view tests/test-http-branchmap.t @ 17616:9535a0dc41f2

store: implement fncache basic path encoding in C

(This is not yet enabled; it will be turned on in a followup patch.)

The path encoding performed by fncache is complex and (perhaps
surprisingly) slow enough to negatively affect the overall performance
of Mercurial.

For a short path (< 120 bytes), the Python code can be reduced to a fairly
tractable state machine that either determines that nothing needs to be
done in a single pass, or performs the encoding in a second pass.

For longer paths, we avoid the more complicated hashed encoding scheme
for now, and fall back to Python.

Raw performance: I measured in a repo containing 150,000 files in its tip
manifest, with a median path name length of 57 bytes, and 95th percentile
of 96 bytes.

In this repo, the Python code takes 3.1 seconds to encode all path
names, while the hybrid C-and-Python code (called from Python) takes
0.21 seconds, for a speedup of about 14.

Across several other large repositories, I've measured the speedup from
the C code at between 26x and 40x.

For path names above 120 bytes where we must fall back to Python for
hashed encoding, the speedup is about 1.7x.  Thus absolute performance
will depend strongly on the characteristics of a particular repository.

  $ "$TESTDIR/hghave" killdaemons || exit 80

  $ hgserve() {
  >     hg serve -a localhost -p $HGPORT1 -d --pid-file=hg.pid \
  >       -E errors.log -v $@ > startup.log
  >     # Grepping hg serve stdout would hang on Windows
  >     grep -v 'listening at' startup.log
  >     cat hg.pid >> "$DAEMON_PIDS"
  > }
  $ hg init a
  $ hg --encoding utf-8 -R a branch æ
  marked working directory as branch \xc3\xa6 (esc)
  (branches are permanent and global, did you want a bookmark?)
  $ echo foo > a/foo
  $ hg -R a ci -Am foo
  adding foo
  $ hgserve -R a --config web.push_ssl=False --config web.allow_push=* --encoding latin1
  $ hg --encoding utf-8 clone http://localhost:$HGPORT1 b
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  updating to branch \xc3\xa6 (esc)
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg --encoding utf-8 -R b log
  changeset:   0:867c11ce77b8
  branch:      \xc3\xa6 (esc)
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     foo
  
  $ echo bar >> b/foo
  $ hg -R b ci -m bar
  $ hg --encoding utf-8 -R b push
  pushing to http://localhost:$HGPORT1/
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 1 changes to 1 files
  $ hg -R a --encoding utf-8 log
  changeset:   1:58e7c90d67cb
  branch:      \xc3\xa6 (esc)
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     bar
  
  changeset:   0:867c11ce77b8
  branch:      \xc3\xa6 (esc)
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     foo
  
  $ "$TESTDIR/killdaemons.py" hg.pid

verify 7e7d56fe4833 (encoding fallback in branchmap to maintain compatibility with 1.3.x)

  $ cat <<EOF > oldhg
  > import sys
  > from mercurial import ui, hg, commands
  > 
  > class StdoutWrapper(object):
  >     def __init__(self, stdout):
  >         self._file = stdout
  > 
  >     def write(self, data):
  >         if data == '47\n':
  >             # latin1 encoding is one %xx (3 bytes) shorter
  >             data = '44\n'
  >         elif data.startswith('%C3%A6 '):
  >             # translate to latin1 encoding
  >             data = '%%E6 %s' % data[7:]
  >         self._file.write(data)
  > 
  >     def __getattr__(self, name):
  >         return getattr(self._file, name)
  > 
  > sys.stdout = StdoutWrapper(sys.stdout)
  > sys.stderr = StdoutWrapper(sys.stderr)
  > 
  > myui = ui.ui()
  > repo = hg.repository(myui, 'a')
  > commands.serve(myui, repo, stdio=True, cmdserver=False)
  > EOF
  $ echo baz >> b/foo
  $ hg -R b ci -m baz
  $ hg push -R b -e 'python oldhg' ssh://dummy/ --encoding latin1
  pushing to ssh://dummy/
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 1 changes to 1 files