view tests/test-histedit-non-commute.t @ 44363:f7459da77f23

nodemap: introduce an option to use mmap to read the nodemap mapping

The performance and memory benefit is much greater if we don't have to copy all
the data in memory for each information. So we introduce an option (on by
default) to read the data using mmap.

This changeset is the last one definition the API for index support nodemap
data. (they have to be able to use the mmaping).

Below are some benchmark comparing the best we currently have in 5.3 with the
final step of this series (using the persistent nodemap implementation in
Rust). The benchmark run `hg perfindex` with various revset and the following
variants:

Before:

 * do not use the persistent nodemap
 * use the CPython implementation of the index for nodemap
 * use mmapping of the changelog index

After:

 * use the MixedIndex Rust code, with the NodeTree object for nodemap access
   (still in review)
 * use the persistent nodemap data from disk
 * access the persistent nodemap data through mmap
 * use mmapping of the changelog index

The persistent nodemap greatly speed up  most operation on very large
repositories. Some of the previously very fast lookup end up a bit slower because
the persistent nodemap has to be setup. However the absolute slowdown is very
small and won't matters in the big picture.

Here are some numbers (in seconds) for the reference copy of mozilla-try:

Revset            Before   After     abs-change speedup

-10000:           0.004622 0.005532   0.000910  ×   0.83
-10:              0.000050 0.000132   0.000082  ×   0.37
tip               0.000052 0.000085   0.000033  ×   0.61
0 + (-10000:)     0.028222 0.005337  -0.022885  ×   5.29
0                 0.023521 0.000084  -0.023437  × 280.01
(-10000:) + 0     0.235539 0.005308  -0.230231  ×  44.37
(-10:) + :9       0.232883 0.000180  -0.232703  ×1293.79
(-10000:) + (:99) 0.238735 0.005358  -0.233377  ×  44.55
:99 + (-10000:)   0.317942 0.005593  -0.312349  ×  56.84
:9 + (-10:)       0.313372 0.000179  -0.313193  ×1750.68
:9                0.316450 0.000143  -0.316307  ×2212.93


On smaller repositories, the cost of nodemap related operation is not as big, so
the win is much more modest. Yet it helps shaving a handful of millisecond here
and there.

Here are some numbers (in seconds) for the reference copy of mercurial:

Revset            Before   After     abs-change speedup
-10:              0.000065 0.000097   0.000032  × 0.67
tip               0.000063 0.000078   0.000015  × 0.80
0                 0.000561 0.000079  -0.000482  × 7.10
-10000:           0.004609 0.003648  -0.000961  × 1.26
0 + (-10000:)     0.005023 0.003715  -0.001307  × 1.35
(-10:) + :9       0.002187 0.000108  -0.002079  ×20.25
(-10000:) + 0     0.006252 0.003716  -0.002536  × 1.68
(-10000:) + (:99) 0.006367 0.003707  -0.002660  × 1.71
:9 + (-10:)       0.003846 0.000110  -0.003736  ×34.96
:9                0.003854 0.000099  -0.003755  ×38.92
:99 + (-10000:)   0.007644 0.003778  -0.003866  × 2.02

Differential Revision: https://phab.mercurial-scm.org/D7894

  $ . "$TESTDIR/histedit-helpers.sh"

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > histedit=
  > EOF

  $ initrepo ()
  > {
  >     hg init $1
  >     cd $1
  >     for x in a b c d e f ; do
  >         echo $x$x$x$x$x > $x
  >         hg add $x
  >     done
  >     hg ci -m 'Initial commit'
  >     for x in a b c d e f ; do
  >         echo $x > $x
  >         hg ci -m $x
  >     done
  >     echo 'I can haz no commute' > e
  >     hg ci -m 'does not commute with e'
  >     cd ..
  > }

  $ initrepo r1
  $ cd r1

Initial generation of the command files

  $ EDITED="$TESTTMP/editedhistory"
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 3 >> $EDITED
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 4 >> $EDITED
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 7 >> $EDITED
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 5 >> $EDITED
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 6 >> $EDITED
  $ cat $EDITED
  pick 65a9a84f33fd 3 c
  pick 00f1c5383965 4 d
  pick 39522b764e3d 7 does not commute with e
  pick 7b4e2f4b7bcd 5 e
  pick 500cac37a696 6 f

log before edit
  $ hg log --graph
  @  changeset:   7:39522b764e3d
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     does not commute with e
  |
  o  changeset:   6:500cac37a696
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     f
  |
  o  changeset:   5:7b4e2f4b7bcd
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     e
  |
  o  changeset:   4:00f1c5383965
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     d
  |
  o  changeset:   3:65a9a84f33fd
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     c
  |
  o  changeset:   2:da6535b52e45
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     b
  |
  o  changeset:   1:c1f09da44841
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     a
  |
  o  changeset:   0:1715188a53c7
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     Initial commit
  

edit the history
  $ hg histedit 3 --commands $EDITED 2>&1 | fixbundle
  merging e
  warning: conflicts while merging e! (edit, then use 'hg resolve --mark')
  Fix up the change (pick 39522b764e3d)
  (hg histedit --continue to resume)

abort the edit
  $ hg histedit --abort 2>&1 | fixbundle
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved


second edit set

  $ hg log --graph
  @  changeset:   7:39522b764e3d
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     does not commute with e
  |
  o  changeset:   6:500cac37a696
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     f
  |
  o  changeset:   5:7b4e2f4b7bcd
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     e
  |
  o  changeset:   4:00f1c5383965
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     d
  |
  o  changeset:   3:65a9a84f33fd
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     c
  |
  o  changeset:   2:da6535b52e45
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     b
  |
  o  changeset:   1:c1f09da44841
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     a
  |
  o  changeset:   0:1715188a53c7
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     Initial commit
  

edit the history
  $ hg histedit 3 --commands $EDITED 2>&1 | fixbundle
  merging e
  warning: conflicts while merging e! (edit, then use 'hg resolve --mark')
  Fix up the change (pick 39522b764e3d)
  (hg histedit --continue to resume)

fix up
  $ echo 'I can haz no commute' > e
  $ hg resolve --mark e
  (no more unresolved files)
  continue: hg histedit --continue
  $ hg histedit --continue 2>&1 | fixbundle
  merging e
  warning: conflicts while merging e! (edit, then use 'hg resolve --mark')
  Fix up the change (pick 7b4e2f4b7bcd)
  (hg histedit --continue to resume)
We forcibly enable curses here so we can verify that continuing works
with curses enabled.
  $ hg histedit --continue --config ui.interactive=true \
  >   --config ui.interface=curses 2>&1 | fixbundle
  abort: unresolved merge conflicts (see 'hg help resolve')

This failure is caused by 7b4e2f4b7bcd "e" not rebasing the non commutative
former children.

just continue this time
  $ hg revert -r 'p1()' e
make sure the to-be-empty commit doesn't screw up the state (issue5545)
  $ hg histedit --continue 2>&1 | fixbundle
  abort: unresolved merge conflicts (see 'hg help resolve')
  $ hg resolve --mark e
  (no more unresolved files)
  continue: hg histedit --continue
  $ hg histedit --continue 2>&1 | fixbundle
  7b4e2f4b7bcd: skipping changeset (no changes)

log after edit
  $ hg log --graph
  @  changeset:   6:7efe1373e4bc
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     f
  |
  o  changeset:   5:e334d87a1e55
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     does not commute with e
  |
  o  changeset:   4:00f1c5383965
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     d
  |
  o  changeset:   3:65a9a84f33fd
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     c
  |
  o  changeset:   2:da6535b52e45
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     b
  |
  o  changeset:   1:c1f09da44841
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     a
  |
  o  changeset:   0:1715188a53c7
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     Initial commit
  

start over

  $ cd ..

  $ initrepo r2
  $ cd r2
  $ rm $EDITED
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 3 >> $EDITED
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 4 >> $EDITED
  $ hg log --template 'mess {node|short} {rev} {desc}\n' -r 7 >> $EDITED
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 5 >> $EDITED
  $ hg log --template 'pick {node|short} {rev} {desc}\n' -r 6 >> $EDITED
  $ cat $EDITED
  pick 65a9a84f33fd 3 c
  pick 00f1c5383965 4 d
  mess 39522b764e3d 7 does not commute with e
  pick 7b4e2f4b7bcd 5 e
  pick 500cac37a696 6 f

edit the history, this time with a fold action
  $ hg histedit 3 --commands $EDITED 2>&1 | fixbundle
  merging e
  warning: conflicts while merging e! (edit, then use 'hg resolve --mark')
  Fix up the change (mess 39522b764e3d)
  (hg histedit --continue to resume)

  $ echo 'I can haz no commute' > e
  $ hg resolve --mark e
  (no more unresolved files)
  continue: hg histedit --continue
  $ hg histedit --continue 2>&1 | fixbundle
  merging e
  warning: conflicts while merging e! (edit, then use 'hg resolve --mark')
  Fix up the change (pick 7b4e2f4b7bcd)
  (hg histedit --continue to resume)
second edit also fails, but just continue
  $ hg revert -r 'p1()' e
  $ hg resolve --mark e
  (no more unresolved files)
  continue: hg histedit --continue
  $ hg histedit --continue 2>&1 | fixbundle
  7b4e2f4b7bcd: skipping changeset (no changes)

post message fix
  $ hg log --graph
  @  changeset:   6:7efe1373e4bc
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     f
  |
  o  changeset:   5:e334d87a1e55
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     does not commute with e
  |
  o  changeset:   4:00f1c5383965
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     d
  |
  o  changeset:   3:65a9a84f33fd
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     c
  |
  o  changeset:   2:da6535b52e45
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     b
  |
  o  changeset:   1:c1f09da44841
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     a
  |
  o  changeset:   0:1715188a53c7
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     Initial commit
  

  $ cd ..