view tests/test-narrow-patterns.t @ 51681:522b4d729e89

mmap: populate the mapping by default

Without pre-population, accessing all data through a mmap can result in many
pagefault, reducing performance significantly. If the mmap is prepopulated, the
performance can no longer get slower than a full read.
(See benchmark number below)

In some cases were very few data is read, prepopulating can be overkill and
slower than populating on access (through page fault). So that behavior can be
controlled when the caller can pre-determine the best behavior.
(See benchmark number below)

In addition, testing with populating in a secondary thread yield great result
combining the best of each approach. This might be implemented in later
changesets.

In all cases, using mmap has a great effect on memory usage when many processes
run in parallel on the same machine.

### Benchmarks

# What did I run

A couple of month back I ran a large benchmark campaign to assess the impact of
various approach for using mmap with the revlog (and other files), it
highlighted a few benchmarks that capture the impact of the changes well. So to
validate this change I checked the following:

- log command displaying various revisions
  (read the changelog index)
- log command displaying the patch of listed revisions
  (read the changelog index, the manifest index and a few files indexes)
- unbundling a few revisions
  (read and write changelog, manifest and few files indexes, and walk the graph
  to update some cache)
- pushing a few revisions
  (read and write changelog, manifest and few files indexes, walk the graph to
  update some cache, performs various accesses locally and remotely during
  discovery)

Benchmarks were run using the default module policy (c+py) and the rust one. No
significant difference were found between the two implementation, so we will
present result using the default policy (unless otherwise specified).

I ran them on a few repositories :

- mercurial: a "public changeset only" copy of mercurial from 2018-08-01 using
  zstd compression and sparse-revlog

- pypy: a copy of pypy from 2018-08-01 using zstd compression and sparse-revlog

- netbeans: a copy of netbeans from 2018-08-01 using zstd compression and
  sparse-revlog

- mozilla-try: a copy of mozilla-try from 2019-02-18 using zstd compression and
  sparse-revlog

- mozilla-try persistent-nodemap: Same as the above but with a persistent
  nodemap. Used for the log --patch benchmark only

# Results

For the smaller repositories (mercurial, pypy), the impact of mmap is almost
imperceptible, other cost dominating the operation. The impact of prepopulating
is undiscernible in the benchmark we ran.

For larger repositories the benchmark support explanation given above:

On netbeans, the log can be about 1% faster without repopulation (for a
difference < 100ms) but unbundle becomes a bit slower, even when small.

### data-env-vars.name                             = netbeans-2018-08-01-zstd-sparse-revlog
  # benchmark.name                                 = hg.command.unbundle
  # benchmark.variants.issue6528                   = disabled
  # benchmark.variants.reuse-external-delta-parent = yes
  # benchmark.variants.revs                        = any-1-extra-rev
  # benchmark.variants.source                      = unbundle
  # benchmark.variants.verbosity                   = quiet
with-populate: 0.240157
no-populate:   0.265087  (+10.38%, +0.02)
  # benchmark.variants.revs                        = any-100-extra-rev
with-populate: 1.459518
no-populate:   1.481290   (+1.49%, +0.02)
 ## benchmark.name                                 = hg.command.push
  # benchmark.variants.explicit-rev                = none
  # benchmark.variants.issue6528                   = disabled
  # benchmark.variants.protocol                    = ssh
  # benchmark.variants.reuse-external-delta-parent = yes
  # benchmark.variants.revs                        = any-1-extra-rev
with-populate: 0.771919
no-populate:   0.792025   (+2.60%, +0.02)
  # benchmark.variants.revs                        = any-100-extra-rev
with-populate: 1.459518
no-populate:   1.481290   (+1.49%, +0.02)


For mozilla-try, the "slow down" from pre-populate for small `hg log` is more
visible, but still small in absolute time. (using rust value for the persistent
nodemap value to be relevant).

### data-env-vars.name            = mozilla-try-2019-02-18-ds2-pnm
  # benchmark.name                = hg.command.log
  # bin-env-vars.hg.flavor        = rust
  # benchmark.variants.patch      = yes
  # benchmark.variants.limit-rev  = 1
with-populate: 0.237813
no-populate:   0.229452   (-3.52%, -0.01)
  # benchmark.variants.limit-rev  = 10
  # benchmark.variants.patch      = yes
with-populate: 1.213578
no-populate:   1.205189
### data-env-vars.name            = mozilla-try-2019-02-18-zstd-sparse-revlog
  # benchmark.variants.limit-rev  = 1000
  # benchmark.variants.patch      = no
  # benchmark.variants.rev        = tip
with-populate: 0.198607
no-populate:   0.195038   (-1.80%, -0.00)

However pre-populating provide a significant boost on more complex operations
like unbundle or push:

### data-env-vars.name                             = mozilla-try-2019-02-18-zstd-sparse-revlog
  # benchmark.name                                 = hg.command.push
  # benchmark.variants.explicit-rev                = none
  # benchmark.variants.issue6528                   = disabled
  # benchmark.variants.protocol                    = ssh
  # benchmark.variants.reuse-external-delta-parent = yes
  # benchmark.variants.revs                        = any-1-extra-rev
with-populate: 4.798632
no-populate:   4.953295   (+3.22%, +0.15)
  # benchmark.variants.revs                        = any-100-extra-rev
with-populate: 4.903618
no-populate:   5.014963   (+2.27%, +0.11)
 ## benchmark.name                                 = hg.command.unbundle
  # benchmark.variants.revs                        = any-1-extra-rev
with-populate: 1.423411
no-populate:   1.585365  (+11.38%, +0.16)
  # benchmark.variants.revs                        = any-100-extra-rev
with-populate: 1.537909
no-populate:   1.688489   (+9.79%, +0.15)

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

initialize nested directories to validate complex include/exclude patterns

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

  $ echo root > root
  $ hg add root
  $ hg commit -m 'add root'

  $ for d in dir1 dir2 dir1/dirA dir1/dirB dir2/dirA dir2/dirB
  > do
  >   mkdir -p $d
  >   echo $d/foo > $d/foo
  >   hg add $d/foo
  >   hg commit -m "add $d/foo"
  >   echo $d/bar > $d/bar
  >   hg add $d/bar
  >   hg commit -m "add $d/bar"
  > done
#if execbit
  $ chmod +x dir1/dirA/foo
  $ hg commit -m "make dir1/dirA/foo executable"
#else
  $ hg import --bypass - <<EOF
  > # HG changeset patch
  > make dir1/dirA/foo executable
  > 
  > diff --git a/dir1/dirA/foo b/dir1/dirA/foo
  > old mode 100644
  > new mode 100755
  > EOF
  applying patch from stdin
  $ hg update -qr tip
#endif
  $ hg log -G -T '{rev} {node|short} {files}\n'
  @  13 c87ca422d521 dir1/dirA/foo
  |
  o  12 951b8a83924e dir2/dirB/bar
  |
  o  11 01ae5a51b563 dir2/dirB/foo
  |
  o  10 5eababdf0ac5 dir2/dirA/bar
  |
  o  9 99d690663739 dir2/dirA/foo
  |
  o  8 8e80155d5445 dir1/dirB/bar
  |
  o  7 406760310428 dir1/dirB/foo
  |
  o  6 623466a5f475 dir1/dirA/bar
  |
  o  5 06ff3a5be997 dir1/dirA/foo
  |
  o  4 33227af02764 dir2/bar
  |
  o  3 5e1f9d8d7c69 dir2/foo
  |
  o  2 594bc4b13d4a dir1/bar
  |
  o  1 47f480a08324 dir1/foo
  |
  o  0 2a4f0c3b67da root
  
  $ cd ..

clone a narrow portion of the master, such that we can widen it later

  $ hg clone --narrow ssh://user@dummy/master narrow \
  > --include dir1 \
  > --include dir2 \
  > --exclude dir1/dirA \
  > --exclude dir1/dirB \
  > --exclude dir2/dirA \
  > --exclude dir2/dirB
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 6 changesets with 4 changes to 4 files
  new changesets *:* (glob)
  updating to branch default
  4 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ cd narrow
  $ hg tracked
  I path:dir1
  I path:dir2
  X path:dir1/dirA
  X path:dir1/dirB
  X path:dir2/dirA
  X path:dir2/dirB
  $ hg manifest -r tip
  dir1/bar
  dir1/dirA/bar
  dir1/dirA/foo
  dir1/dirB/bar
  dir1/dirB/foo
  dir1/foo
  dir2/bar
  dir2/dirA/bar
  dir2/dirA/foo
  dir2/dirB/bar
  dir2/dirB/foo
  dir2/foo
  root
  $ find * | sort
  dir1
  dir1/bar
  dir1/foo
  dir2
  dir2/bar
  dir2/foo
  $ hg log -G -T '{rev} {node|short}{if(ellipsis, "...")} {files}\n'
  @  5 c87ca422d521... dir1/dirA/foo
  |
  o  4 33227af02764 dir2/bar
  |
  o  3 5e1f9d8d7c69 dir2/foo
  |
  o  2 594bc4b13d4a dir1/bar
  |
  o  1 47f480a08324 dir1/foo
  |
  o  0 2a4f0c3b67da... root
  

widen the narrow checkout

  $ hg tracked --removeexclude dir1/dirA
  comparing with ssh://user@dummy/master
  searching for changes
  saved backup bundle to $TESTTMP/narrow/.hg/strip-backup/*-widen.hg (glob)
  adding changesets
  adding manifests
  adding file changes
  added 9 changesets with 6 changes to 10 files
  $ hg tracked
  I path:dir1
  I path:dir2
  X path:dir1/dirB
  X path:dir2/dirA
  X path:dir2/dirB
  $ find * | sort
  dir1
  dir1/bar
  dir1/dirA
  dir1/dirA/bar
  dir1/dirA/foo
  dir1/foo
  dir2
  dir2/bar
  dir2/foo

#if execbit
  $ test -x dir1/dirA/foo && echo executable
  executable
  $ test -x dir1/dirA/bar || echo not executable
  not executable
#endif

  $ hg log -G -T '{rev} {node|short}{if(ellipsis, "...")} {files}\n'
  @  8 c87ca422d521 dir1/dirA/foo
  |
  o  7 951b8a83924e... dir2/dirB/bar
  |
  o  6 623466a5f475 dir1/dirA/bar
  |
  o  5 06ff3a5be997 dir1/dirA/foo
  |
  o  4 33227af02764 dir2/bar
  |
  o  3 5e1f9d8d7c69 dir2/foo
  |
  o  2 594bc4b13d4a dir1/bar
  |
  o  1 47f480a08324 dir1/foo
  |
  o  0 2a4f0c3b67da... root
  

widen narrow spec again, but exclude a file in previously included spec

  $ hg tracked --removeexclude dir2/dirB --addexclude dir1/dirA/bar
  comparing with ssh://user@dummy/master
  searching for changes
  looking for local changes to affected paths
  deleting data/dir1/dirA/bar.i (reporevlogstore !)
  deleting data/dir1/dirA/bar/0eca1d0cbdaea4651d1d04d71976a6d2d9bfaae5 (reposimplestore !)
  deleting data/dir1/dirA/bar/index (reposimplestore !)
  deleting unwanted files from working copy
  saved backup bundle to $TESTTMP/narrow/.hg/strip-backup/*-widen.hg (glob)
  adding changesets
  adding manifests
  adding file changes
  added 11 changesets with 7 changes to 12 files
  $ hg tracked
  I path:dir1
  I path:dir2
  X path:dir1/dirA/bar
  X path:dir1/dirB
  X path:dir2/dirA
  $ find * | sort
  dir1
  dir1/bar
  dir1/dirA
  dir1/dirA/foo
  dir1/foo
  dir2
  dir2/bar
  dir2/dirB
  dir2/dirB/bar
  dir2/dirB/foo
  dir2/foo
  $ hg log -G -T '{rev} {node|short}{if(ellipsis, "...")} {files}\n'
  @  10 c87ca422d521 dir1/dirA/foo
  |
  o  9 951b8a83924e dir2/dirB/bar
  |
  o  8 01ae5a51b563 dir2/dirB/foo
  |
  o  7 5eababdf0ac5... dir2/dirA/bar
  |
  o  6 623466a5f475... dir1/dirA/bar
  |
  o  5 06ff3a5be997 dir1/dirA/foo
  |
  o  4 33227af02764 dir2/bar
  |
  o  3 5e1f9d8d7c69 dir2/foo
  |
  o  2 594bc4b13d4a dir1/bar
  |
  o  1 47f480a08324 dir1/foo
  |
  o  0 2a4f0c3b67da... root
  

widen narrow spec yet again, excluding a directory in previous spec

  $ hg tracked --removeexclude dir2/dirA --addexclude dir1/dirA
  comparing with ssh://user@dummy/master
  searching for changes
  looking for local changes to affected paths
  deleting data/dir1/dirA/foo.i (reporevlogstore !)
  deleting data/dir1/dirA/foo/162caeb3d55dceb1fee793aa631ac8c73fcb8b5e (reposimplestore !)
  deleting data/dir1/dirA/foo/index (reposimplestore !)
  deleting unwanted files from working copy
  saved backup bundle to $TESTTMP/narrow/.hg/strip-backup/*-widen.hg (glob)
  adding changesets
  adding manifests
  adding file changes
  added 13 changesets with 8 changes to 14 files
  $ hg tracked
  I path:dir1
  I path:dir2
  X path:dir1/dirA
  X path:dir1/dirA/bar
  X path:dir1/dirB
  $ find * | sort
  dir1
  dir1/bar
  dir1/foo
  dir2
  dir2/bar
  dir2/dirA
  dir2/dirA/bar
  dir2/dirA/foo
  dir2/dirB
  dir2/dirB/bar
  dir2/dirB/foo
  dir2/foo
  $ hg log -G -T '{rev} {node|short}{if(ellipsis, "...")} {files}\n'
  @  12 c87ca422d521... dir1/dirA/foo
  |
  o  11 951b8a83924e dir2/dirB/bar
  |
  o  10 01ae5a51b563 dir2/dirB/foo
  |
  o  9 5eababdf0ac5 dir2/dirA/bar
  |
  o  8 99d690663739 dir2/dirA/foo
  |
  o  7 8e80155d5445... dir1/dirB/bar
  |
  o  6 623466a5f475... dir1/dirA/bar
  |
  o  5 06ff3a5be997... dir1/dirA/foo
  |
  o  4 33227af02764 dir2/bar
  |
  o  3 5e1f9d8d7c69 dir2/foo
  |
  o  2 594bc4b13d4a dir1/bar
  |
  o  1 47f480a08324 dir1/foo
  |
  o  0 2a4f0c3b67da... root
  

include a directory that was previously explicitly excluded

  $ hg tracked --removeexclude dir1/dirA
  comparing with ssh://user@dummy/master
  searching for changes
  saved backup bundle to $TESTTMP/narrow/.hg/strip-backup/*-widen.hg (glob)
  adding changesets
  adding manifests
  adding file changes
  added 13 changesets with 9 changes to 17 files
  $ hg tracked
  I path:dir1
  I path:dir2
  X path:dir1/dirA/bar
  X path:dir1/dirB
  $ find * | sort
  dir1
  dir1/bar
  dir1/dirA
  dir1/dirA/foo
  dir1/foo
  dir2
  dir2/bar
  dir2/dirA
  dir2/dirA/bar
  dir2/dirA/foo
  dir2/dirB
  dir2/dirB/bar
  dir2/dirB/foo
  dir2/foo
  $ hg log -G -T '{rev} {node|short}{if(ellipsis, "...")} {files}\n'
  @  12 c87ca422d521 dir1/dirA/foo
  |
  o  11 951b8a83924e dir2/dirB/bar
  |
  o  10 01ae5a51b563 dir2/dirB/foo
  |
  o  9 5eababdf0ac5 dir2/dirA/bar
  |
  o  8 99d690663739 dir2/dirA/foo
  |
  o  7 8e80155d5445... dir1/dirB/bar
  |
  o  6 623466a5f475... dir1/dirA/bar
  |
  o  5 06ff3a5be997 dir1/dirA/foo
  |
  o  4 33227af02764 dir2/bar
  |
  o  3 5e1f9d8d7c69 dir2/foo
  |
  o  2 594bc4b13d4a dir1/bar
  |
  o  1 47f480a08324 dir1/foo
  |
  o  0 2a4f0c3b67da... root
  

  $ cd ..

clone a narrow portion of the master, such that we can widen it later

  $ hg clone --narrow ssh://user@dummy/master narrow2 --include dir1/dirA
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 5 changesets with 2 changes to 2 files
  new changesets *:* (glob)
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd narrow2
  $ find * | sort
  dir1
  dir1/dirA
  dir1/dirA/bar
  dir1/dirA/foo
  $ hg tracked --addinclude dir1
  comparing with ssh://user@dummy/master
  searching for changes
  saved backup bundle to $TESTTMP/narrow2/.hg/strip-backup/*-widen.hg (glob)
  adding changesets
  adding manifests
  adding file changes
  added 10 changesets with 6 changes to 8 files
  $ find * | sort
  dir1
  dir1/bar
  dir1/dirA
  dir1/dirA/bar
  dir1/dirA/foo
  dir1/dirB
  dir1/dirB/bar
  dir1/dirB/foo
  dir1/foo
  $ hg log -G -T '{rev} {node|short}{if(ellipsis, "...")} {files}\n'
  @  9 c87ca422d521 dir1/dirA/foo
  |
  o  8 951b8a83924e... dir2/dirB/bar
  |
  o  7 8e80155d5445 dir1/dirB/bar
  |
  o  6 406760310428 dir1/dirB/foo
  |
  o  5 623466a5f475 dir1/dirA/bar
  |
  o  4 06ff3a5be997 dir1/dirA/foo
  |
  o  3 33227af02764... dir2/bar
  |
  o  2 594bc4b13d4a dir1/bar
  |
  o  1 47f480a08324 dir1/foo
  |
  o  0 2a4f0c3b67da... root
  

Illegal patterns are rejected

  $ hg tracked --addinclude glob:**
  abort: invalid prefix on narrow pattern: glob:**
  (narrow patterns must begin with one of the following: path:, rootfilesin:)
  [255]

  $ hg tracked --addexclude set:ignored
  abort: invalid prefix on narrow pattern: set:ignored
  (narrow patterns must begin with one of the following: path:, rootfilesin:)
  [255]

  $ cat .hg/store/narrowspec
  [include]
  path:dir1
  path:dir1/dirA
  [exclude]

  $ cat > .hg/store/narrowspec << EOF
  > [include]
  > glob:**
  > EOF

  $ hg tracked
  abort: invalid prefix on narrow pattern: glob:**
  (narrow patterns must begin with one of the following: path:, rootfilesin:)
  [255]

  $ cat > .hg/store/narrowspec << EOF
  > [include]
  > path:.
  > [exclude]
  > set:ignored
  > EOF

  $ hg tracked
  abort: invalid prefix on narrow pattern: set:ignored
  (narrow patterns must begin with one of the following: path:, rootfilesin:)
  [255]