view tests/test-default-push.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

  $ hg init a

  $ echo a > a/a
  $ hg --cwd a ci -Ama
  adding a

  $ hg clone a c
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ hg clone a b
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ echo b >> b/a
  $ hg --cwd b ci -mb

Push should provide a hint when both 'default' and 'default-push' not set:
  $ cd c
  $ hg push --config paths.default=
  abort: default repository not configured!
  (see 'hg help config.paths')
  [255]

  $ cd ..

Push should push to 'default' when 'default-push' not set:

  $ hg --cwd b push
  pushing to $TESTTMP/a
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files

Push should push to 'default-push' when set:

  $ echo '[paths]' >> b/.hg/hgrc
  $ echo 'default-push = ../c' >> b/.hg/hgrc
  $ hg --cwd b push
  pushing to $TESTTMP/c
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files

But push should push to 'default' if explicitly specified (issue5000):

  $ hg --cwd b push default
  pushing to $TESTTMP/a
  searching for changes
  no changes found
  [1]

Push should push to 'default-push' when 'default' is not set

  $ hg -q clone a push-default-only
  $ cd push-default-only
  $ rm .hg/hgrc

  $ touch foo
  $ hg -q commit -A -m 'add foo'
  $ hg --config paths.default-push=../a push
  pushing to $TESTTMP/a
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files

  $ cd ..

Pushing to a path that isn't defined should not fall back to default

  $ hg --cwd b push doesnotexist
  abort: repository doesnotexist does not exist!
  [255]

:pushurl is used when defined

  $ hg -q clone a pushurlsource
  $ hg -q clone a pushurldest
  $ cd pushurlsource

Windows needs a leading slash to make a URL that passes all of the checks
  $ WD=`pwd`
#if windows
  $ WD="/$WD"
#endif
  $ cat > .hg/hgrc << EOF
  > [paths]
  > default = https://example.com/not/relevant
  > default:pushurl = file://$WD/../pushurldest
  > EOF

  $ touch pushurl
  $ hg -q commit -A -m 'add pushurl'
  $ hg push
  pushing to file:/*/$TESTTMP/pushurlsource/../pushurldest (glob)
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files

:pushrev is used when no -r is passed

  $ cat >> .hg/hgrc << EOF
  > default:pushrev = .
  > EOF
  $ hg -q up -r 0
  $ echo head1 > foo
  $ hg -q commit -A -m head1
  $ hg -q up -r 0
  $ echo head2 > foo
  $ hg -q commit -A -m head2
  $ hg push -f
  pushing to file:/*/$TESTTMP/pushurlsource/../pushurldest (glob)
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)

  $ hg --config 'paths.default:pushrev=draft()' push -f
  pushing to file:/*/$TESTTMP/pushurlsource/../pushurldest (glob)
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)

Invalid :pushrev raises appropriately

  $ hg --config 'paths.default:pushrev=notdefined()' push
  pushing to file:/*/$TESTTMP/pushurlsource/../pushurldest (glob)
  hg: parse error: unknown identifier: notdefined
  [255]

  $ hg --config 'paths.default:pushrev=(' push
  pushing to file:/*/$TESTTMP/pushurlsource/../pushurldest (glob)
  hg: parse error at 1: not a prefix: end
  ((
    ^ here)
  [255]

  $ cd ..