view tests/test-copy.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

  $ mkdir part1
  $ cd part1

  $ hg init
  $ echo a > a
  $ hg add a
  $ hg commit -m "1"
  $ hg status
  $ hg copy a b
  $ hg --config ui.portablefilenames=abort copy a con.xml
  abort: filename contains 'con', which is reserved on Windows: con.xml
  [255]
  $ hg status
  A b
  $ hg sum
  parent: 0:c19d34741b0a tip
   1
  branch: default
  commit: 1 copied
  update: (current)
  phases: 1 draft
  $ hg --debug commit -m "2"
  committing files:
  b
   b: copy a:b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3
  committing manifest
  committing changelog
  updating the branch cache
  committed changeset 1:93580a2c28a50a56f63526fb305067e6fbf739c4

we should see two history entries

  $ hg history -v
  changeset:   1:93580a2c28a5
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       b
  description:
  2
  
  
  changeset:   0:c19d34741b0a
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       a
  description:
  1
  
  

we should see one log entry for a

  $ hg log a
  changeset:   0:c19d34741b0a
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     1
  

this should show a revision linked to changeset 0

  $ hg debugindex a
     rev linkrev nodeid       p1           p2
       0       0 b789fdd96dc2 000000000000 000000000000

we should see one log entry for b

  $ hg log b
  changeset:   1:93580a2c28a5
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     2
  

this should show a revision linked to changeset 1

  $ hg debugindex b
     rev linkrev nodeid       p1           p2
       0       1 37d9b5d994ea 000000000000 000000000000

this should show the rename information in the metadata

  $ hg debugdata b 0 | head -3 | tail -2
  copy: a
  copyrev: b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3

#if reporevlogstore
  $ md5sum.py .hg/store/data/b.i
  44913824c8f5890ae218f9829535922e  .hg/store/data/b.i
#endif
  $ hg cat b > bsum
  $ md5sum.py bsum
  60b725f10c9c85c70d97880dfe8191b3  bsum
  $ hg cat a > asum
  $ md5sum.py asum
  60b725f10c9c85c70d97880dfe8191b3  asum
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  2 files, 2 changesets, 2 total revisions

  $ cd ..


  $ mkdir part2
  $ cd part2

  $ hg init
  $ echo foo > foo
should fail - foo is not managed
  $ hg mv foo bar
  foo: not copying - file is not managed
  abort: no files to copy
  [255]
  $ hg st -A
  ? foo
  $ hg add foo
dry-run; print a warning that this is not a real copy; foo is added
  $ hg mv --dry-run foo bar
  foo has not been committed yet, so no copy data will be stored for bar.
  $ hg st -A
  A foo
should print a warning that this is not a real copy; bar is added
  $ hg mv foo bar
  foo has not been committed yet, so no copy data will be stored for bar.
  $ hg st -A
  A bar
should print a warning that this is not a real copy; foo is added
  $ hg cp bar foo
  bar has not been committed yet, so no copy data will be stored for foo.
  $ hg rm -f bar
  $ rm bar
  $ hg st -A
  A foo
  $ hg commit -m1

moving a missing file
  $ rm foo
  $ hg mv foo foo3
  foo: deleted in working directory
  foo3 does not exist!
  $ hg up -qC .

copy --after to a nonexistent target filename
  $ hg cp -A foo dummy
  foo: not recording copy - dummy does not exist

dry-run; should show that foo is clean
  $ hg copy --dry-run foo bar
  $ hg st -A
  C foo
should show copy
  $ hg copy foo bar
  $ hg st -C
  A bar
    foo

shouldn't show copy
  $ hg commit -m2
  $ hg st -C

should match
  $ hg debugindex foo
     rev linkrev nodeid       p1           p2
       0       0 2ed2a3912a0b 000000000000 000000000000
  $ hg debugrename bar
  bar renamed from foo:2ed2a3912a0b24502043eae84ee4b279c18b90dd

  $ echo bleah > foo
  $ echo quux > bar
  $ hg commit -m3

should not be renamed
  $ hg debugrename bar
  bar not renamed

  $ hg copy -f foo bar
should show copy
  $ hg st -C
  M bar
    foo

XXX: filtering lfilesrepo.status() in 3.3-rc causes the copy source to not be
displayed.
  $ hg st -C --config extensions.largefiles=
  The fsmonitor extension is incompatible with the largefiles extension and has been disabled. (fsmonitor !)
  M bar
    foo

  $ hg commit -m3

should show no parents for tip
  $ hg debugindex bar
     rev linkrev nodeid       p1           p2
       0       1 7711d36246cc 000000000000 000000000000
       1       2 bdf70a2b8d03 7711d36246cc 000000000000
       2       3 b2558327ea8d 000000000000 000000000000
should match
  $ hg debugindex foo
     rev linkrev nodeid       p1           p2
       0       0 2ed2a3912a0b 000000000000 000000000000
       1       2 dd12c926cf16 2ed2a3912a0b 000000000000
  $ hg debugrename bar
  bar renamed from foo:dd12c926cf165e3eb4cf87b084955cb617221c17

should show no copies
  $ hg st -C

copy --after on an added file
  $ cp bar baz
  $ hg add baz
  $ hg cp -A bar baz
  $ hg st -C
  A baz
    bar

foo was clean:
  $ hg st -AC foo
  C foo
Trying to copy on top of an existing file fails,
  $ hg copy -A bar foo
  foo: not overwriting - file already committed
  (hg copy --after --force to replace the file by recording a copy)
same error without the --after, so the user doesn't have to go through
two hints:
  $ hg copy bar foo
  foo: not overwriting - file already committed
  (hg copy --force to replace the file by recording a copy)
but it's considered modified after a copy --after --force
  $ hg copy -Af bar foo
  $ hg st -AC foo
  M foo
    bar
The hint for a file that exists but is not in file history doesn't
mention --force:
  $ touch xyzzy
  $ hg cp bar xyzzy
  xyzzy: not overwriting - file exists
  (hg copy --after to record the copy)

  $ cd ..