view tests/test-inotify-issue1208.t @ 17970:0b03454abae7

ancestor: faster algorithm for difference of ancestor sets

One of the major reasons rebase is slow in large repositories is
the computation of the detach set: the set of ancestors of the
changesets to rebase not in the destination parent. This is currently
done via a revset that does two walks all the way to the root of
the DAG. Instead of doing that, to find ancestors of a set <revs>
not in another set <common> we walk up the tree in reverse revision
number order, maintaining sets of nodes visited from <revs>, <common>
or both.

For the common case where the sets are close both topologically and
in revision number (relative to repository size), this has been
found to speed up rebase by around 15-20%. When the nodes are farther
apart and the DAG is highly branching, it is harder to say which
would win.

Here's how long computing the detach set takes in a linear repository
with over 400000 changesets, rebasing near tip:

Rebasing across 4 changesets
Revset method: 2.2s
New algorithm: 0.00015s

Rebasing across 250 changesets
Revset method: 2.2s
New algorithm: 0.00069s

Rebasing across 10000 changesets
Revset method: 2.4s
New algorithm: 0.019s

  $ "$TESTDIR/hghave" inotify || exit 80
  $ echo "[extensions]" >> $HGRCPATH
  $ echo "inotify=" >> $HGRCPATH
  $ p="xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
  $ hg init $p
  $ cd $p

fail

  $ ln -sf doesnotexist .hg/inotify.sock
  $ hg st
  abort: inotify-server: cannot start: .hg/inotify.sock is a broken symlink
  inotify-client: could not start inotify server: child process failed to start
  $ hg inserve
  abort: inotify-server: cannot start: .hg/inotify.sock is a broken symlink
  [255]
  $ rm .hg/inotify.sock

inserve

  $ hg inserve -d --pid-file=hg.pid
  $ cat hg.pid >> "$DAEMON_PIDS"

status

  $ hg status
  ? hg.pid

if we try to start twice the server, make sure we get a correct error

  $ hg inserve -d --pid-file=hg2.pid
  abort: inotify-server: cannot start: socket is already bound
  abort: child process failed to start
  [255]
  $ kill `cat hg.pid`

  $ cd ..