manifest: persist the manifestfulltext cache
Reconstructing the manifest from the revlog takes time, so much so that there
already is a LRU cache to avoid having to load a manifest multiple times.
This patch persists that LRU cache in the .hg/cache directory, so we can re-use
this cache across hg commands. Commit benchmark (run on Macos 10.13 on a
2017-model Macbook Pro with Core i7 2.9GHz and flash drive), testing without
and with patch run 5 times, baseline is r2a227782e754:
* committing to an existing file, against the mozilla-central repository.
Baseline real time average 1.9692, with patch 1.3786.
A new debugcommand "hg debugmanifestfulltextcache" lets you inspect the cache,
clear it, or add specific manifest nodeids to it. When calling
repo.updatecaches(), the manifest(s) for the working copy parents are added to
the cache.
The hg perfmanifest command has an additional --clear-disk switch to clear this
cache when testing manifest loading performance.
Using this command to test performance on the firefox repository for revision
f947d902ed91, whose manifest has a delta chain length of 60540, we see:
$ hg perfmanifest f947d902ed91 --clear-disk
! wall 0.972253 comb 0.970000 user 0.850000 sys 0.120000 (best of 10)
$ hg debugmanifestfulltextcache -a `hg log --debug -r f947d902ed91 | grep manifest | cut -d: -f3`
Cache contains 1 manifest entries, in order of most to least recent:
id: 0294517df4aad07c70701db43bc7ff24c3ce7dbc, size 25.6 MB
Total cache data size 25.6 MB, on-disk 0 bytes
$ hg perfmanifest f947d902ed91
! wall 0.036748 comb 0.040000 user 0.020000 sys 0.020000 (best of 100)
Worst-case scenario: a manifest text loaded from a single delta; in the firefox
repository manifest node 9a1246ff762e is the chain base for the manifest
attached to revision f947d902ed91. Loading this from a full cache file is just
as fast as without the cache; the extra node ids ensure a big full cache:
$ for node in 9a1246ff762e 1a1922c14a3e 54a31d11a36a 0294517df4aa; do
> hgd debugmanifestfulltextcache -a $node > /dev/null
> done
$ hgd perfmanifest -m 9a1246ff762e
! wall 0.077513 comb 0.080000 user 0.030000 sys 0.050000 (best of 100)
$ hgd perfmanifest -m 9a1246ff762e --clear-disk
! wall 0.078547 comb 0.080000 user 0.070000 sys 0.010000 (best of 100)
test parents command
$ hg init repo
$ cd repo
no working directory
$ hg parents
$ echo a > a
$ echo b > b
$ hg ci -Amab -d '0 0'
adding a
adding b
$ echo a >> a
$ hg ci -Ama -d '1 0'
$ echo b >> b
$ hg ci -Amb -d '2 0'
$ echo c > c
$ hg ci -Amc -d '3 0'
adding c
$ hg up -C 1
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo d > c
$ hg ci -Amc2 -d '4 0'
adding c
created new head
$ hg up -C 3
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg parents
changeset: 3:02d851b7e549
user: test
date: Thu Jan 01 00:00:03 1970 +0000
summary: c
$ hg parents a
changeset: 1:d786049f033a
user: test
date: Thu Jan 01 00:00:01 1970 +0000
summary: a
hg parents c, single revision
$ hg parents c
changeset: 3:02d851b7e549
user: test
date: Thu Jan 01 00:00:03 1970 +0000
summary: c
$ hg parents -r 3 c
abort: 'c' not found in manifest!
[255]
$ hg parents -r 2
changeset: 1:d786049f033a
user: test
date: Thu Jan 01 00:00:01 1970 +0000
summary: a
$ hg parents -r 2 a
changeset: 1:d786049f033a
user: test
date: Thu Jan 01 00:00:01 1970 +0000
summary: a
$ hg parents -r 2 ../a
abort: ../a not under root '$TESTTMP/repo'
[255]
cd dir; hg parents -r 2 ../a
$ mkdir dir
$ cd dir
$ hg parents -r 2 ../a
changeset: 1:d786049f033a
user: test
date: Thu Jan 01 00:00:01 1970 +0000
summary: a
$ hg parents -r 2 path:a
changeset: 1:d786049f033a
user: test
date: Thu Jan 01 00:00:01 1970 +0000
summary: a
$ cd ..
$ hg parents -r 2 glob:a
abort: can only specify an explicit filename
[255]
merge working dir with 2 parents, hg parents c
$ HGMERGE=true hg merge
merging c
0 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg parents c
changeset: 3:02d851b7e549
user: test
date: Thu Jan 01 00:00:03 1970 +0000
summary: c
changeset: 4:48cee28d4b4e
tag: tip
parent: 1:d786049f033a
user: test
date: Thu Jan 01 00:00:04 1970 +0000
summary: c2
merge working dir with 1 parent, hg parents
$ hg up -C 2
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ HGMERGE=true hg merge -r 4
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg parents
changeset: 2:6cfac479f009
user: test
date: Thu Jan 01 00:00:02 1970 +0000
summary: b
changeset: 4:48cee28d4b4e
tag: tip
parent: 1:d786049f033a
user: test
date: Thu Jan 01 00:00:04 1970 +0000
summary: c2
merge working dir with 1 parent, hg parents c
$ hg parents c
changeset: 4:48cee28d4b4e
tag: tip
parent: 1:d786049f033a
user: test
date: Thu Jan 01 00:00:04 1970 +0000
summary: c2
$ cd ..