view tests/test-journal-share.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

Journal extension test: tests the share extension support

  $ cat >> testmocks.py << EOF
  > # mock out procutil.getuser() and util.makedate() to supply testable values
  > import os
  > from mercurial import util
  > from mercurial.utils import procutil
  > def mockgetuser():
  >     return b'foobar'
  > 
  > def mockmakedate():
  >     filename = os.path.join(os.environ['TESTTMP'], 'testtime')
  >     try:
  >         with open(filename, 'rb') as timef:
  >             time = float(timef.read()) + 1
  >     except IOError:
  >         time = 0.0
  >     with open(filename, 'wb') as timef:
  >         timef.write(str(time))
  >     return (time, 0)
  > 
  > procutil.getuser = mockgetuser
  > util.makedate = mockmakedate
  > EOF

  $ cat >> $HGRCPATH << EOF
  > [extensions]
  > journal=
  > share=
  > testmocks=`pwd`/testmocks.py
  > [remotenames]
  > rename.default=remote
  > EOF

  $ hg init repo
  $ cd repo
  $ hg bookmark bm
  $ touch file0
  $ hg commit -Am file0-added
  adding file0
  $ hg journal --all
  previous locations of the working copy and bookmarks:
  0fd3805711f9  .         commit -Am file0-added
  0fd3805711f9  bm        commit -Am file0-added

A shared working copy initially receives the same bookmarks and working copy

  $ cd ..
  $ hg share repo shared1
  updating working directory
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd shared1
  $ hg journal --all
  previous locations of the working copy and bookmarks:
  0fd3805711f9  .         share repo shared1

unless you explicitly share bookmarks

  $ cd ..
  $ hg share --bookmarks repo shared2
  updating working directory
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd shared2
  $ hg journal --all
  previous locations of the working copy and bookmarks:
  0fd3805711f9  .         share --bookmarks repo shared2
  0fd3805711f9  bm        commit -Am file0-added

Moving the bookmark in the original repository is only shown in the repository
that shares bookmarks

  $ cd ../repo
  $ touch file1
  $ hg commit -Am file1-added
  adding file1
  $ cd ../shared1
  $ hg journal --all
  previous locations of the working copy and bookmarks:
  0fd3805711f9  .         share repo shared1
  $ cd ../shared2
  $ hg journal --all
  previous locations of the working copy and bookmarks:
  4f354088b094  bm        commit -Am file1-added
  0fd3805711f9  .         share --bookmarks repo shared2
  0fd3805711f9  bm        commit -Am file0-added

But working copy changes are always 'local'

  $ cd ../repo
  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  (leaving bookmark bm)
  $ hg journal --all
  previous locations of the working copy and bookmarks:
  0fd3805711f9  .         up 0
  4f354088b094  .         commit -Am file1-added
  4f354088b094  bm        commit -Am file1-added
  0fd3805711f9  .         commit -Am file0-added
  0fd3805711f9  bm        commit -Am file0-added
  $ cd ../shared2
  $ hg journal --all
  previous locations of the working copy and bookmarks:
  4f354088b094  bm        commit -Am file1-added
  0fd3805711f9  .         share --bookmarks repo shared2
  0fd3805711f9  bm        commit -Am file0-added
  $ hg up tip
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg journal
  previous locations of '.':
  0fd3805711f9  up 0
  4f354088b094  up tip
  0fd3805711f9  share --bookmarks repo shared2

Unsharing works as expected; the journal remains consistent

  $ cd ../shared1
  $ hg unshare
  $ hg journal --all
  previous locations of the working copy and bookmarks:
  0fd3805711f9  .         share repo shared1
  $ cd ../shared2
  $ hg unshare
  $ hg journal --all
  previous locations of the working copy and bookmarks:
  0fd3805711f9  .         up 0
  4f354088b094  .         up tip
  4f354088b094  bm        commit -Am file1-added
  0fd3805711f9  .         share --bookmarks repo shared2
  0fd3805711f9  bm        commit -Am file0-added

New journal entries in the source repo no longer show up in the other working copies

  $ cd ../repo
  $ hg bookmark newbm -r tip
  $ hg journal newbm
  previous locations of 'newbm':
  4f354088b094  bookmark newbm -r tip
  $ cd ../shared2
  $ hg journal newbm
  previous locations of 'newbm':
  no recorded locations

This applies for both directions

  $ hg bookmark shared2bm -r tip
  $ hg journal shared2bm
  previous locations of 'shared2bm':
  4f354088b094  bookmark shared2bm -r tip
  $ cd ../repo
  $ hg journal shared2bm
  previous locations of 'shared2bm':
  no recorded locations