view tests/test-remotefilelog-local.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

#require no-windows

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

  $ hg init master
  $ cd master
  $ cat >> .hg/hgrc <<EOF
  > [remotefilelog]
  > server=True
  > EOF
  $ echo x > x
  $ echo y > y
  $ echo z > z
  $ hg commit -qAm xy

  $ cd ..

  $ hgcloneshallow ssh://user@dummy/master shallow -q
  3 files fetched over 1 fetches - (3 misses, 0.00% hit ratio) over *s (glob)
  $ cd shallow

# status

  $ clearcache
  $ echo xx > x
  $ echo yy > y
  $ touch a
  $ hg status
  M x
  M y
  ? a
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
  $ hg add a
  $ hg status
  M x
  M y
  A a

# diff

  $ hg debugrebuilddirstate # fixes dirstate non-determinism
  $ hg add a
  $ clearcache
  $ hg diff
  diff -r f3d0bb0d1e48 x
  --- a/x* (glob)
  +++ b/x* (glob)
  @@ -1,1 +1,1 @@
  -x
  +xx
  diff -r f3d0bb0d1e48 y
  --- a/y* (glob)
  +++ b/y* (glob)
  @@ -1,1 +1,1 @@
  -y
  +yy
  3 files fetched over 1 fetches - (3 misses, 0.00% hit ratio) over *s (glob)

# local commit

  $ clearcache
  $ echo a > a
  $ echo xxx > x
  $ echo yyy > y
  $ hg commit -m a
  ? files fetched over 1 fetches - (? misses, 0.00% hit ratio) over *s (glob)

# local commit where the dirstate is clean -- ensure that we do just one fetch
# (update to a commit on the server first)

  $ hg --config debug.dirstate.delaywrite=1 up 0
  2 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ clearcache
  $ hg debugdirstate
  n 644          2 * x (glob)
  n 644          2 * y (glob)
  n 644          2 * z (glob)
  $ echo xxxx > x
  $ echo yyyy > y
  $ hg commit -m x
  created new head
  2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob)

# restore state for future tests

  $ hg -q strip .
  $ hg -q up tip

# rebase

  $ clearcache
  $ cd ../master
  $ echo w > w
  $ hg commit -qAm w

  $ cd ../shallow
  $ hg pull
  pulling from ssh://user@dummy/master
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 0 changes to 0 files (+1 heads)
  new changesets fed61014d323
  (run 'hg heads' to see heads, 'hg merge' to merge)

  $ hg rebase -d tip
  rebasing 1:9abfe7bca547 "a"
  saved backup bundle to $TESTTMP/shallow/.hg/strip-backup/9abfe7bca547-8b11e5ff-rebase.hg (glob)
  3 files fetched over 2 fetches - (3 misses, 0.00% hit ratio) over *s (glob)

# strip

  $ clearcache
  $ hg debugrebuilddirstate # fixes dirstate non-determinism
  $ hg strip -r .
  2 files updated, 0 files merged, 1 files removed, 0 files unresolved
  saved backup bundle to $TESTTMP/shallow/.hg/strip-backup/19edf50f4de7-df3d0f74-backup.hg (glob)
  4 files fetched over 2 fetches - (4 misses, 0.00% hit ratio) over *s (glob)

# unbundle

  $ clearcache
  $ ls
  w
  x
  y
  z

  $ hg debugrebuilddirstate # fixes dirstate non-determinism
  $ hg unbundle .hg/strip-backup/19edf50f4de7-df3d0f74-backup.hg
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 0 changes to 0 files
  new changesets 19edf50f4de7 (1 drafts)
  (run 'hg update' to get a working copy)

  $ hg up
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  4 files fetched over 1 fetches - (4 misses, 0.00% hit ratio) over *s (glob)
  $ cat a
  a

# revert

  $ clearcache
  $ hg revert -r .~2 y z
  no changes needed to z
  2 files fetched over 2 fetches - (2 misses, 0.00% hit ratio) over *s (glob)
  $ hg checkout -C -r . -q

# explicit bundle should produce full bundle file

  $ hg bundle -r 2 --base 1 ../local.bundle
  1 changesets found
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
  $ cd ..

  $ hgcloneshallow ssh://user@dummy/master shallow2 -q
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
  $ cd shallow2
  $ hg unbundle ../local.bundle
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 3 changes to 3 files
  new changesets 19edf50f4de7 (1 drafts)
  (run 'hg update' to get a working copy)

  $ hg log -r 2 --stat
  changeset:   2:19edf50f4de7
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     a
  
   a |  1 +
   x |  2 +-
   y |  2 +-
   3 files changed, 3 insertions(+), 2 deletions(-)
  
# Merge

  $ echo merge >> w
  $ hg commit -m w
  created new head
  $ hg merge 2
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg commit -m merge
  $ hg strip -q -r ".^"

# commit without producing new node

  $ cd $TESTTMP
  $ hgcloneshallow ssh://user@dummy/master shallow3 -q
  $ cd shallow3
  $ echo 1 > A
  $ hg commit -m foo -A A
  $ hg log -r . -T '{node}\n'
  383ce605500277f879b7460a16ba620eb6930b7f
  $ hg update -r '.^' -q
  $ echo 1 > A
  $ hg commit -m foo -A A
  $ hg log -r . -T '{node}\n'
  383ce605500277f879b7460a16ba620eb6930b7f