b8e02f643373 000000000000
baz: we should not have a merge here:
$ hg debugindex baz
rev linkrev nodeid p1-nodeid p2-nodeid
0 0 b8e02f643373 000000000000 000000000000
1 1 2ffeddde1b65 b8e02f643373 000000000000
quux: we should not have a merge here:
$ hg debugindex quux
rev linkrev nodeid p1-nodeid p2-nodeid
0 0 b8e02f643373 000000000000 000000000000
1 3 6128c0f33108 b8e02f643373 000000000000
Manifest entries should match tips of all files:
$ hg manifest --debug
33d1fb69067a0139622a3fa3b7ba1cdb1367972e 644 bar
2ffeddde1b65b4827f6746174a145474129fa2ce 644 baz
aa27919ee4303cfd575e1fb932dd64d75aa08be4 644 foo
6128c0f33108e8cfbb4e0824d13ae48b466d7280 644 quux
Everything should be clean now:
$ hg status
$ hg verify -q
$ cd ..