view tests/test-removeemptydirs.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 for experimental.removeemptydirs

  $ NO_RM=--config=experimental.removeemptydirs=0
  $ isdir() { if [ -d $1 ]; then echo yes; else echo no; fi }
  $ isfile() { if [ -f $1 ]; then echo yes; else echo no; fi }

`hg rm` of the last file in a directory:
  $ hg init hgrm
  $ cd hgrm
  $ mkdir somedir
  $ echo hi > somedir/foo
  $ hg ci -qAm foo
  $ isdir somedir
  yes
  $ hg rm somedir/foo
  $ isdir somedir
  no
  $ hg revert -qa
  $ isdir somedir
  yes
  $ hg $NO_RM rm somedir/foo
  $ isdir somedir
  yes
  $ ls somedir
  $ cd $TESTTMP

`hg mv` of the last file in a directory:
  $ hg init hgmv
  $ cd hgmv
  $ mkdir somedir
  $ mkdir destdir
  $ echo hi > somedir/foo
  $ hg ci -qAm foo
  $ isdir somedir
  yes
  $ hg mv somedir/foo destdir/foo
  $ isdir somedir
  no
  $ hg revert -qa
(revert doesn't get rid of destdir/foo?)
  $ rm destdir/foo
  $ isdir somedir
  yes
  $ hg $NO_RM mv somedir/foo destdir/foo
  $ isdir somedir
  yes
  $ ls somedir
  $ cd $TESTTMP

Updating to a commit that doesn't have the directory:
  $ hg init hgupdate
  $ cd hgupdate
  $ echo hi > r0
  $ hg ci -qAm r0
  $ mkdir somedir
  $ echo hi > somedir/foo
  $ hg ci -qAm r1
  $ isdir somedir
  yes
  $ hg co -q -r ".^"
  $ isdir somedir
  no
  $ hg co -q tip
  $ isdir somedir
  yes
  $ hg $NO_RM co -q -r ".^"
  $ isdir somedir
  yes
  $ ls somedir
  $ cd $TESTTMP

Rebasing across a commit that doesn't have the directory, from inside the
directory:
  $ hg init hgrebase
  $ cd hgrebase
  $ echo hi > r0
  $ hg ci -qAm r0
  $ mkdir somedir
  $ echo hi > somedir/foo
  $ hg ci -qAm first_rebase_source
  $ hg $NO_RM co -q -r ".^"
  $ echo hi > somedir/bar
  $ hg ci -qAm first_rebase_dest
  $ hg $NO_RM co -q -r ".^"
  $ echo hi > somedir/baz
  $ hg ci -qAm second_rebase_dest
  $ hg co -qr 'desc(first_rebase_source)'
  $ cd $TESTTMP/hgrebase/somedir
  $ hg --config extensions.rebase= rebase -qr . -d 'desc(first_rebase_dest)'
  current directory was removed
  (consider changing to repo root: $TESTTMP/hgrebase)
  $ cd $TESTTMP/hgrebase/somedir
(The current node is the rebased first_rebase_source on top of
first_rebase_dest)
This should not output anything about current directory being removed:
  $ hg $NO_RM --config extensions.rebase= rebase -qr . -d 'desc(second_rebase_dest)'
  $ cd $TESTTMP

Histediting across a commit that doesn't have the directory, from inside the
directory (reordering nodes):
  $ hg init hghistedit
  $ cd hghistedit
  $ echo hi > r0
  $ hg ci -qAm r0
  $ echo hi > r1
  $ hg ci -qAm r1
  $ echo hi > r2
  $ hg ci -qAm r2
  $ mkdir somedir
  $ echo hi > somedir/foo
  $ hg ci -qAm migrating_revision
  $ cat > histedit_commands <<EOF
  > pick 89079fab8aee 0 r0
  > pick e6d271df3142 1 r1
  > pick 89e25aa83f0f 3 migrating_revision
  > pick b550aa12d873 2 r2
  > EOF
  $ cd $TESTTMP/hghistedit/somedir
  $ hg --config extensions.histedit= histedit -q --commands ../histedit_commands

histedit doesn't output anything when the current diretory is removed. We rely
on the tests being commonly run on machines where the current directory
disappearing from underneath us actually has an observable effect, such as an
error or no files listed
#if linuxormacos
  $ isfile foo
  no
#endif
  $ cd $TESTTMP/hghistedit/somedir
  $ isfile foo
  yes

  $ cd $TESTTMP/hghistedit
  $ cat > histedit_commands <<EOF
  > pick 89079fab8aee 0 r0
  > pick 7c7a22c6009f 3 migrating_revision
  > pick e6d271df3142 1 r1
  > pick 40a53c2d4276 2 r2
  > EOF
  $ cd $TESTTMP/hghistedit/somedir
  $ hg $NO_RM --config extensions.histedit= histedit -q --commands ../histedit_commands
Regardless of system, we should always get a 'yes' here.
  $ isfile foo
  yes
  $ cd $TESTTMP

This is essentially the exact test from issue5826, just cleaned up a little:

  $ hg init issue5826_withrm
  $ cd issue5826_withrm

Let's only turn this on for this repo so that we don't contaminate later tests.
  $ cat >> .hg/hgrc <<EOF
  > [extensions]
  > histedit =
  > EOF
Commit three revisions that each create a directory:

  $ mkdir foo
  $ touch foo/bar
  $ hg commit -qAm "add foo"

  $ mkdir bar
  $ touch bar/bar
  $ hg commit -qAm "add bar"

  $ mkdir baz
  $ touch baz/bar
  $ hg commit -qAm "add baz"

Enter the first directory:

  $ cd foo

Histedit doing 'pick, pick, fold':

  $ hg histedit --commands /dev/stdin <<EOF
  > pick 6274c77c93c3 1 add bar
  > pick ff70a87b588f 0 add foo
  > fold 9992bb0ac0db 2 add baz
  > EOF
  abort: $ENOENT$
  [255]

Go back to the repo root after losing it as part of that operation:
  $ cd $TESTTMP/issue5826_withrm

Note the lack of a non-zero exit code from this function - it exits
successfully, but doesn't really do anything.
  $ hg histedit --continue
  9992bb0ac0db: cannot fold - working copy is not a descendant of previous commit 5c806432464a
  saved backup bundle to $TESTTMP/issue5826_withrm/.hg/strip-backup/ff70a87b588f-e94f9789-histedit.hg

  $ hg log -T '{rev}:{node|short} {desc}\n'
  2:94e3f9fae1d6 fold-temp-revision 9992bb0ac0db
  1:5c806432464a add foo
  0:d17db4b0303a add bar

Now test that again with experimental.removeemptydirs=false:
  $ hg init issue5826_norm
  $ cd issue5826_norm

Let's only turn this on for this repo so that we don't contaminate later tests.
  $ cat >> .hg/hgrc <<EOF
  > [extensions]
  > histedit =
  > [experimental]
  > removeemptydirs = false
  > EOF
Commit three revisions that each create a directory:

  $ mkdir foo
  $ touch foo/bar
  $ hg commit -qAm "add foo"

  $ mkdir bar
  $ touch bar/bar
  $ hg commit -qAm "add bar"

  $ mkdir baz
  $ touch baz/bar
  $ hg commit -qAm "add baz"

Enter the first directory:

  $ cd foo

Histedit doing 'pick, pick, fold':

  $ hg histedit --commands /dev/stdin <<EOF
  > pick 6274c77c93c3 1 add bar
  > pick ff70a87b588f 0 add foo
  > fold 9992bb0ac0db 2 add baz
  > EOF
  saved backup bundle to $TESTTMP/issue5826_withrm/issue5826_norm/.hg/strip-backup/5c806432464a-cd4c8d86-histedit.hg

Note the lack of a 'cd' being necessary here, and we don't need to 'histedit
--continue'

  $ hg log -T '{rev}:{node|short} {desc}\n'
  1:b9eddaa97cbc add foo
  ***
  add baz
  0:d17db4b0303a add bar

  $ cd $TESTTMP

Testing `hg split` being run from inside of a directory that was created in the
commit being split:

  $ hg init hgsplit
  $ cd hgsplit
  $ cat >> .hg/hgrc << EOF
  > [ui]
  > interactive = 1
  > [extensions]
  > split =
  > EOF
  $ echo anchor > anchor.txt
  $ hg ci -qAm anchor

Create a changeset with '/otherfile_in_root' and 'somedir/foo', then try to
split it.
  $ echo otherfile > otherfile_in_root
  $ mkdir somedir
  $ cd somedir
  $ echo hi > foo
  $ hg ci -qAm split_me
(Note: need to make this file not in this directory, or else the bug doesn't
reproduce; we're using a separate file due to concerns of portability on
`echo -e`)
  $ cat > ../split_commands << EOF
  > n
  > y
  > y
  > a
  > EOF
  $ cat ../split_commands | hg split
  current directory was removed
  (consider changing to repo root: $TESTTMP/hgsplit)
  diff --git a/otherfile_in_root b/otherfile_in_root
  new file mode 100644
  examine changes to 'otherfile_in_root'? [Ynesfdaq?] n
  
  diff --git a/somedir/foo b/somedir/foo
  new file mode 100644
  examine changes to 'somedir/foo'? [Ynesfdaq?] y
  
  @@ -0,0 +1,1 @@
  +hi
  record change 2/2 to 'somedir/foo'? [Ynesfdaq?] y
  
  abort: $ENOENT$
  [255]

Let's try that again without the rmdir
  $ cd $TESTTMP/hgsplit/somedir
Show that the previous split didn't do anything
  $ hg log -T '{rev}:{node|short} {desc}\n'
  1:e26b22a4f0b7 split_me
  0:7e53273730c0 anchor
  $ hg status
  ? split_commands
Try again
  $ cat ../split_commands | hg $NO_RM split
  diff --git a/otherfile_in_root b/otherfile_in_root
  new file mode 100644
  examine changes to 'otherfile_in_root'? [Ynesfdaq?] n
  
  diff --git a/somedir/foo b/somedir/foo
  new file mode 100644
  examine changes to 'somedir/foo'? [Ynesfdaq?] y
  
  @@ -0,0 +1,1 @@
  +hi
  record change 2/2 to 'somedir/foo'? [Ynesfdaq?] y
  
  created new head
  diff --git a/otherfile_in_root b/otherfile_in_root
  new file mode 100644
  examine changes to 'otherfile_in_root'? [Ynesfdaq?] a
  
  saved backup bundle to $TESTTMP/hgsplit/.hg/strip-backup/*-split.hg (glob)
Show that this split did something
  $ hg log -T '{rev}:{node|short} {desc}\n'
  2:a440f24fca4f split_me
  1:c994f20276ab split_me
  0:7e53273730c0 anchor
  $ hg status
  ? split_commands