Mercurial > hg
view tests/test-http-api.t @ 38732:be4984261611
merge: mark file gets as not thread safe (issue5933)
In default installs, this has the effect of disabling the thread-based
worker on Windows when manifesting files in the working directory. My
measurements have shown that with revlog-based repositories, Mercurial
spends a lot of CPU time in revlog code resolving file data. This ends
up incurring a lot of context switching across threads and slows down
`hg update` operations when going from an empty working directory to
the tip of the repo.
On mozilla-unified (246,351 files) on an i7-6700K (4+4 CPUs):
before: 487s wall
after: 360s wall (equivalent to worker.enabled=false)
cpus=2: 379s wall
Even with only 2 threads, the thread pool is still slower.
The introduction of the thread-based worker (02b36e860e0b) states that
it resulted in a "~50%" speedup for `hg sparse --enable-profile` and
`hg sparse --disable-profile`. This disagrees with my measurement
above. I theorize a few reasons for this:
1) Removal of files from the working directory is I/O - not CPU - bound
and should benefit from a thread pool (unless I/O is insanely fast
and the GIL release is near instantaneous). So tests like `hg sparse
--enable-profile` may exercise deletion throughput and aren't good
benchmarks for worker tasks that are CPU heavy.
2) The patch was authored by someone at Facebook. The results were
likely measured against a repository using remotefilelog. And I
believe that revision retrieval during working directory updates with
remotefilelog will often use a remote store, thus being I/O and not
CPU bound. This probably resulted in an overstated performance gain.
Since there appears to be a need to enable the thread-based worker with
some stores, I've made the flagging of file gets as thread safe
configurable. I've made it experimental because I don't want to formalize
a boolean flag for this option and because this attribute is best
captured against the store implementation. But we don't have a proper
store API for this yet. I'd rather cross this bridge later.
It is possible there are revlog-based repositories that do benefit from
a thread-based worker. I didn't do very comprehensive testing. If there
are, we may want to devise a more proper algorithm for whether to use
the thread-based worker, including possibly config options to limit the
number of threads to use. But until I see evidence that justifies
complexity, simplicity wins.
Differential Revision: https://phab.mercurial-scm.org/D3963
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Wed, 18 Jul 2018 09:49:34 -0700 |
parents | 538e850ae737 |
children | d059cb669632 |
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#require no-chg $ send() { > hg --verbose debugwireproto --peer raw http://$LOCALIP:$HGPORT/ > } $ hg init server $ hg -R server serve -p $HGPORT -d --pid-file hg.pid $ cat hg.pid > $DAEMON_PIDS Request to /api fails unless web.apiserver is enabled $ get-with-headers.py $LOCALIP:$HGPORT api 400 no such method: api <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-US"> <head> <link rel="icon" href="/static/hgicon.png" type="image/png" /> <meta name="robots" content="index, nofollow" /> <link rel="stylesheet" href="/static/style-paper.css" type="text/css" /> <script type="text/javascript" src="/static/mercurial.js"></script> <title>$TESTTMP/server: error</title> </head> <body> <div class="container"> <div class="menu"> <div class="logo"> <a href="https://mercurial-scm.org/"> <img src="/static/hglogo.png" width=75 height=90 border=0 alt="mercurial" /></a> </div> <ul> <li><a href="/shortlog">log</a></li> <li><a href="/graph">graph</a></li> <li><a href="/tags">tags</a></li> <li><a href="/bookmarks">bookmarks</a></li> <li><a href="/branches">branches</a></li> </ul> <ul> <li><a href="/help">help</a></li> </ul> </div> <div class="main"> <h2 class="breadcrumb"><a href="/">Mercurial</a> </h2> <h3>error</h3> <form class="search" action="/log"> <p><input name="rev" id="search1" type="text" size="30" value="" /></p> <div id="hint">Find changesets by keywords (author, files, the commit message), revision number or hash, or <a href="/help/revsets">revset expression</a>.</div> </form> <div class="description"> <p> An error occurred while processing your request: </p> <p> no such method: api </p> </div> </div> </div> </body> </html> [1] $ get-with-headers.py $LOCALIP:$HGPORT api/ 400 no such method: api <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-US"> <head> <link rel="icon" href="/static/hgicon.png" type="image/png" /> <meta name="robots" content="index, nofollow" /> <link rel="stylesheet" href="/static/style-paper.css" type="text/css" /> <script type="text/javascript" src="/static/mercurial.js"></script> <title>$TESTTMP/server: error</title> </head> <body> <div class="container"> <div class="menu"> <div class="logo"> <a href="https://mercurial-scm.org/"> <img src="/static/hglogo.png" width=75 height=90 border=0 alt="mercurial" /></a> </div> <ul> <li><a href="/shortlog">log</a></li> <li><a href="/graph">graph</a></li> <li><a href="/tags">tags</a></li> <li><a href="/bookmarks">bookmarks</a></li> <li><a href="/branches">branches</a></li> </ul> <ul> <li><a href="/help">help</a></li> </ul> </div> <div class="main"> <h2 class="breadcrumb"><a href="/">Mercurial</a> </h2> <h3>error</h3> <form class="search" action="/log"> <p><input name="rev" id="search1" type="text" size="30" value="" /></p> <div id="hint">Find changesets by keywords (author, files, the commit message), revision number or hash, or <a href="/help/revsets">revset expression</a>.</div> </form> <div class="description"> <p> An error occurred while processing your request: </p> <p> no such method: api </p> </div> </div> </div> </body> </html> [1] Restart server with support for API server $ killdaemons.py $ cat > server/.hg/hgrc << EOF > [experimental] > web.apiserver = true > EOF $ hg -R server serve -p $HGPORT -d --pid-file hg.pid $ cat hg.pid > $DAEMON_PIDS /api lists available APIs (empty since none are available by default) $ send << EOF > httprequest GET api > user-agent: test > EOF using raw connection to peer s> GET /api HTTP/1.1\r\n s> Accept-Encoding: identity\r\n s> user-agent: test\r\n s> host: $LOCALIP:$HGPORT\r\n (glob) s> \r\n s> makefile('rb', None) s> HTTP/1.1 200 OK\r\n s> Server: testing stub value\r\n s> Date: $HTTP_DATE$\r\n s> Content-Type: text/plain\r\n s> Content-Length: 100\r\n s> \r\n s> APIs can be accessed at /api/<name>, where <name> can be one of the following:\n s> \n s> (no available APIs)\n $ send << EOF > httprequest GET api/ > user-agent: test > EOF using raw connection to peer s> GET /api/ HTTP/1.1\r\n s> Accept-Encoding: identity\r\n s> user-agent: test\r\n s> host: $LOCALIP:$HGPORT\r\n (glob) s> \r\n s> makefile('rb', None) s> HTTP/1.1 200 OK\r\n s> Server: testing stub value\r\n s> Date: $HTTP_DATE$\r\n s> Content-Type: text/plain\r\n s> Content-Length: 100\r\n s> \r\n s> APIs can be accessed at /api/<name>, where <name> can be one of the following:\n s> \n s> (no available APIs)\n Accessing an unknown API yields a 404 $ send << EOF > httprequest GET api/unknown > user-agent: test > EOF using raw connection to peer s> GET /api/unknown HTTP/1.1\r\n s> Accept-Encoding: identity\r\n s> user-agent: test\r\n s> host: $LOCALIP:$HGPORT\r\n (glob) s> \r\n s> makefile('rb', None) s> HTTP/1.1 404 Not Found\r\n s> Server: testing stub value\r\n s> Date: $HTTP_DATE$\r\n s> Content-Type: text/plain\r\n s> Content-Length: 33\r\n s> \r\n s> Unknown API: unknown\n s> Known APIs: Accessing a known but not enabled API yields a different error $ send << EOF > httprequest GET api/exp-http-v2-0001 > user-agent: test > EOF using raw connection to peer s> GET /api/exp-http-v2-0001 HTTP/1.1\r\n s> Accept-Encoding: identity\r\n s> user-agent: test\r\n s> host: $LOCALIP:$HGPORT\r\n (glob) s> \r\n s> makefile('rb', None) s> HTTP/1.1 404 Not Found\r\n s> Server: testing stub value\r\n s> Date: $HTTP_DATE$\r\n s> Content-Type: text/plain\r\n s> Content-Length: 33\r\n s> \r\n s> API exp-http-v2-0001 not enabled\n Restart server with support for HTTP v2 API $ killdaemons.py $ cat > server/.hg/hgrc << EOF > [experimental] > web.apiserver = true > web.api.http-v2 = true > EOF $ hg -R server serve -p $HGPORT -d --pid-file hg.pid $ cat hg.pid > $DAEMON_PIDS /api lists the HTTP v2 protocol as available $ send << EOF > httprequest GET api > user-agent: test > EOF using raw connection to peer s> GET /api HTTP/1.1\r\n s> Accept-Encoding: identity\r\n s> user-agent: test\r\n s> host: $LOCALIP:$HGPORT\r\n (glob) s> \r\n s> makefile('rb', None) s> HTTP/1.1 200 OK\r\n s> Server: testing stub value\r\n s> Date: $HTTP_DATE$\r\n s> Content-Type: text/plain\r\n s> Content-Length: 96\r\n s> \r\n s> APIs can be accessed at /api/<name>, where <name> can be one of the following:\n s> \n s> exp-http-v2-0001 $ send << EOF > httprequest GET api/ > user-agent: test > EOF using raw connection to peer s> GET /api/ HTTP/1.1\r\n s> Accept-Encoding: identity\r\n s> user-agent: test\r\n s> host: $LOCALIP:$HGPORT\r\n (glob) s> \r\n s> makefile('rb', None) s> HTTP/1.1 200 OK\r\n s> Server: testing stub value\r\n s> Date: $HTTP_DATE$\r\n s> Content-Type: text/plain\r\n s> Content-Length: 96\r\n s> \r\n s> APIs can be accessed at /api/<name>, where <name> can be one of the following:\n s> \n s> exp-http-v2-0001