view tests/test-rebase-detach.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

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > rebase=
  > 
  > [alias]
  > tglog = log -G --template "{rev}: {node|short} '{desc}'\n"
  > 
  > [extensions]
  > drawdag=$TESTDIR/drawdag.py
  > EOF

Rebasing D onto B detaching from C (one commit):

  $ hg init a1
  $ cd a1

  $ hg debugdrawdag <<EOF
  > D
  > |
  > C B
  > |/
  > A
  > EOF
  $ hg phase --force --secret D

  $ hg rebase -s D -d B
  rebasing 3:e7b3f00ed42e "D" (D tip)
  saved backup bundle to $TESTTMP/a1/.hg/strip-backup/e7b3f00ed42e-6f368371-rebase.hg

  $ hg log -G --template "{rev}:{phase} '{desc}' {branches}\n"
  o  3:secret 'D'
  |
  | o  2:draft 'C'
  | |
  o |  1:draft 'B'
  |/
  o  0:draft 'A'
  
  $ hg manifest --rev tip
  A
  B
  D

  $ cd ..


Rebasing D onto B detaching from C (two commits):

  $ hg init a2
  $ cd a2

  $ hg debugdrawdag <<EOF
  > E
  > |
  > D
  > |
  > C B
  > |/
  > A
  > EOF

  $ hg rebase -s D -d B
  rebasing 3:e7b3f00ed42e "D" (D)
  rebasing 4:69a34c08022a "E" (E tip)
  saved backup bundle to $TESTTMP/a2/.hg/strip-backup/e7b3f00ed42e-a2ec7cea-rebase.hg

  $ hg tglog
  o  4: ee79e0744528 'E'
  |
  o  3: 10530e1d72d9 'D'
  |
  | o  2: dc0947a82db8 'C'
  | |
  o |  1: 112478962961 'B'
  |/
  o  0: 426bada5c675 'A'
  
  $ hg manifest --rev tip
  A
  B
  D
  E

  $ cd ..

Rebasing C onto B using detach (same as not using it):

  $ hg init a3
  $ cd a3

  $ hg debugdrawdag <<EOF
  > D
  > |
  > C B
  > |/
  > A
  > EOF

  $ hg rebase -s C -d B
  rebasing 2:dc0947a82db8 "C" (C)
  rebasing 3:e7b3f00ed42e "D" (D tip)
  saved backup bundle to $TESTTMP/a3/.hg/strip-backup/dc0947a82db8-b8481714-rebase.hg

  $ hg tglog
  o  3: 7375f3dbfb0f 'D'
  |
  o  2: bbfdd6cb49aa 'C'
  |
  o  1: 112478962961 'B'
  |
  o  0: 426bada5c675 'A'
  
  $ hg manifest --rev tip
  A
  B
  C
  D

  $ cd ..


Rebasing D onto B detaching from C and collapsing:

  $ hg init a4
  $ cd a4

  $ hg debugdrawdag <<EOF
  > E
  > |
  > D
  > |
  > C B
  > |/
  > A
  > EOF
  $ hg phase --force --secret E

  $ hg rebase --collapse -s D -d B
  rebasing 3:e7b3f00ed42e "D" (D)
  rebasing 4:69a34c08022a "E" (E tip)
  saved backup bundle to $TESTTMP/a4/.hg/strip-backup/e7b3f00ed42e-a2ec7cea-rebase.hg

  $ hg  log -G --template "{rev}:{phase} '{desc}' {branches}\n"
  o  3:secret 'Collapsed revision
  |  * D
  |  * E'
  | o  2:draft 'C'
  | |
  o |  1:draft 'B'
  |/
  o  0:draft 'A'
  
  $ hg manifest --rev tip
  A
  B
  D
  E

  $ cd ..

Rebasing across null as ancestor
  $ hg init a5
  $ cd a5

  $ hg debugdrawdag <<EOF
  > E
  > |
  > D
  > |
  > C
  > |
  > A B
  > EOF

  $ hg rebase -s C -d B
  rebasing 2:dc0947a82db8 "C" (C)
  rebasing 3:e7b3f00ed42e "D" (D)
  rebasing 4:69a34c08022a "E" (E tip)
  saved backup bundle to $TESTTMP/a5/.hg/strip-backup/dc0947a82db8-3eefec98-rebase.hg

  $ hg tglog
  o  4: e3d0c70d606d 'E'
  |
  o  3: e9153d36a1af 'D'
  |
  o  2: a7ac28b870a8 'C'
  |
  o  1: fc2b737bb2e5 'B'
  
  o  0: 426bada5c675 'A'
  
  $ hg rebase -d 1 -s 3
  rebasing 3:e9153d36a1af "D"
  rebasing 4:e3d0c70d606d "E" (tip)
  saved backup bundle to $TESTTMP/a5/.hg/strip-backup/e9153d36a1af-db7388ed-rebase.hg
  $ hg tglog
  o  4: 2c24e540eccd 'E'
  |
  o  3: 73f786ed52ff 'D'
  |
  | o  2: a7ac28b870a8 'C'
  |/
  o  1: fc2b737bb2e5 'B'
  
  o  0: 426bada5c675 'A'
  
  $ cd ..

Verify that target is not selected as external rev (issue3085)

  $ hg init a6
  $ cd a6

  $ hg debugdrawdag <<EOF
  > H
  > | G
  > |/|
  > F E
  > |/
  > A
  > EOF
  $ hg up -q G

  $ echo "I" >> E
  $ hg ci -m "I"
  $ hg tag --local I
  $ hg merge H
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -m "Merge"
  $ echo "J" >> F
  $ hg ci -m "J"
  $ hg tglog
  @  7: c6aaf0d259c0 'J'
  |
  o    6: 0cfbc7e8faaf 'Merge'
  |\
  | o  5: b92d164ad3cb 'I'
  | |
  o |  4: 4ea5b230dea3 'H'
  | |
  | o  3: c6001eacfde5 'G'
  |/|
  o |  2: 8908a377a434 'F'
  | |
  | o  1: 7fb047a69f22 'E'
  |/
  o  0: 426bada5c675 'A'
  
  $ hg rebase -s I -d H --collapse --config ui.merge=internal:other
  rebasing 5:b92d164ad3cb "I" (I)
  rebasing 6:0cfbc7e8faaf "Merge"
  rebasing 7:c6aaf0d259c0 "J" (tip)
  saved backup bundle to $TESTTMP/a6/.hg/strip-backup/b92d164ad3cb-88fd7ab7-rebase.hg

  $ hg tglog
  @  5: 65079693dac4 'Collapsed revision
  |  * I
  |  * Merge
  |  * J'
  o  4: 4ea5b230dea3 'H'
  |
  | o  3: c6001eacfde5 'G'
  |/|
  o |  2: 8908a377a434 'F'
  | |
  | o  1: 7fb047a69f22 'E'
  |/
  o  0: 426bada5c675 'A'
  

  $ hg log --rev tip
  changeset:   5:65079693dac4
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     Collapsed revision
  

  $ cd ..

Ensure --continue restores a correct state (issue3046) and phase:
  $ hg init a7
  $ cd a7

  $ hg debugdrawdag <<EOF
  > C B
  > |/
  > A
  > EOF
  $ hg up -q C
  $ echo 'B2' > B
  $ hg ci -A -m 'B2'
  adding B
  $ hg phase --force --secret .
  $ hg rebase -s . -d B --config ui.merge=internal:merge
  rebasing 3:17b4880d2402 "B2" (tip)
  merging B
  warning: conflicts while merging B! (edit, then use 'hg resolve --mark')
  unresolved conflicts (see hg resolve, then hg rebase --continue)
  [1]
  $ hg resolve --all -t internal:local
  (no more unresolved files)
  continue: hg rebase --continue
  $ hg rebase -c
  rebasing 3:17b4880d2402 "B2" (tip)
  note: not rebasing 3:17b4880d2402 "B2" (tip), its destination already has all its changes
  saved backup bundle to $TESTTMP/a7/.hg/strip-backup/17b4880d2402-1ae1f6cc-rebase.hg
  $ hg  log -G --template "{rev}:{phase} '{desc}' {branches}\n"
  o  2:draft 'C'
  |
  | @  1:draft 'B'
  |/
  o  0:draft 'A'
  

  $ cd ..