view tests/test-bisect3.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

# Here we create a simple DAG which has just enough of the required
# topology to test all the bisection status labels:
#
#           13--14
#          /
#   0--1--2--3---------9--10--11--12
#       \             /
#        4--5--6--7--8


  $ hg init

  $ echo '0' >a
  $ hg add a
  $ hg ci -u test -d '0 0' -m '0'
  $ echo '1' >a
  $ hg ci -u test -d '1 0' -m '1'

branch 2-3

  $ echo '2' >b
  $ hg add b
  $ hg ci -u test -d '2 0' -m '2'
  $ echo '3' >b
  $ hg ci -u test -d '3 0' -m '3'

branch 4-8

  $ hg up -r 1
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo '4' >c
  $ hg add c
  $ hg ci -u test -d '4 0' -m '4'
  created new head
  $ echo '5' >c
  $ hg ci -u test -d '5 0' -m '5'
  $ echo '6' >c
  $ hg ci -u test -d '6 0' -m '6'
  $ echo '7' >c
  $ hg ci -u test -d '7 0' -m '7'
  $ echo '8' >c
  $ hg ci -u test -d '8 0' -m '8'

merge

  $ hg merge -r 3
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -u test -d '9 0' -m '9=8+3'

  $ echo '10' >a
  $ hg ci -u test -d '10 0' -m '10'
  $ echo '11' >a
  $ hg ci -u test -d '11 0' -m '11'
  $ echo '12' >a
  $ hg ci -u test -d '12 0' -m '12'

unrelated branch

  $ hg up -r 3
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo '13' >d
  $ hg add d
  $ hg ci -u test -d '13 0' -m '13'
  created new head
  $ echo '14' >d
  $ hg ci -u test -d '14 0' -m '14'

mark changesets

  $ hg bisect --reset
  $ hg bisect --good 4
  $ hg bisect --good 6
  $ hg bisect --bad 12
  Testing changeset 9:2197c557e14c (6 changesets remaining, ~2 tests)
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg bisect --bad 10
  Testing changeset 8:e74a86251f58 (4 changesets remaining, ~2 tests)
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg bisect --skip 7
  Testing changeset 8:e74a86251f58 (4 changesets remaining, ~2 tests)
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved

test template

  $ hg log --template '{rev}:{node|short} {bisect}\n'
  14:cbf2f3105bbf 
  13:e07efca37c43 
  12:98c6b56349c0 bad
  11:03f491376e63 bad (implicit)
  10:c012b15e2409 bad
  9:2197c557e14c untested
  8:e74a86251f58 untested
  7:a5f87041c899 skipped
  6:7d997bedcd8d good
  5:2dd1875f1028 good (implicit)
  4:2a1daef14cd4 good
  3:8417d459b90c ignored
  2:e1355ee1f23e ignored
  1:ce7c85e06a9f good (implicit)
  0:b4e73ffab476 good (implicit)
  $ hg log --template '{bisect|shortbisect} {rev}:{node|short}\n'
    14:cbf2f3105bbf
    13:e07efca37c43
  B 12:98c6b56349c0
  B 11:03f491376e63
  B 10:c012b15e2409
  U 9:2197c557e14c
  U 8:e74a86251f58
  S 7:a5f87041c899
  G 6:7d997bedcd8d
  G 5:2dd1875f1028
  G 4:2a1daef14cd4
  I 3:8417d459b90c
  I 2:e1355ee1f23e
  G 1:ce7c85e06a9f
  G 0:b4e73ffab476

test style

  $ hg log --style bisect
  changeset:   14:cbf2f3105bbf
  bisect:      
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:14 1970 +0000
  summary:     14
  
  changeset:   13:e07efca37c43
  bisect:      
  parent:      3:8417d459b90c
  user:        test
  date:        Thu Jan 01 00:00:13 1970 +0000
  summary:     13
  
  changeset:   12:98c6b56349c0
  bisect:      bad
  user:        test
  date:        Thu Jan 01 00:00:12 1970 +0000
  summary:     12
  
  changeset:   11:03f491376e63
  bisect:      bad (implicit)
  user:        test
  date:        Thu Jan 01 00:00:11 1970 +0000
  summary:     11
  
  changeset:   10:c012b15e2409
  bisect:      bad
  user:        test
  date:        Thu Jan 01 00:00:10 1970 +0000
  summary:     10
  
  changeset:   9:2197c557e14c
  bisect:      untested
  parent:      8:e74a86251f58
  parent:      3:8417d459b90c
  user:        test
  date:        Thu Jan 01 00:00:09 1970 +0000
  summary:     9=8+3
  
  changeset:   8:e74a86251f58
  bisect:      untested
  user:        test
  date:        Thu Jan 01 00:00:08 1970 +0000
  summary:     8
  
  changeset:   7:a5f87041c899
  bisect:      skipped
  user:        test
  date:        Thu Jan 01 00:00:07 1970 +0000
  summary:     7
  
  changeset:   6:7d997bedcd8d
  bisect:      good
  user:        test
  date:        Thu Jan 01 00:00:06 1970 +0000
  summary:     6
  
  changeset:   5:2dd1875f1028
  bisect:      good (implicit)
  user:        test
  date:        Thu Jan 01 00:00:05 1970 +0000
  summary:     5
  
  changeset:   4:2a1daef14cd4
  bisect:      good
  parent:      1:ce7c85e06a9f
  user:        test
  date:        Thu Jan 01 00:00:04 1970 +0000
  summary:     4
  
  changeset:   3:8417d459b90c
  bisect:      ignored
  user:        test
  date:        Thu Jan 01 00:00:03 1970 +0000
  summary:     3
  
  changeset:   2:e1355ee1f23e
  bisect:      ignored
  user:        test
  date:        Thu Jan 01 00:00:02 1970 +0000
  summary:     2
  
  changeset:   1:ce7c85e06a9f
  bisect:      good (implicit)
  user:        test
  date:        Thu Jan 01 00:00:01 1970 +0000
  summary:     1
  
  changeset:   0:b4e73ffab476
  bisect:      good (implicit)
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     0
  
  $ hg log --quiet --style bisect
    14:cbf2f3105bbf
    13:e07efca37c43
  B 12:98c6b56349c0
  B 11:03f491376e63
  B 10:c012b15e2409
  U 9:2197c557e14c
  U 8:e74a86251f58
  S 7:a5f87041c899
  G 6:7d997bedcd8d
  G 5:2dd1875f1028
  G 4:2a1daef14cd4
  I 3:8417d459b90c
  I 2:e1355ee1f23e
  G 1:ce7c85e06a9f
  G 0:b4e73ffab476

  $ hg --config extensions.color= --color=debug log --quiet --style bisect
  [log.bisect| ] 14:cbf2f3105bbf
  [log.bisect| ] 13:e07efca37c43
  [log.bisect bisect.bad|B] 12:98c6b56349c0
  [log.bisect bisect.bad|B] 11:03f491376e63
  [log.bisect bisect.bad|B] 10:c012b15e2409
  [log.bisect bisect.untested|U] 9:2197c557e14c
  [log.bisect bisect.untested|U] 8:e74a86251f58
  [log.bisect bisect.skipped|S] 7:a5f87041c899
  [log.bisect bisect.good|G] 6:7d997bedcd8d
  [log.bisect bisect.good|G] 5:2dd1875f1028
  [log.bisect bisect.good|G] 4:2a1daef14cd4
  [log.bisect bisect.ignored|I] 3:8417d459b90c
  [log.bisect bisect.ignored|I] 2:e1355ee1f23e
  [log.bisect bisect.good|G] 1:ce7c85e06a9f
  [log.bisect bisect.good|G] 0:b4e73ffab476