Mercurial > hg
view tests/test-rebase-inmemory.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 | b3d0c97a0820 |
children | 95bd19f60957 |
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#require symlink execbit $ cat << EOF >> $HGRCPATH > [extensions] > amend= > rebase= > debugdrawdag=$TESTDIR/drawdag.py > strip= > [rebase] > experimental.inmemory=1 > [diff] > git=1 > [alias] > tglog = log -G --template "{rev}: {node|short} '{desc}'\n" > EOF Rebase a simple DAG: $ hg init repo1 $ cd repo1 $ hg debugdrawdag <<'EOS' > c b > |/ > d > | > a > EOS $ hg up -C a 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg tglog o 3: 814f6bd05178 'c' | | o 2: db0e82a16a62 'b' |/ o 1: 02952614a83d 'd' | @ 0: b173517d0057 'a' $ hg cat -r 3 c c (no-eol) $ hg cat -r 2 b b (no-eol) $ hg rebase --debug -r b -d c | grep rebasing rebasing in-memory rebasing 2:db0e82a16a62 "b" (b) $ hg tglog o 3: ca58782ad1e4 'b' | o 2: 814f6bd05178 'c' | o 1: 02952614a83d 'd' | @ 0: b173517d0057 'a' $ hg cat -r 3 b b (no-eol) $ hg cat -r 2 c c (no-eol) Case 2: $ hg init repo2 $ cd repo2 $ hg debugdrawdag <<'EOS' > c b > |/ > d > | > a > EOS Add a symlink and executable file: $ hg up -C c 3 files updated, 0 files merged, 0 files removed, 0 files unresolved $ ln -s somefile e $ echo f > f $ chmod +x f $ hg add e f $ hg amend -q $ hg up -Cq a Write files to the working copy, and ensure they're still there after the rebase $ echo "abc" > a $ ln -s def b $ echo "ghi" > c $ echo "jkl" > d $ echo "mno" > e $ hg tglog o 3: f56b71190a8f 'c' | | o 2: db0e82a16a62 'b' |/ o 1: 02952614a83d 'd' | @ 0: b173517d0057 'a' $ hg cat -r 3 c c (no-eol) $ hg cat -r 2 b b (no-eol) $ hg cat -r 3 e somefile (no-eol) $ hg rebase --debug -s b -d a | grep rebasing rebasing in-memory rebasing 2:db0e82a16a62 "b" (b) $ hg tglog o 3: fc055c3b4d33 'b' | | o 2: f56b71190a8f 'c' | | | o 1: 02952614a83d 'd' |/ @ 0: b173517d0057 'a' $ hg cat -r 2 c c (no-eol) $ hg cat -r 3 b b (no-eol) $ hg rebase --debug -s 1 -d 3 | grep rebasing rebasing in-memory rebasing 1:02952614a83d "d" (d) rebasing 2:f56b71190a8f "c" $ hg tglog o 3: 753feb6fd12a 'c' | o 2: 09c044d2cb43 'd' | o 1: fc055c3b4d33 'b' | @ 0: b173517d0057 'a' Ensure working copy files are still there: $ cat a abc $ readlink.py b b -> def $ cat e mno Ensure symlink and executable files were rebased properly: $ hg up -Cq 3 $ readlink.py e e -> somefile $ ls -l f | cut -c -10 -rwxr-xr-x Rebase the working copy parent $ hg up -C 3 0 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg rebase -r 3 -d 0 --debug | grep rebasing rebasing in-memory rebasing 3:753feb6fd12a "c" (tip) $ hg tglog @ 3: 844a7de3e617 'c' | | o 2: 09c044d2cb43 'd' | | | o 1: fc055c3b4d33 'b' |/ o 0: b173517d0057 'a' Test dry-run rebasing $ hg init repo3 $ cd repo3 $ echo a>a $ hg ci -Aqma $ echo b>b $ hg ci -Aqmb $ echo c>c $ hg ci -Aqmc $ echo d>d $ hg ci -Aqmd $ echo e>e $ hg ci -Aqme $ hg up 1 -q $ echo f>f $ hg ci -Amf adding f created new head $ echo g>g $ hg ci -Aqmg $ hg log -G --template "{rev}:{short(node)} {person(author)}\n{firstline(desc)} {topic}\n\n" @ 6:baf10c5166d4 test | g | o 5:6343ca3eff20 test | f | | o 4:e860deea161a test | | e | | | o 3:055a42cdd887 test | | d | | | o 2:177f92b77385 test |/ c | o 1:d2ae7f538514 test | b | o 0:cb9a9f314b8b test a Make sure it throws error while passing --continue or --abort with --dry-run $ hg rebase -s 2 -d 6 -n --continue abort: cannot specify both --dry-run and --continue [255] $ hg rebase -s 2 -d 6 -n --abort abort: cannot specify both --dry-run and --abort [255] Check dryrun gives correct results when there is no conflict in rebasing $ hg rebase -s 2 -d 6 -n starting dry-run rebase; repository will not be changed rebasing 2:177f92b77385 "c" rebasing 3:055a42cdd887 "d" rebasing 4:e860deea161a "e" dry-run rebase completed successfully; run without -n/--dry-run to perform this rebase $ hg diff $ hg status $ hg log -G --template "{rev}:{short(node)} {person(author)}\n{firstline(desc)} {topic}\n\n" @ 6:baf10c5166d4 test | g | o 5:6343ca3eff20 test | f | | o 4:e860deea161a test | | e | | | o 3:055a42cdd887 test | | d | | | o 2:177f92b77385 test |/ c | o 1:d2ae7f538514 test | b | o 0:cb9a9f314b8b test a Check dryrun working with --collapse when there is no conflict $ hg rebase -s 2 -d 6 -n --collapse starting dry-run rebase; repository will not be changed rebasing 2:177f92b77385 "c" rebasing 3:055a42cdd887 "d" rebasing 4:e860deea161a "e" dry-run rebase completed successfully; run without -n/--dry-run to perform this rebase Check dryrun gives correct results when there is conflict in rebasing Make a conflict: $ hg up 6 -q $ echo conflict>e $ hg ci -Aqm "conflict with e" $ hg log -G --template "{rev}:{short(node)} {person(author)}\n{firstline(desc)} {topic}\n\n" @ 7:d2c195b28050 test | conflict with e | o 6:baf10c5166d4 test | g | o 5:6343ca3eff20 test | f | | o 4:e860deea161a test | | e | | | o 3:055a42cdd887 test | | d | | | o 2:177f92b77385 test |/ c | o 1:d2ae7f538514 test | b | o 0:cb9a9f314b8b test a $ hg rebase -s 2 -d 7 -n starting dry-run rebase; repository will not be changed rebasing 2:177f92b77385 "c" rebasing 3:055a42cdd887 "d" rebasing 4:e860deea161a "e" merging e transaction abort! rollback completed hit a merge conflict [1] $ hg diff $ hg status $ hg log -G --template "{rev}:{short(node)} {person(author)}\n{firstline(desc)} {topic}\n\n" @ 7:d2c195b28050 test | conflict with e | o 6:baf10c5166d4 test | g | o 5:6343ca3eff20 test | f | | o 4:e860deea161a test | | e | | | o 3:055a42cdd887 test | | d | | | o 2:177f92b77385 test |/ c | o 1:d2ae7f538514 test | b | o 0:cb9a9f314b8b test a Check dryrun working with --collapse when there is conflicts $ hg rebase -s 2 -d 7 -n --collapse starting dry-run rebase; repository will not be changed rebasing 2:177f92b77385 "c" rebasing 3:055a42cdd887 "d" rebasing 4:e860deea161a "e" merging e hit a merge conflict [1] ========================== Test for --confirm option| ========================== $ cd .. $ hg clone repo3 repo4 -q $ cd repo4 $ hg strip 7 -q $ hg log -G --template "{rev}:{short(node)} {person(author)}\n{firstline(desc)} {topic}\n\n" @ 6:baf10c5166d4 test | g | o 5:6343ca3eff20 test | f | | o 4:e860deea161a test | | e | | | o 3:055a42cdd887 test | | d | | | o 2:177f92b77385 test |/ c | o 1:d2ae7f538514 test | b | o 0:cb9a9f314b8b test a Check it gives error when both --dryrun and --confirm is used: $ hg rebase -s 2 -d . --confirm --dry-run abort: cannot specify both --confirm and --dry-run [255] $ hg rebase -s 2 -d . --confirm --abort abort: cannot specify both --confirm and --abort [255] $ hg rebase -s 2 -d . --confirm --continue abort: cannot specify both --confirm and --continue [255] Test --confirm option when there are no conflicts: $ hg rebase -s 2 -d . --keep --config ui.interactive=True --confirm << EOF > n > EOF starting in-memory rebase rebasing 2:177f92b77385 "c" rebasing 3:055a42cdd887 "d" rebasing 4:e860deea161a "e" rebase completed successfully apply changes (yn)? n $ hg log -G --template "{rev}:{short(node)} {person(author)}\n{firstline(desc)} {topic}\n\n" @ 6:baf10c5166d4 test | g | o 5:6343ca3eff20 test | f | | o 4:e860deea161a test | | e | | | o 3:055a42cdd887 test | | d | | | o 2:177f92b77385 test |/ c | o 1:d2ae7f538514 test | b | o 0:cb9a9f314b8b test a $ hg rebase -s 2 -d . --keep --config ui.interactive=True --confirm << EOF > y > EOF starting in-memory rebase rebasing 2:177f92b77385 "c" rebasing 3:055a42cdd887 "d" rebasing 4:e860deea161a "e" rebase completed successfully apply changes (yn)? y $ hg log -G --template "{rev}:{short(node)} {person(author)}\n{firstline(desc)} {topic}\n\n" o 9:9fd28f55f6dc test | e | o 8:12cbf031f469 test | d | o 7:c83b1da5b1ae test | c | @ 6:baf10c5166d4 test | g | o 5:6343ca3eff20 test | f | | o 4:e860deea161a test | | e | | | o 3:055a42cdd887 test | | d | | | o 2:177f92b77385 test |/ c | o 1:d2ae7f538514 test | b | o 0:cb9a9f314b8b test a Test --confirm option when there is a conflict $ hg up tip -q $ echo ee>e $ hg ci --amend -m "conflict with e" -q $ hg log -G --template "{rev}:{short(node)} {person(author)}\n{firstline(desc)} {topic}\n\n" @ 9:906d72f66a59 test | conflict with e | o 8:12cbf031f469 test | d | o 7:c83b1da5b1ae test | c | o 6:baf10c5166d4 test | g | o 5:6343ca3eff20 test | f | | o 4:e860deea161a test | | e | | | o 3:055a42cdd887 test | | d | | | o 2:177f92b77385 test |/ c | o 1:d2ae7f538514 test | b | o 0:cb9a9f314b8b test a $ hg rebase -s 4 -d . --keep --confirm starting in-memory rebase rebasing 4:e860deea161a "e" merging e hit a merge conflict [1] $ hg log -G --template "{rev}:{short(node)} {person(author)}\n{firstline(desc)} {topic}\n\n" @ 9:906d72f66a59 test | conflict with e | o 8:12cbf031f469 test | d | o 7:c83b1da5b1ae test | c | o 6:baf10c5166d4 test | g | o 5:6343ca3eff20 test | f | | o 4:e860deea161a test | | e | | | o 3:055a42cdd887 test | | d | | | o 2:177f92b77385 test |/ c | o 1:d2ae7f538514 test | b | o 0:cb9a9f314b8b test a