view tests/test-bundle2-pushback.t @ 30288:ceddc3d94d74

revlog: inline start() and end() for perf reasons

When I implemented `hg perfrevlogchunks`, one of the things that
stood out was N * _chunk() calls was ~38x slower than 1
_chunks() call. Specifically, on the mozilla-unified repo:

N*_chunk:  0.528997s
1*_chunks: 0.013735s

This repo has 352,097 changesets. So the average time per changeset
comes out to:

N*_chunk:  1.502us
1*_chunks: 0.039us

If you extrapolate these numbers to a repository with 1M changesets,
that comes out to 1.502s versus 0.039s, which is significant.

At these latencies, Python attribute lookups and function calls
matter. So, this patch inlines some code to cut down on that overhead.

The impact of this patch on N*_chunk() calls is clear:

! wall 0.528997 comb 0.520000 user 0.500000 sys 0.020000 (best of 19)
! wall 0.367723 comb 0.370000 user 0.350000 sys 0.020000 (best of 27)

So, we go from ~38x slower to ~27x. A nice improvement. But there's
still a long way to go.

It's worth noting that functionality like revsets perform changelog
lookups one revision at a time. So this code path is worth optimizing.

  $ cat > bundle2.py << EOF
  > """A small extension to test bundle2 pushback parts.
  > Current bundle2 implementation doesn't provide a way to generate those
  > parts, so they must be created by extensions.
  > """
  > from mercurial import bundle2, pushkey, exchange, util
  > def _newhandlechangegroup(op, inpart):
  >     """This function wraps the changegroup part handler for getbundle.
  >     It issues an additional pushkey part to send a new
  >     bookmark back to the client"""
  >     result = bundle2.handlechangegroup(op, inpart)
  >     if 'pushback' in op.reply.capabilities:
  >         params = {'namespace': 'bookmarks',
  >                   'key': 'new-server-mark',
  >                   'old': '',
  >                   'new': 'tip'}
  >         encodedparams = [(k, pushkey.encode(v)) for (k,v) in params.items()]
  >         op.reply.newpart('pushkey', mandatoryparams=encodedparams)
  >     else:
  >         op.reply.newpart('output', data='pushback not enabled')
  >     return result
  > _newhandlechangegroup.params = bundle2.handlechangegroup.params
  > bundle2.parthandlermapping['changegroup'] = _newhandlechangegroup
  > EOF

  $ cat >> $HGRCPATH <<EOF
  > [ui]
  > ssh = python "$TESTDIR/dummyssh"
  > username = nobody <[e-mail]>
  > 
  > [alias]
  > tglog = log -G -T "{desc} [{phase}:{node|short}]"
  > EOF

Set up server repository

  $ hg init server
  $ cd server
  $ echo c0 > f0
  $ hg commit -Am 0
  adding f0

Set up client repository

  $ cd ..
  $ hg clone ssh://user@dummy/server client -q
  $ cd client

Enable extension
  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > bundle2=$TESTTMP/bundle2.py
  > EOF

Without config

  $ cd ../client
  $ echo c1 > f1
  $ hg commit -Am 1
  adding f1
  $ hg push
  pushing to ssh://user@dummy/server
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 1 changes to 1 files
  remote: pushback not enabled
  $ hg bookmark
  no bookmarks set

  $ cd ../server
  $ hg tglog
  o  1 [public:2b9c7234e035]
  |
  @  0 [public:6cee5c8f3e5b]
  



With config

  $ cd ../client
  $ echo '[experimental]' >> .hg/hgrc
  $ echo 'bundle2.pushback = True' >> .hg/hgrc
  $ echo c2 > f2
  $ hg commit -Am 2
  adding f2
  $ hg push
  pushing to ssh://user@dummy/server
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 1 changes to 1 files
  $ hg bookmark
     new-server-mark           2:0a76dfb2e179

  $ cd ../server
  $ hg tglog
  o  2 [public:0a76dfb2e179]
  |
  o  1 [public:2b9c7234e035]
  |
  @  0 [public:6cee5c8f3e5b]