Mercurial > hg
view tests/test-exchange-obsmarkers-case-A1.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 | eb586ed5d8ce |
children | 89630d0b3e23 |
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============================================ Testing obsolescence markers push: Cases A.1 ============================================ Mercurial pushes obsolescences markers relevant to the "pushed-set", the set of all changesets that requested to be "in sync" after the push (even if they are already on both side). This test belongs to a series of tests checking such set is properly computed and applied. This does not tests "obsmarkers" discovery capabilities. Category A: simple cases TestCase 1: pushing a single head Subcases: # A.1.1 pushing a single head (2 variants) # A.1.2 pushing multiple changesets into a single head (2 variants) Case: A.1.1 pushing a single head ================================= .. .. {{{ .. ⇠◔ A .. | .. ● O .. }}} .. .. Marker exists from: .. .. * A .. .. Commands run: .. .. * hg push -r A .. * hg push .. .. Expected exchange: .. .. * chain from A Setup ----- $ . $TESTDIR/testlib/exchange-obsmarker-util.sh initial $ setuprepos A.1.1 creating test repo for test case A.1.1 - pulldest - main - pushdest cd into `main` and proceed with env setup $ cd main $ mkcommit A $ hg debugobsolete aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa `getid 'desc(A)'` $ hg log -G @ f5bc6836db60 (draft): A | o a9bdc8b26820 (public): O $ inspect_obsmarkers obsstore content ================ aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} $ cd .. $ cd .. setup both variants $ cp -R A.1.1 A.1.1.a $ cp -R A.1.1 A.1.1.b Variant a: push -r A -------------------- $ dotest A.1.1.a A ## Running testcase A.1.1.a # testing echange of "A" (f5bc6836db60) ## initial state # obstore: main aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} # obstore: pushdest # obstore: pulldest ## pushing "A" from main to pushdest pushing to pushdest searching for changes remote: adding changesets remote: adding manifests remote: adding file changes remote: added 1 changesets with 1 changes to 1 files remote: 1 new obsolescence markers ## post push state # obstore: main aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} # obstore: pushdest aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} # obstore: pulldest ## pulling "f5bc6836db60" from main into pulldest pulling from main searching for changes adding changesets adding manifests adding file changes added 1 changesets with 1 changes to 1 files 1 new obsolescence markers new changesets f5bc6836db60 (run 'hg update' to get a working copy) ## post pull state # obstore: main aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} # obstore: pushdest aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} # obstore: pulldest aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} Variant b: push --------------- $ dotest A.1.1.b ## Running testcase A.1.1.b ## initial state # obstore: main aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} # obstore: pushdest # obstore: pulldest ## pushing from main to pushdest pushing to pushdest searching for changes remote: adding changesets remote: adding manifests remote: adding file changes remote: added 1 changesets with 1 changes to 1 files remote: 1 new obsolescence markers ## post push state # obstore: main aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} # obstore: pushdest aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} # obstore: pulldest ## pulling from main into pulldest pulling from main searching for changes adding changesets adding manifests adding file changes added 1 changesets with 1 changes to 1 files 1 new obsolescence markers new changesets f5bc6836db60 (run 'hg update' to get a working copy) ## post pull state # obstore: main aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} # obstore: pushdest aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} # obstore: pulldest aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} A.1.2 pushing multiple changesets into a single head ==================================================== .. {{{ .. ◔ B .. | .. ⇠◔ A .. | .. ● O .. }}} .. .. Marker exist from: .. .. * A .. .. Command run: .. .. * hg push -r B .. * hg push .. .. Expected exchange: .. .. * chain from A Setup ----- initial $ setuprepos A.1.2 creating test repo for test case A.1.2 - pulldest - main - pushdest cd into `main` and proceed with env setup $ cd main $ mkcommit A $ mkcommit B $ hg log -G @ f6fbb35d8ac9 (draft): B | o f5bc6836db60 (draft): A | o a9bdc8b26820 (public): O $ hg debugobsolete aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa `getid 'desc(A)'` $ inspect_obsmarkers obsstore content ================ aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} $ cd .. $ cd .. setup both variants $ cp -R A.1.2 A.1.2.a $ cp -R A.1.2 A.1.2.b Variant a: push -r A -------------------- $ dotest A.1.2.a B ## Running testcase A.1.2.a # testing echange of "B" (f6fbb35d8ac9) ## initial state # obstore: main aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} # obstore: pushdest # obstore: pulldest ## pushing "B" from main to pushdest pushing to pushdest searching for changes remote: adding changesets remote: adding manifests remote: adding file changes remote: added 2 changesets with 2 changes to 2 files remote: 1 new obsolescence markers ## post push state # obstore: main aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} # obstore: pushdest aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} # obstore: pulldest ## pulling "f6fbb35d8ac9" from main into pulldest pulling from main searching for changes adding changesets adding manifests adding file changes added 2 changesets with 2 changes to 2 files 1 new obsolescence markers new changesets f5bc6836db60:f6fbb35d8ac9 (run 'hg update' to get a working copy) ## post pull state # obstore: main aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} # obstore: pushdest aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} # obstore: pulldest aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} Variant b: push --------------- $ dotest A.1.2.b ## Running testcase A.1.2.b ## initial state # obstore: main aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} # obstore: pushdest # obstore: pulldest ## pushing from main to pushdest pushing to pushdest searching for changes remote: adding changesets remote: adding manifests remote: adding file changes remote: added 2 changesets with 2 changes to 2 files remote: 1 new obsolescence markers ## post push state # obstore: main aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} # obstore: pushdest aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} # obstore: pulldest ## pulling from main into pulldest pulling from main searching for changes adding changesets adding manifests adding file changes added 2 changesets with 2 changes to 2 files 1 new obsolescence markers new changesets f5bc6836db60:f6fbb35d8ac9 (run 'hg update' to get a working copy) ## post pull state # obstore: main aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} # obstore: pushdest aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'} # obstore: pulldest aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa f5bc6836db60e308a17ba08bf050154ba9c4fad7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}