view tests/test-simple-update.t @ 42743:8c9a6adec67a

rust-discovery: using the children cache in add_missing

The DAG range computation often needs to get back to very old
revisions, and turns out to be disproportionately long, given
that the end goal is to remove the descendents of the given
missing revisons from the undecided set.

The fast iteration capabilities available in the Rust case make
it possible to avoid the DAG range entirely, at the cost of
precomputing the children cache, and to simply iterate on
children of the given missing revisions.

This is a case where staying on the same side of the interface
between the two languages has clear benefits.

On discoveries with initial undecided sets
small enough to bypass sampling entirely, the total cost of
computing the children cache and the subsequent iteration
becomes better than the Python + C counterpart, which relies on
reachableroots2.

For example, on a repo with more than one million revisions with
an initial undecided set of 11 elements, we get these figures:

Rust version with simple iteration
  addcommons: 57.287us
  first undecided computation: 184.278334ms
  first children cache computation: 131.056us
  addmissings iteration: 42.766us
  first addinfo total: 185.24 ms

Python + C version
  first addcommons: 0.29 ms
  addcommons 0.21 ms
  first undecided computation 191.35 ms
  addmissings 45.75 ms
  first addinfo total: 237.77 ms

On discoveries with large undecided sets, the initial price paid
makes the first addinfo slower than the Python + C version,
but that's more than compensated by the gain in sampling and
subsequent iterations.
Here's an extreme example with an undecided set of a million revisions:

Rust version:
  first undecided computation: 293.842629ms
  first children cache computation: 407.911297ms
  addmissings iteration: 34.312869ms
  first addinfo total: 776.02 ms
  taking initial sample
  query 2: sampling time: 1318.38 ms
  query 2; still undecided: 1005013, sample size is: 200
  addmissings: 143.062us

Python + C version:
  first undecided computation 298.13 ms
  addmissings 80.13 ms
  first addinfo total: 399.62 ms
  taking initial sample
  query 2: sampling time: 3957.23 ms
  query 2; still undecided: 1005013, sample size is: 200
  addmissings 52.88 ms

Differential Revision: https://phab.mercurial-scm.org/D6428

  $ hg init test
  $ cd test
  $ echo foo>foo
  $ hg addremove
  adding foo
  $ hg commit -m "1"

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 1 changesets with 1 changes to 1 files

  $ hg clone . ../branch
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd ../branch
  $ hg co
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo bar>>foo
  $ hg commit -m "2"

  $ cd ../test

  $ hg pull ../branch
  pulling from ../branch
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  new changesets 30aff43faee1
  1 local changesets published
  (run 'hg update' to get a working copy)

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 2 changesets with 2 changes to 1 files

  $ hg co
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ cat foo
  foo
  bar

  $ hg manifest --debug
  6f4310b00b9a147241b071a60c28a650827fb03d 644   foo

update to rev 0 with a date

  $ hg upd -d foo 0
  abort: you can't specify a revision and a date
  [255]

update to default destination (with empty revspec)

  $ hg update -q null
  $ hg update
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg id
  30aff43faee1 tip

  $ hg update -q null
  $ hg update -r ''
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg id
  30aff43faee1 tip

  $ hg update -q null
  $ hg update ''
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg id
  30aff43faee1 tip

  $ cd ..

update with worker processes

#if no-windows

  $ cat <<EOF > forceworker.py
  > from mercurial import extensions, worker
  > def nocost(orig, ui, costperop, nops, threadsafe=True):
  >     return worker._numworkers(ui) > 1
  > def uisetup(ui):
  >     extensions.wrapfunction(worker, 'worthwhile', nocost)
  > EOF

  $ hg init worker
  $ cd worker
  $ cat <<EOF >> .hg/hgrc
  > [extensions]
  > forceworker = $TESTTMP/forceworker.py
  > [worker]
  > numcpus = 4
  > EOF
  $ for i in `"$PYTHON" $TESTDIR/seq.py 1 100`; do
  >   echo $i > $i
  > done
  $ hg ci -qAm 'add 100 files'

  $ hg update null
  0 files updated, 0 files merged, 100 files removed, 0 files unresolved
  $ hg update -v | grep 100
  getting 100
  100 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg status

  $ cd ..

#endif