annotate tests/test-lock-badness.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

#require unix-permissions no-root no-windows

Prepare

  $ hg init a
  $ echo a > a/a
  $ hg -R a ci -A -m a
  adding a

  $ hg clone a b
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

Test that raising an exception in the release function doesn't cause the lock to choke

  $ cat > testlock.py << EOF
  > from mercurial import error, registrar
  > 
  > cmdtable = {}
  > command = registrar.command(cmdtable)
  > 
  > def acquiretestlock(repo, releaseexc):
  >     def unlock():
  >         if releaseexc:
  >             raise error.Abort(b'expected release exception')
  >     l = repo._lock(repo.vfs, b'testlock', False, unlock, None, b'test lock')
  >     return l
  > 
  > @command(b'testlockexc')
  > def testlockexc(ui, repo):
  >     testlock = acquiretestlock(repo, True)
  >     try:
  >         testlock.release()
  >     finally:
  >         try:
  >             testlock = acquiretestlock(repo, False)
  >         except error.LockHeld:
  >             raise error.Abort(b'lockfile on disk even after releasing!')
  >         testlock.release()
  > EOF
  $ cat >> $HGRCPATH << EOF
  > [extensions]
  > testlock=$TESTTMP/testlock.py
  > EOF

  $ hg -R b testlockexc
  abort: expected release exception
  [255]

One process waiting for another

  $ cat > hooks.py << EOF
  > import time
  > def sleepone(**x): time.sleep(1)
  > def sleephalf(**x): time.sleep(0.5)
  > EOF
  $ echo b > b/b
  $ hg -R b ci -A -m b --config hooks.precommit="python:`pwd`/hooks.py:sleepone" > stdout &
  $ hg -R b up -q --config ui.timeout.warn=0 --config hooks.pre-update="python:`pwd`/hooks.py:sleephalf" \
  > > preup-stdout 2>preup-stderr
  $ wait
  $ cat preup-stdout
  $ cat preup-stderr
  waiting for lock on working directory of b held by process '*' on host '*' (glob)
  got lock after * seconds (glob)
  $ cat stdout
  adding b

On processs waiting on another, warning after a long time.

  $ echo b > b/c
  $ hg -R b ci -A -m b --config hooks.precommit="python:`pwd`/hooks.py:sleepone" > stdout &
  $ hg -R b up -q --config hooks.pre-update="python:`pwd`/hooks.py:sleephalf" \
  > --config ui.timeout.warn=250 \
  > > preup-stdout 2>preup-stderr
  $ wait
  $ cat preup-stdout
  $ cat preup-stderr
  $ cat stdout
  adding c

On processs waiting on another, warning disabled.

  $ echo b > b/d
  $ hg -R b ci -A -m b --config hooks.precommit="python:`pwd`/hooks.py:sleepone" > stdout &
  $ hg -R b up -q --config hooks.pre-update="python:`pwd`/hooks.py:sleephalf" \
  > --config ui.timeout.warn=-1 \
  > > preup-stdout 2>preup-stderr
  $ wait
  $ cat preup-stdout
  $ cat preup-stderr
  $ cat stdout
  adding d

check we still print debug output

On processs waiting on another, warning after a long time (debug output on)

  $ echo b > b/e
  $ hg -R b ci -A -m b --config hooks.precommit="python:`pwd`/hooks.py:sleepone" > stdout &
  $ hg -R b up --config hooks.pre-update="python:`pwd`/hooks.py:sleephalf" \
  > --config ui.timeout.warn=250 --debug\
  > > preup-stdout 2>preup-stderr
  $ wait
  $ cat preup-stdout
  calling hook pre-update: hghook_pre-update.sleephalf
  waiting for lock on working directory of b held by process '*' on host '*' (glob)
  got lock after * seconds (glob)
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cat preup-stderr
  $ cat stdout
  adding e

On processs waiting on another, warning disabled, (debug output on)

  $ echo b > b/f
  $ hg -R b ci -A -m b --config hooks.precommit="python:`pwd`/hooks.py:sleepone" > stdout &
  $ hg -R b up --config hooks.pre-update="python:`pwd`/hooks.py:sleephalf" \
  > --config ui.timeout.warn=-1 --debug\
  > > preup-stdout 2>preup-stderr
  $ wait
  $ cat preup-stdout
  calling hook pre-update: hghook_pre-update.sleephalf
  waiting for lock on working directory of b held by process '*' on host '*' (glob)
  got lock after * seconds (glob)
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cat preup-stderr
  $ cat stdout
  adding f

Pushing to a local read-only repo that can't be locked

  $ chmod 100 a/.hg/store

  $ hg -R b push a
  pushing to a
  searching for changes
  abort: could not lock repository a: Permission denied
  [20]

  $ chmod 700 a/.hg/store