view tests/test-debugextensions.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

#if no-extraextensions
  $ hg debugextensions
#endif

  $ debugpath=`pwd`/extwithoutinfos.py

  $ cat > extwithoutinfos.py <<EOF
  > EOF
  $ cat > extwithinfos.py <<EOF
  > testedwith = b'3.0 3.1 3.2.1'
  > buglink = b'https://example.org/bts'
  > EOF

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > histedit=
  > patchbomb=
  > rebase=
  > mq=
  > ext1 = $debugpath
  > ext2 = `pwd`/extwithinfos.py
  > EOF

  $ for extension in $HGTESTEXTRAEXTENSIONS; do
  >     echo "$extension=!" >> $HGRCPATH
  > done

  $ hg debugextensions
  ext1 (untested!)
  ext2 (3.2.1!)
  histedit
  mq
  patchbomb
  rebase

  $ hg debugextensions -v
  ext1
    location: */extwithoutinfos.py* (glob)
    bundled: no
  ext2
    location: */extwithinfos.py* (glob)
    bundled: no
    tested with: 3.0 3.1 3.2.1
    bug reporting: https://example.org/bts
  histedit
    location: */hgext/histedit.py* (glob)
    bundled: yes
  mq
    location: */hgext/mq.py* (glob)
    bundled: yes
  patchbomb
    location: */hgext/patchbomb.py* (glob)
    bundled: yes
  rebase
    location: */hgext/rebase.py* (glob)
    bundled: yes

  $ hg debugextensions -Tjson | sed 's|\\\\|/|g'
  [
   {
    "buglink": "",
    "bundled": false,
    "name": "ext1",
    "source": "*/extwithoutinfos.py*", (glob)
    "testedwith": []
   },
   {
    "buglink": "https://example.org/bts",
    "bundled": false,
    "name": "ext2",
    "source": "*/extwithinfos.py*", (glob)
    "testedwith": ["3.0", "3.1", "3.2.1"]
   },
   {
    "buglink": "",
    "bundled": true,
    "name": "histedit",
    "source": "*/hgext/histedit.py*", (glob)
    "testedwith": []
   },
   {
    "buglink": "",
    "bundled": true,
    "name": "mq",
    "source": "*/hgext/mq.py*", (glob)
    "testedwith": []
   },
   {
    "buglink": "",
    "bundled": true,
    "name": "patchbomb",
    "source": "*/hgext/patchbomb.py*", (glob)
    "testedwith": []
   },
   {
    "buglink": "",
    "bundled": true,
    "name": "rebase",
    "source": "*/hgext/rebase.py*", (glob)
    "testedwith": []
   }
  ]

  $ hg debugextensions -T '{ifcontains("3.1", testedwith, "{name}\n")}'
  ext2
  $ hg debugextensions \
  > -T '{ifcontains("3.2", testedwith, "no substring match: {name}\n")}'