Mercurial > hg
view tests/test-trusted.py.out @ 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 | 75e4bae56068 |
children | 73ccba60aaa1 |
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# same user, same group trusted global = /some/path local = /another/path untrusted . . global = /some/path . . local = /another/path # same user, different group trusted global = /some/path local = /another/path untrusted . . global = /some/path . . local = /another/path # different user, same group not trusting file .hg/hgrc from untrusted user abc, group bar trusted global = /some/path untrusted . . global = /some/path . . local = /another/path # different user, same group, but we trust the group trusted global = /some/path local = /another/path untrusted . . global = /some/path . . local = /another/path # different user, different group not trusting file .hg/hgrc from untrusted user abc, group def trusted global = /some/path untrusted . . global = /some/path . . local = /another/path # different user, different group, but we trust the user trusted global = /some/path local = /another/path untrusted . . global = /some/path . . local = /another/path # different user, different group, but we trust the group trusted global = /some/path local = /another/path untrusted . . global = /some/path . . local = /another/path # different user, different group, but we trust the user and the group trusted global = /some/path local = /another/path untrusted . . global = /some/path . . local = /another/path # we trust all users # different user, different group trusted global = /some/path local = /another/path untrusted . . global = /some/path . . local = /another/path # we trust all groups # different user, different group trusted global = /some/path local = /another/path untrusted . . global = /some/path . . local = /another/path # we trust all users and groups # different user, different group trusted global = /some/path local = /another/path untrusted . . global = /some/path . . local = /another/path # we don't get confused by users and groups with the same name # different user, different group not trusting file .hg/hgrc from untrusted user abc, group def trusted global = /some/path untrusted . . global = /some/path . . local = /another/path # list of user names # different user, different group, but we trust the user trusted global = /some/path local = /another/path untrusted . . global = /some/path . . local = /another/path # list of group names # different user, different group, but we trust the group trusted global = /some/path local = /another/path untrusted . . global = /some/path . . local = /another/path # Can't figure out the name of the user running this process # different user, different group not trusting file .hg/hgrc from untrusted user abc, group def trusted global = /some/path untrusted . . global = /some/path . . local = /another/path # prints debug warnings # different user, different group not trusting file .hg/hgrc from untrusted user abc, group def trusted ignoring untrusted configuration option paths.local = /another/path global = /some/path untrusted . . global = /some/path . ignoring untrusted configuration option paths.local = /another/path . local = /another/path # report_untrusted enabled without debug hides warnings # different user, different group trusted global = /some/path untrusted . . global = /some/path . . local = /another/path # report_untrusted enabled with debug shows warnings # different user, different group not trusting file .hg/hgrc from untrusted user abc, group def trusted ignoring untrusted configuration option paths.local = /another/path global = /some/path untrusted . . global = /some/path . ignoring untrusted configuration option paths.local = /another/path . local = /another/path # ui.readconfig sections quux # read trusted, untrusted, new ui, trusted not trusting file foobar from untrusted user abc, group def trusted: ignoring untrusted configuration option foobar.baz = quux None untrusted: quux # error handling # file doesn't exist # same user, same group # different user, different group # parse error # different user, different group not trusting file .hg/hgrc from untrusted user abc, group def ('foo', '.hg/hgrc:1') # same user, same group ('foo', '.hg/hgrc:1') # access typed information # different user, different group not trusting file .hg/hgrc from untrusted user abc, group def # suboptions, trusted and untrusted (None, []) ('main', [('one', 'one'), ('two', 'two')]) # path, trusted and untrusted None .hg/monty/python # bool, trusted and untrusted False True # int, trusted and untrusted 0 42 # bytes, trusted and untrusted 0 84934656 # list, trusted and untrusted [] ['spam', 'ham', 'eggs']