view tests/test-patchbomb-bookmark.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

Create @ bookmark as main reference

  $ hg init repo
  $ cd repo
  $ echo "[extensions]" >> $HGRCPATH
  $ echo "patchbomb=" >> $HGRCPATH
  $ hg book @

Create a dummy revision that must never be exported

  $ echo no > no
  $ hg ci -Amno -d '6 0'
  adding no

Create a feature and use -B

  $ hg book booktest
  $ echo first > a
  $ hg ci -Amfirst -d '7 0'
  adding a
  $ echo second > b
  $ hg ci -Amsecond -d '8 0'
  adding b
  $ hg email --date '1981-1-1 0:1' -n -t foo -s bookmark -B booktest
  From [test]: test
  this patch series consists of 2 patches.
  
  
  Write the introductory message for the patch series.
  
  Cc: 
  
  displaying [PATCH 0 of 2] bookmark ...
  MIME-Version: 1.0
  Content-Type: text/plain; charset="us-ascii"
  Content-Transfer-Encoding: 7bit
  Subject: [PATCH 0 of 2] bookmark
  Message-Id: <patchbomb.347155260@test-hostname>
  User-Agent: Mercurial-patchbomb/* (glob)
  Date: Thu, 01 Jan 1981 00:01:00 +0000
  From: test
  To: foo
  
  
  displaying [PATCH 1 of 2] first ...
  MIME-Version: 1.0
  Content-Type: text/plain; charset="us-ascii"
  Content-Transfer-Encoding: 7bit
  Subject: [PATCH 1 of 2] first
  X-Mercurial-Node: accde9b8b6dce861c185d0825c1affc09a79cb26
  X-Mercurial-Series-Index: 1
  X-Mercurial-Series-Total: 2
  Message-Id: <accde9b8b6dce861c185.347155261@test-hostname>
  X-Mercurial-Series-Id: <accde9b8b6dce861c185.347155261@test-hostname>
  In-Reply-To: <patchbomb.347155260@test-hostname>
  References: <patchbomb.347155260@test-hostname>
  User-Agent: Mercurial-patchbomb/* (glob)
  Date: Thu, 01 Jan 1981 00:01:01 +0000
  From: test
  To: foo
  
  # HG changeset patch
  # User test
  # Date 7 0
  #      Thu Jan 01 00:00:07 1970 +0000
  # Node ID accde9b8b6dce861c185d0825c1affc09a79cb26
  # Parent  043bd3889e5aaf7d88fe3713cf425f782ad2fb71
  first
  
  diff -r 043bd3889e5a -r accde9b8b6dc a
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/a	Thu Jan 01 00:00:07 1970 +0000
  @@ -0,0 +1,1 @@
  +first
  
  displaying [PATCH 2 of 2] second ...
  MIME-Version: 1.0
  Content-Type: text/plain; charset="us-ascii"
  Content-Transfer-Encoding: 7bit
  Subject: [PATCH 2 of 2] second
  X-Mercurial-Node: 417defd1559c396ba06a44dce8dc1c2d2d653f3f
  X-Mercurial-Series-Index: 2
  X-Mercurial-Series-Total: 2
  Message-Id: <417defd1559c396ba06a.347155262@test-hostname>
  X-Mercurial-Series-Id: <accde9b8b6dce861c185.347155261@test-hostname>
  In-Reply-To: <patchbomb.347155260@test-hostname>
  References: <patchbomb.347155260@test-hostname>
  User-Agent: Mercurial-patchbomb/* (glob)
  Date: Thu, 01 Jan 1981 00:01:02 +0000
  From: test
  To: foo
  
  # HG changeset patch
  # User test
  # Date 8 0
  #      Thu Jan 01 00:00:08 1970 +0000
  # Node ID 417defd1559c396ba06a44dce8dc1c2d2d653f3f
  # Parent  accde9b8b6dce861c185d0825c1affc09a79cb26
  second
  
  diff -r accde9b8b6dc -r 417defd1559c b
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/b	Thu Jan 01 00:00:08 1970 +0000
  @@ -0,0 +1,1 @@
  +second
  
Do the same and combine with -o only one must be exported

  $ cd ..
  $ hg clone repo repo2
  updating to bookmark @
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd repo
  $ hg up @
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  (activating bookmark @)
  $ hg book outgoing
  $ echo 1 > x
  $ hg ci -Am1 -d '8 0'
  adding x
  created new head
  $ hg push ../repo2 -B outgoing
  pushing to ../repo2
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)
  exporting bookmark outgoing
  $ echo 2 > y
  $ hg ci -Am2 -d '9 0'
  adding y
  $ hg email --date '1982-1-1 0:1' -n -t foo -s bookmark -B outgoing -o ../repo2
  comparing with ../repo2
  From [test]: test
  this patch series consists of 1 patches.
  
  Cc: 
  
  displaying [PATCH] bookmark ...
  MIME-Version: 1.0
  Content-Type: text/plain; charset="us-ascii"
  Content-Transfer-Encoding: 7bit
  Subject: [PATCH] bookmark
  X-Mercurial-Node: 8dab2639fd35f1e337ad866c372a5c44f1064e3c
  X-Mercurial-Series-Index: 1
  X-Mercurial-Series-Total: 1
  Message-Id: <8dab2639fd35f1e337ad.378691260@test-hostname>
  X-Mercurial-Series-Id: <8dab2639fd35f1e337ad.378691260@test-hostname>
  User-Agent: Mercurial-patchbomb/* (glob)
  Date: Fri, 01 Jan 1982 00:01:00 +0000
  From: test
  To: foo
  
  # HG changeset patch
  # User test
  # Date 9 0
  #      Thu Jan 01 00:00:09 1970 +0000
  # Node ID 8dab2639fd35f1e337ad866c372a5c44f1064e3c
  # Parent  0b24b8316483bf30bfc3e4d4168e922b169dbe66
  2
  
  diff -r 0b24b8316483 -r 8dab2639fd35 y
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/y	Thu Jan 01 00:00:09 1970 +0000
  @@ -0,0 +1,1 @@
  +2