view tests/test-status-rev.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

Tests of 'hg status --rev <rev>' to make sure status between <rev> and '.' get
combined correctly with the dirstate status.

  $ hg init

First commit

  $ $PYTHON $TESTDIR/generate-working-copy-states.py state 2 1
  $ hg addremove --similarity 0
  adding content1_content1_content1-tracked
  adding content1_content1_content1-untracked
  adding content1_content1_content3-tracked
  adding content1_content1_content3-untracked
  adding content1_content1_missing-tracked
  adding content1_content1_missing-untracked
  adding content1_content2_content1-tracked
  adding content1_content2_content1-untracked
  adding content1_content2_content2-tracked
  adding content1_content2_content2-untracked
  adding content1_content2_content3-tracked
  adding content1_content2_content3-untracked
  adding content1_content2_missing-tracked
  adding content1_content2_missing-untracked
  adding content1_missing_content1-tracked
  adding content1_missing_content1-untracked
  adding content1_missing_content3-tracked
  adding content1_missing_content3-untracked
  adding content1_missing_missing-tracked
  adding content1_missing_missing-untracked
  $ hg commit -m first

Second commit

  $ $PYTHON $TESTDIR/generate-working-copy-states.py state 2 2
  $ hg addremove --similarity 0
  removing content1_missing_content1-tracked
  removing content1_missing_content1-untracked
  removing content1_missing_content3-tracked
  removing content1_missing_content3-untracked
  removing content1_missing_missing-tracked
  removing content1_missing_missing-untracked
  adding missing_content2_content2-tracked
  adding missing_content2_content2-untracked
  adding missing_content2_content3-tracked
  adding missing_content2_content3-untracked
  adding missing_content2_missing-tracked
  adding missing_content2_missing-untracked
  $ hg commit -m second

Working copy

  $ $PYTHON $TESTDIR/generate-working-copy-states.py state 2 wc
  $ hg addremove --similarity 0
  adding content1_missing_content1-tracked
  adding content1_missing_content1-untracked
  adding content1_missing_content3-tracked
  adding content1_missing_content3-untracked
  adding content1_missing_missing-tracked
  adding content1_missing_missing-untracked
  adding missing_missing_content3-tracked
  adding missing_missing_content3-untracked
  adding missing_missing_missing-tracked
  adding missing_missing_missing-untracked
  $ hg forget *_*_*-untracked
  $ rm *_*_missing-*

Status compared to parent of the working copy, i.e. the dirstate status

  $ hg status -A --rev 1 'glob:missing_content2_content3-tracked'
  M missing_content2_content3-tracked
  $ hg status -A --rev 1 'glob:missing_content2_content2-tracked'
  C missing_content2_content2-tracked
  $ hg status -A --rev 1 'glob:missing_missing_content3-tracked'
  A missing_missing_content3-tracked
  $ hg status -A --rev 1 'glob:missing_missing_content3-untracked'
  ? missing_missing_content3-untracked
  $ hg status -A --rev 1 'glob:missing_content2_*-untracked'
  R missing_content2_content2-untracked
  R missing_content2_content3-untracked
  R missing_content2_missing-untracked
  $ hg status -A --rev 1 'glob:missing_*_missing-tracked'
  ! missing_content2_missing-tracked
  ! missing_missing_missing-tracked

  $ hg status -A --rev 1 'glob:missing_missing_missing-untracked'
  missing_missing_missing-untracked: $ENOENT$

Status between first and second commit. Should ignore dirstate status.

  $ hg status -A --rev 0:1 'glob:content1_content2_*'
  M content1_content2_content1-tracked
  M content1_content2_content1-untracked
  M content1_content2_content2-tracked
  M content1_content2_content2-untracked
  M content1_content2_content3-tracked
  M content1_content2_content3-untracked
  M content1_content2_missing-tracked
  M content1_content2_missing-untracked
  $ hg status -A --rev 0:1 'glob:content1_content1_*'
  C content1_content1_content1-tracked
  C content1_content1_content1-untracked
  C content1_content1_content3-tracked
  C content1_content1_content3-untracked
  C content1_content1_missing-tracked
  C content1_content1_missing-untracked
  $ hg status -A --rev 0:1 'glob:missing_content2_*'
  A missing_content2_content2-tracked
  A missing_content2_content2-untracked
  A missing_content2_content3-tracked
  A missing_content2_content3-untracked
  A missing_content2_missing-tracked
  A missing_content2_missing-untracked
  $ hg status -A --rev 0:1 'glob:content1_missing_*'
  R content1_missing_content1-tracked
  R content1_missing_content1-untracked
  R content1_missing_content3-tracked
  R content1_missing_content3-untracked
  R content1_missing_missing-tracked
  R content1_missing_missing-untracked
  $ hg status -A --rev 0:1 'glob:missing_missing_*'

Status compared to one revision back, checking that the dirstate status
is correctly combined with the inter-revision status

  $ hg status -A --rev 0 'glob:content1_*_content[23]-tracked'
  M content1_content1_content3-tracked
  M content1_content2_content2-tracked
  M content1_content2_content3-tracked
  M content1_missing_content3-tracked
  $ hg status -A --rev 0 'glob:content1_*_content1-tracked'
  C content1_content1_content1-tracked
  C content1_content2_content1-tracked
  C content1_missing_content1-tracked
  $ hg status -A --rev 0 'glob:missing_*_content?-tracked'
  A missing_content2_content2-tracked
  A missing_content2_content3-tracked
  A missing_missing_content3-tracked
BROKEN: missing_content2_content[23]-untracked exist, so should be listed
  $ hg status -A --rev 0 'glob:missing_*_content?-untracked'
  ? missing_missing_content3-untracked
  $ hg status -A --rev 0 'glob:content1_*_*-untracked'
  R content1_content1_content1-untracked
  R content1_content1_content3-untracked
  R content1_content1_missing-untracked
  R content1_content2_content1-untracked
  R content1_content2_content2-untracked
  R content1_content2_content3-untracked
  R content1_content2_missing-untracked
  R content1_missing_content1-untracked
  R content1_missing_content3-untracked
  R content1_missing_missing-untracked
  $ hg status -A --rev 0 'glob:*_*_missing-tracked'
  ! content1_content1_missing-tracked
  ! content1_content2_missing-tracked
  ! content1_missing_missing-tracked
  ! missing_content2_missing-tracked
  ! missing_missing_missing-tracked
  $ hg status -A --rev 0 'glob:missing_*_missing-untracked'