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
This tests if hgweb and hgwebdir still work if the REQUEST_URI variable is
no longer passed with the request. Instead, SCRIPT_NAME and PATH_INFO
should be used from d74fc8dec2b4 onward to route the request.
$ hg init repo
$ cd repo
$ echo foo > bar
$ hg add bar
$ hg commit -m "test"
$ hg tip
changeset: 0:61c9426e69fe
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: test
$ cat > request.py <<EOF
> from __future__ import absolute_import
> import os
> import sys
> from mercurial.hgweb import (
> hgweb,
> hgwebdir,
> )
> from mercurial import (
> util,
> )
> stringio = util.stringio
>
> errors = stringio()
> input = stringio()
>
> def startrsp(status, headers):
> print('---- STATUS')
> print(status)
> print('---- HEADERS')
> print([i for i in headers if i[0] != 'ETag'])
> print('---- DATA')
> return output.write
>
> env = {
> 'wsgi.version': (1, 0),
> 'wsgi.url_scheme': 'http',
> 'wsgi.errors': errors,
> 'wsgi.input': input,
> 'wsgi.multithread': False,
> 'wsgi.multiprocess': False,
> 'wsgi.run_once': False,
> 'REQUEST_METHOD': 'GET',
> 'PATH_INFO': '/',
> 'SCRIPT_NAME': '',
> 'SERVER_NAME': '$LOCALIP',
> 'SERVER_PORT': os.environ['HGPORT'],
> 'SERVER_PROTOCOL': 'HTTP/1.0'
> }
>
> def process(app):
> content = app(env, startrsp)
> sys.stdout.write(output.getvalue())
> sys.stdout.write(''.join(content))
> getattr(content, 'close', lambda : None)()
> print('---- ERRORS')
> print(errors.getvalue())
>
> output = stringio()
> env['QUERY_STRING'] = 'style=atom'
> process(hgweb('.', name='repo'))
>
> output = stringio()
> env['QUERY_STRING'] = 'style=raw'
> process(hgwebdir({'repo': '.'}))
> EOF
$ $PYTHON request.py
---- STATUS
200 Script output follows
---- HEADERS
[('Content-Type', 'application/atom+xml; charset=ascii')]
---- DATA
<?xml version="1.0" encoding="ascii"?>
<feed xmlns="http://www.w3.org/2005/Atom">
<!-- Changelog -->
<id>http://$LOCALIP:$HGPORT/</id> (glob)
<link rel="self" href="http://$LOCALIP:$HGPORT/atom-log"/> (glob)
<link rel="alternate" href="http://$LOCALIP:$HGPORT/"/> (glob)
<title>repo Changelog</title>
<updated>1970-01-01T00:00:00+00:00</updated>
<entry>
<title>[default] test</title>
<id>http://$LOCALIP:$HGPORT/#changeset-61c9426e69fef294feed5e2bbfc97d39944a5b1c</id> (glob)
<link href="http://$LOCALIP:$HGPORT/rev/61c9426e69fe"/> (glob)
<author>
<name>test</name>
<email>test</email>
</author>
<updated>1970-01-01T00:00:00+00:00</updated>
<published>1970-01-01T00:00:00+00:00</published>
<content type="xhtml">
<table xmlns="http://www.w3.org/1999/xhtml">
<tr>
<th style="text-align:left;">changeset</th>
<td>61c9426e69fe</td>
</tr>
<tr>
<th style="text-align:left;">branch</th>
<td>default</td>
</tr>
<tr>
<th style="text-align:left;">bookmark</th>
<td></td>
</tr>
<tr>
<th style="text-align:left;">tag</th>
<td>tip</td>
</tr>
<tr>
<th style="text-align:left;">user</th>
<td>test</td>
</tr>
<tr>
<th style="text-align:left;vertical-align:top;">description</th>
<td>test</td>
</tr>
<tr>
<th style="text-align:left;vertical-align:top;">files</th>
<td>bar<br /></td>
</tr>
</table>
</content>
</entry>
</feed>
---- ERRORS
---- STATUS
200 Script output follows
---- HEADERS
[('Content-Type', 'text/plain; charset=ascii')]
---- DATA
/repo/
---- ERRORS
$ cd ..