util: lower water mark when removing nodes after cost limit reached
See the inline comment for the reasoning here. This is a pretty
common strategy for garbage collectors, other cache-like primtives.
The performance impact is substantial:
$ hg perflrucachedict --size 4 --gets 1000000 --sets 1000000 --mixed 1000000 --costlimit 100
! inserts w/ cost limit
! wall 1.659181 comb 1.650000 user 1.650000 sys 0.000000 (best of 7)
! wall 1.722122 comb 1.720000 user 1.720000 sys 0.000000 (best of 6)
! mixed w/ cost limit
! wall 1.139955 comb 1.140000 user 1.140000 sys 0.000000 (best of 9)
! wall 1.182513 comb 1.180000 user 1.180000 sys 0.000000 (best of 9)
$ hg perflrucachedict --size 1000 --gets 1000000 --sets 1000000 --mixed 1000000 --costlimit 10000
! inserts
! wall 0.679546 comb 0.680000 user 0.680000 sys 0.000000 (best of 15)
! sets
! wall 0.825147 comb 0.830000 user 0.830000 sys 0.000000 (best of 13)
! inserts w/ cost limit
! wall 25.105273 comb 25.080000 user 25.080000 sys 0.000000 (best of 3)
! wall 1.724397 comb 1.720000 user 1.720000 sys 0.000000 (best of 6)
! mixed
! wall 0.807096 comb 0.810000 user 0.810000 sys 0.000000 (best of 13)
! mixed w/ cost limit
! wall 12.104470 comb 12.070000 user 12.070000 sys 0.000000 (best of 3)
! wall 1.190563 comb 1.190000 user 1.190000 sys 0.000000 (best of 9)
$ hg perflrucachedict --size 1000 --gets 1000000 --sets 1000000 --mixed 1000000 --costlimit 10000 --mixedgetfreq 90
! inserts
! wall 0.711177 comb 0.710000 user 0.710000 sys 0.000000 (best of 14)
! sets
! wall 0.846992 comb 0.850000 user 0.850000 sys 0.000000 (best of 12)
! inserts w/ cost limit
! wall 25.963028 comb 25.960000 user 25.960000 sys 0.000000 (best of 3)
! wall 2.184311 comb 2.180000 user 2.180000 sys 0.000000 (best of 5)
! mixed
! wall 0.728256 comb 0.730000 user 0.730000 sys 0.000000 (best of 14)
! mixed w/ cost limit
! wall 3.174256 comb 3.170000 user 3.170000 sys 0.000000 (best of 4)
! wall 0.773186 comb 0.770000 user 0.770000 sys 0.000000 (best of 13)
$ hg perflrucachedict --size 100000 --gets 1000000 --sets 1000000 --mixed 1000000 --mixedgetfreq 90 --costlimit 5000000
! gets
! wall 1.191368 comb 1.190000 user 1.190000 sys 0.000000 (best of 9)
! wall 1.195304 comb 1.190000 user 1.190000 sys 0.000000 (best of 9)
! inserts
! wall 0.950995 comb 0.950000 user 0.950000 sys 0.000000 (best of 11)
! inserts w/ cost limit
! wall 1.589732 comb 1.590000 user 1.590000 sys 0.000000 (best of 7)
! sets
! wall 1.094941 comb 1.100000 user 1.090000 sys 0.010000 (best of 9)
! mixed
! wall 0.936420 comb 0.940000 user 0.930000 sys 0.010000 (best of 10)
! mixed w/ cost limit
! wall 0.882780 comb 0.870000 user 0.870000 sys 0.000000 (best of 11)
This puts us ~2x slower than caches without cost accounting. And for
read-heavy workloads (the prime use cases for caches), performance is
nearly identical.
In the worst case (pure write workloads with cost accounting enabled),
we're looking at ~1.5us per insert on large caches. That seems "fast
enough."
Differential Revision: https://phab.mercurial-scm.org/D4505
mock bugzilla driver for testing template output:
$ cat <<EOF > bzmock.py
> from __future__ import absolute_import
> from mercurial import extensions
> from mercurial import registrar
>
> configtable = {}
> configitem = registrar.configitem(configtable)
>
> configitem(b'bugzilla', b'mocklog',
> default=None,
> )
> def extsetup(ui):
> bugzilla = extensions.find(b'bugzilla')
> class bzmock(bugzilla.bzaccess):
> def __init__(self, ui):
> super(bzmock, self).__init__(ui)
> self._logfile = ui.config(b'bugzilla', b'mocklog')
> def updatebug(self, bugid, newstate, text, committer):
> with open(self._logfile, 'a') as f:
> f.write('update bugid=%r, newstate=%r, committer=%r\n'
> % (bugid, newstate, committer))
> f.write('----\n' + text + '\n----\n')
> def notify(self, bugs, committer):
> with open(self._logfile, 'a') as f:
> f.write('notify bugs=%r, committer=%r\n'
> % (bugs, committer))
> bugzilla.bugzilla._versions[b'mock'] = bzmock
> EOF
set up mock repository:
$ hg init mockremote
$ cat <<EOF > mockremote/.hg/hgrc
> [extensions]
> bugzilla =
> bzmock = $TESTTMP/bzmock.py
>
> [bugzilla]
> version = mock
> mocklog = $TESTTMP/bzmock.log
>
> [hooks]
> incoming.bugzilla = python:hgext.bugzilla.hook
>
> [web]
> baseurl=http://example.org/hg
>
> %include $TESTTMP/bzstyle.hgrc
> EOF
$ hg clone -q mockremote mocklocal
push with default template:
$ echo '[bugzilla]' > bzstyle.hgrc
$ echo foo > mocklocal/foo
$ hg ci -R mocklocal -Aqm 'Fixes bug 123'
$ hg -R mocklocal push -q
$ cat bzmock.log && rm bzmock.log
update bugid=123, newstate={}, committer='test'
----
changeset 7875a8342c6f in repo $TESTTMP/mockremote refers to bug 123.
details:
Fixes bug 123
----
notify bugs={123: {}}, committer='test'
push with style:
$ cat <<EOF > bzstyle.map
> changeset = "{node|short} refers to bug {bug}."
> EOF
$ echo "style = $TESTTMP/bzstyle.map" >> bzstyle.hgrc
$ echo foo >> mocklocal/foo
$ hg ci -R mocklocal -qm 'Fixes bug 456'
$ hg -R mocklocal push -q
$ cat bzmock.log && rm bzmock.log
update bugid=456, newstate={}, committer='test'
----
2808b172464b refers to bug 456.
----
notify bugs={456: {}}, committer='test'
push with template (overrides style):
$ cat <<EOF >> bzstyle.hgrc
> template = Changeset {node|short} in {root|basename}.
> {hgweb}/rev/{node|short}\n
> {desc}
> EOF
$ echo foo >> mocklocal/foo
$ hg ci -R mocklocal -qm 'Fixes bug 789'
$ hg -R mocklocal push -q
$ cat bzmock.log && rm bzmock.log
update bugid=789, newstate={}, committer='test'
----
Changeset a770f3e409f2 in mockremote.
http://example.org/hg/rev/a770f3e409f2
Fixes bug 789
----
notify bugs={789: {}}, committer='test'