view tests/test-rebuildstate.t @ 47120:7109a38830c9

dirstate-tree: Fold "tracked descendants" counter update in main walk

For the purpose of implementing `has_tracked_dir` (which means "has tracked
descendants) without an expensive sub-tree traversal, we maintaing a counter
of tracked descendants on each "directory" node of the tree-shaped dirstate.

Before this changeset, mutating or inserting a node at a given path would
involve:

* Walking the tree from root through ancestors to find the node or the spot
  where to insert it
* Looking at the previous node if any to decide what counter update is needed
* Performing any node mutation
* Walking the tree *again* to update counters in ancestor nodes

When profiling `hg status` on a large repo, this second walk takes times
while loading a the dirstate from disk.

It turns out we have enough information to decide before he first tree walk
what counter update is needed. This changeset merges the two walks, gaining
~10% of the total time for `hg update` (in the same hyperfine benchmark as
the previous changeset).

---

Profiling was done by compiling with this `.cargo/config`:

    [profile.release]
    debug = true

then running with:

    py-spy record -r 500 -n -o /tmp/hg.json --format speedscope -- \
    ./hg status -R $REPO --config experimental.dirstate-tree.in-memory=1

then visualizing the recorded JSON file in https://www.speedscope.app/

Differential Revision: https://phab.mercurial-scm.org/D10554

  $ cat > adddrop.py <<EOF
  > from mercurial import registrar
  > cmdtable = {}
  > command = registrar.command(cmdtable)
  > @command(b'debugadddrop',
  >   [(b'', b'drop', False, b'drop file from dirstate', b'FILE'),
  >    (b'', b'normal-lookup', False, b'add file to dirstate', b'FILE')],
  >     b'hg debugadddrop')
  > def debugadddrop(ui, repo, *pats, **opts):
  >   '''Add or drop unnamed arguments to or from the dirstate'''
  >   drop = opts.get('drop')
  >   nl = opts.get('normal_lookup')
  >   if nl and drop:
  >       raise error.Abort('drop and normal-lookup are mutually exclusive')
  >   wlock = repo.wlock()
  >   try:
  >     for file in pats:
  >       if opts.get('normal_lookup'):
  >         repo.dirstate.normallookup(file)
  >       else:
  >         repo.dirstate.drop(file)
  > 
  >     repo.dirstate.write(repo.currenttransaction())
  >   finally:
  >     wlock.release()
  > EOF

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "debugadddrop=`pwd`/adddrop.py" >> $HGRCPATH

basic test for hg debugrebuildstate

  $ hg init repo
  $ cd repo

  $ touch foo bar
  $ hg ci -Am 'add foo bar'
  adding bar
  adding foo

  $ touch baz
  $ hg add baz
  $ hg rm bar

  $ hg debugrebuildstate

state dump after

  $ hg debugstate --no-dates | sort
  n   0         -1 unset               bar
  n   0         -1 unset               foo

  $ hg debugadddrop --normal-lookup file1 file2
  $ hg debugadddrop --drop bar
  $ hg debugadddrop --drop
  $ hg debugstate --no-dates
  n   0         -1 unset               file1
  n   0         -1 unset               file2
  n   0         -1 unset               foo
  $ hg debugrebuildstate

status

  $ hg st -A
  ! bar
  ? baz
  C foo

Test debugdirstate --minimal where a file is not in parent manifest
but in the dirstate
  $ touch foo bar qux
  $ hg add qux
  $ hg remove bar
  $ hg status -A
  A qux
  R bar
  ? baz
  C foo
  $ hg debugadddrop --normal-lookup baz
  $ hg debugdirstate --no-dates
  r   0          0 * bar (glob)
  n   0         -1 * baz (glob)
  n 644          0 * foo (glob)
  a   0         -1 * qux (glob)
  $ hg debugrebuilddirstate --minimal
  $ hg debugdirstate --no-dates
  r   0          0 * bar (glob)
  n 644          0 * foo (glob)
  a   0         -1 * qux (glob)
  $ hg status -A
  A qux
  R bar
  ? baz
  C foo

Test debugdirstate --minimal where file is in the parent manifest but not the
dirstate
  $ hg manifest
  bar
  foo
  $ hg status -A
  A qux
  R bar
  ? baz
  C foo
  $ hg debugdirstate --no-dates
  r   0          0 * bar (glob)
  n 644          0 * foo (glob)
  a   0         -1 * qux (glob)
  $ hg debugadddrop --drop foo
  $ hg debugdirstate --no-dates
  r   0          0 * bar (glob)
  a   0         -1 * qux (glob)
  $ hg debugrebuilddirstate --minimal
  $ hg debugdirstate --no-dates
  r   0          0 * bar (glob)
  n   0         -1 * foo (glob)
  a   0         -1 * qux (glob)
  $ hg status -A
  A qux
  R bar
  ? baz
  C foo