view tests/test-narrow-clone-nonlinear.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

Testing narrow clones when changesets modifying a matching file exist on
multiple branches

  $ . "$TESTDIR/narrow-library.sh"

  $ hg init master
  $ cd master
  $ cat >> .hg/hgrc <<EOF
  > [narrow]
  > serveellipses=True
  > EOF

  $ hg branch default
  marked working directory as branch default
  (branches are permanent and global, did you want a bookmark?)
  $ for x in `$TESTDIR/seq.py 10`; do
  >   echo $x > "f$x"
  >   hg add "f$x"
  >   hg commit -m "Add $x"
  > done

  $ hg branch release-v1
  marked working directory as branch release-v1
  (branches are permanent and global, did you want a bookmark?)
  $ hg commit -m "Start release for v1"

  $ hg update default
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ for x in `$TESTDIR/seq.py 10`; do
  >   echo "$x v2" > "f$x"
  >   hg commit -m "Update $x to v2"
  > done

  $ hg update release-v1
  10 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg branch release-v1
  marked working directory as branch release-v1
  $ for x in `$TESTDIR/seq.py 1 5`; do
  >   echo "$x v1 hotfix" > "f$x"
  >   hg commit -m "Hotfix $x in v1"
  > done

  $ hg update default
  10 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg branch release-v2
  marked working directory as branch release-v2
  $ hg commit -m "Start release for v2"

  $ hg update default
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg branch default
  marked working directory as branch default
  $ for x in `$TESTDIR/seq.py 10`; do
  >   echo "$x v3" > "f$x"
  >   hg commit -m "Update $x to v3"
  > done

  $ hg update release-v2
  10 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg branch release-v2
  marked working directory as branch release-v2
  $ for x in `$TESTDIR/seq.py 4 9`; do
  >   echo "$x v2 hotfix" > "f$x"
  >   hg commit -m "Hotfix $x in v2"
  > done

  $ hg heads -T '{rev} <- {p1rev} ({branch}): {desc}\n'
  42 <- 41 (release-v2): Hotfix 9 in v2
  36 <- 35 (default): Update 10 to v3
  25 <- 24 (release-v1): Hotfix 5 in v1

  $ cd ..

We now have 3 branches: default, which has v3 of all files, release-v1 which
has v1 of all files, and release-v2 with v2 of all files.

Narrow clone which should get all branches

  $ hg clone --narrow ssh://user@dummy/master narrow --include "f5"
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 12 changesets with 5 changes to 1 files (+2 heads)
  new changesets *:* (glob)
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd narrow
  $ hg log -G -T "{if(ellipsis, '...')}{node|short} ({branch}): {desc}\n"
  o  ...031f516143fe (release-v2): Hotfix 9 in v2
  |
  o  9cd7f7bb9ca1 (release-v2): Hotfix 5 in v2
  |
  o  ...37bbc88f3ef0 (release-v2): Hotfix 4 in v2
  |
  | @  ...dae2f368ca07 (default): Update 10 to v3
  | |
  | o  9c224e89cb31 (default): Update 5 to v3
  | |
  | o  ...04fb59c7c9dc (default): Update 4 to v3
  |/
  | o  b2253e82401f (release-v1): Hotfix 5 in v1
  | |
  | o  ...960ac37d74fd (release-v1): Hotfix 4 in v1
  | |
  o |  986298e3f347 (default): Update 5 to v2
  | |
  o |  ...75d539c667ec (default): Update 4 to v2
  |/
  o  04c71bd5707f (default): Add 5
  |
  o  ...881b3891d041 (default): Add 4
  

Narrow clone the first file, hitting edge condition where unaligned
changeset and manifest revnums cross branches.

  $ hg clone --narrow ssh://user@dummy/master narrow --include "f1"
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 10 changesets with 4 changes to 1 files (+2 heads)
  new changesets *:* (glob)
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd narrow
  $ hg log -G -T "{if(ellipsis, '...')}{node|short} ({branch}): {desc}\n"
  o  ...031f516143fe (release-v2): Hotfix 9 in v2
  |
  | @  ...dae2f368ca07 (default): Update 10 to v3
  | |
  | o  1f5d184b8e96 (default): Update 1 to v3
  |/
  | o  ...b2253e82401f (release-v1): Hotfix 5 in v1
  | |
  | o  133502f6b7e5 (release-v1): Hotfix 1 in v1
  | |
  o |  ...79165c83d644 (default): Update 10 to v2
  | |
  o |  c7b7a5f2f088 (default): Update 1 to v2
  | |
  | o  ...f0531a3db7a9 (release-v1): Start release for v1
  |/
  o  ...6a3f0f0abef3 (default): Add 10
  |
  o  e012ac15eaaa (default): Add 1