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)
# A B
#
# 3 4 3
# |\/| |\
# |/\| | \
# 1 2 1 2
# \ / \ /
# 0 0
#
# if the result of the merge of 1 and 2
# is the same in 3 and 4, no new manifest
# will be created and the manifest group
# will be empty during the pull
#
# (plus we test a failure where outgoing
# wrongly reported the number of csets)
$ hg init a
$ cd a
$ touch init
$ hg ci -A -m 0
adding init
$ touch x y
$ hg ci -A -m 1
adding x
adding y
$ hg update 0
0 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ touch x y
$ hg ci -A -m 2
adding x
adding y
created new head
$ hg merge 1
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -A -m m1
$ hg update -C 1
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg merge 2
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -A -m m2
created new head
$ cd ..
$ hg clone -r 3 a b
adding changesets
adding manifests
adding file changes
added 4 changesets with 3 changes to 3 files
new changesets 5fcb73622933:d15a0c284984
updating to branch default
3 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg clone -r 4 a c
adding changesets
adding manifests
adding file changes
added 4 changesets with 3 changes to 3 files
new changesets 5fcb73622933:1ec3c74fc0e0
updating to branch default
3 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg -R a outgoing b
comparing with b
searching for changes
changeset: 4:1ec3c74fc0e0
tag: tip
parent: 1:79f9e10cd04e
parent: 2:8e1bb01c1a24
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: m2
$ hg -R a outgoing c
comparing with c
searching for changes
changeset: 3:d15a0c284984
parent: 2:8e1bb01c1a24
parent: 1:79f9e10cd04e
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: m1
$ hg -R b outgoing c
comparing with c
searching for changes
changeset: 3:d15a0c284984
tag: tip
parent: 2:8e1bb01c1a24
parent: 1:79f9e10cd04e
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: m1
$ hg -R c outgoing b
comparing with b
searching for changes
changeset: 3:1ec3c74fc0e0
tag: tip
parent: 1:79f9e10cd04e
parent: 2:8e1bb01c1a24
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: m2
$ hg -R b pull a
pulling from a
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 0 files (+1 heads)
new changesets 1ec3c74fc0e0
(run 'hg heads' to see heads, 'hg merge' to merge)
$ hg -R c pull a
pulling from a
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 0 files (+1 heads)
new changesets d15a0c284984
(run 'hg heads' to see heads, 'hg merge' to merge)