annotate tests/test-bundle2-multiple-changegroups.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)

Create an extension to test bundle2 with multiple changegroups

  $ cat > bundle2.py <<EOF
  > """
  > """
  > from mercurial import changegroup, discovery, exchange
  > 
  > def _getbundlechangegrouppart(bundler, repo, source, bundlecaps=None,
  >                               b2caps=None, heads=None, common=None,
  >                               **kwargs):
  >     # Create two changegroups given the common changesets and heads for the
  >     # changegroup part we are being requested. Use the parent of each head
  >     # in 'heads' as intermediate heads for the first changegroup.
  >     intermediates = [repo[r].p1().node() for r in heads]
  >     outgoing = discovery.outgoing(repo, common, intermediates)
  >     cg = changegroup.makechangegroup(repo, outgoing, b'01',
  >                                      source, bundlecaps=bundlecaps)
  >     bundler.newpart(b'output', data=b'changegroup1')
  >     bundler.newpart(b'changegroup', data=cg.getchunks())
  >     outgoing = discovery.outgoing(repo, common + intermediates, heads)
  >     cg = changegroup.makechangegroup(repo, outgoing, b'01',
  >                                      source, bundlecaps=bundlecaps)
  >     bundler.newpart(b'output', data=b'changegroup2')
  >     bundler.newpart(b'changegroup', data=cg.getchunks())
  > 
  > def _pull(repo, *args, **kwargs):
  >   pullop = _orig_pull(repo, *args, **kwargs)
  >   repo.ui.write(b'pullop.cgresult is %d\n' % pullop.cgresult)
  >   return pullop
  > 
  > _orig_pull = exchange.pull
  > exchange.pull = _pull
  > exchange.getbundle2partsmapping[b'changegroup'] = _getbundlechangegrouppart
  > EOF

  $ cat >> $HGRCPATH << EOF
  > [command-templates]
  > log={rev}:{node|short} {phase} {author} {bookmarks} {desc|firstline}
  > EOF

Start with a simple repository with a single commit

  $ hg init repo
  $ cd repo
  $ cat > .hg/hgrc << EOF
  > [extensions]
  > bundle2=$TESTTMP/bundle2.py
  > EOF

  $ echo A > A
  $ hg commit -A -m A -q
  $ cd ..

Clone

  $ hg clone -q repo clone

Add two linear commits

  $ cd repo
  $ echo B > B
  $ hg commit -A -m B -q
  $ echo C > C
  $ hg commit -A -m C -q

  $ cd ../clone
  $ cat >> .hg/hgrc <<EOF
  > [hooks]
  > pretxnchangegroup = sh -c "printenv.py --line pretxnchangegroup"
  > changegroup = sh -c "printenv.py --line changegroup"
  > incoming = sh -c "printenv.py --line incoming"
  > EOF

Pull the new commits in the clone

  $ hg pull
  pulling from $TESTTMP/repo
  searching for changes
  remote: changegroup1
  adding changesets
  adding manifests
  adding file changes
  pretxnchangegroup hook: HG_HOOKNAME=pretxnchangegroup
  HG_HOOKTYPE=pretxnchangegroup
  HG_NODE=27547f69f25460a52fff66ad004e58da7ad3fb56
  HG_NODE_LAST=27547f69f25460a52fff66ad004e58da7ad3fb56
  HG_PENDING=$TESTTMP/clone
  HG_SOURCE=pull
  HG_TXNID=TXN:$ID$
  HG_TXNNAME=pull
  file:/*/$TESTTMP/repo (glob)
  HG_URL=file:$TESTTMP/repo
  
  remote: changegroup2
  adding changesets
  adding manifests
  adding file changes
  pretxnchangegroup hook: HG_HOOKNAME=pretxnchangegroup
  HG_HOOKTYPE=pretxnchangegroup
  HG_NODE=f838bfaca5c7226600ebcfd84f3c3c13a28d3757
  HG_NODE_LAST=f838bfaca5c7226600ebcfd84f3c3c13a28d3757
  HG_PENDING=$TESTTMP/clone
  HG_PHASES_MOVED=1
  HG_SOURCE=pull
  HG_TXNID=TXN:$ID$
  HG_TXNNAME=pull
  file:/*/$TESTTMP/repo (glob)
  HG_URL=file:$TESTTMP/repo
  
  added 2 changesets with 2 changes to 2 files
  new changesets 27547f69f254:f838bfaca5c7
  changegroup hook: HG_HOOKNAME=changegroup
  HG_HOOKTYPE=changegroup
  HG_NODE=27547f69f25460a52fff66ad004e58da7ad3fb56
  HG_NODE_LAST=27547f69f25460a52fff66ad004e58da7ad3fb56
  HG_SOURCE=pull
  HG_TXNID=TXN:$ID$
  HG_TXNNAME=pull
  file:/*/$TESTTMP/repo (glob)
  HG_URL=file:$TESTTMP/repo
  
  incoming hook: HG_HOOKNAME=incoming
  HG_HOOKTYPE=incoming
  HG_NODE=27547f69f25460a52fff66ad004e58da7ad3fb56
  HG_SOURCE=pull
  HG_TXNID=TXN:$ID$
  HG_TXNNAME=pull
  file:/*/$TESTTMP/repo (glob)
  HG_URL=file:$TESTTMP/repo
  
  changegroup hook: HG_HOOKNAME=changegroup
  HG_HOOKTYPE=changegroup
  HG_NODE=f838bfaca5c7226600ebcfd84f3c3c13a28d3757
  HG_NODE_LAST=f838bfaca5c7226600ebcfd84f3c3c13a28d3757
  HG_PHASES_MOVED=1
  HG_SOURCE=pull
  HG_TXNID=TXN:$ID$
  HG_TXNNAME=pull
  file:/*/$TESTTMP/repo (glob)
  HG_URL=file:$TESTTMP/repo
  
  incoming hook: HG_HOOKNAME=incoming
  HG_HOOKTYPE=incoming
  HG_NODE=f838bfaca5c7226600ebcfd84f3c3c13a28d3757
  HG_PHASES_MOVED=1
  HG_SOURCE=pull
  HG_TXNID=TXN:$ID$
  HG_TXNNAME=pull
  file:/*/$TESTTMP/repo (glob)
  HG_URL=file:$TESTTMP/repo
  
  pullop.cgresult is 1
  (run 'hg update' to get a working copy)
  $ hg update
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg log -G
  @  2:f838bfaca5c7 public test  C
  |
  o  1:27547f69f254 public test  B
  |
  o  0:4a2df7238c3b public test  A
  
Add more changesets with multiple heads to the original repository

  $ cd ../repo
  $ echo D > D
  $ hg commit -A -m D -q
  $ hg up -r 1
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ echo E > E
  $ hg commit -A -m E -q
  $ echo F > F
  $ hg commit -A -m F -q
  $ hg up -r 1
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ echo G > G
  $ hg commit -A -m G -q
  $ hg up -r 3
  2 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo H > H
  $ hg commit -A -m H -q
  $ hg log -G
  @  7:5cd59d311f65 draft test  H
  |
  | o  6:1d14c3ce6ac0 draft test  G
  | |
  | | o  5:7f219660301f draft test  F
  | | |
  | | o  4:8a5212ebc852 draft test  E
  | |/
  o |  3:b3325c91a4d9 draft test  D
  | |
  o |  2:f838bfaca5c7 draft test  C
  |/
  o  1:27547f69f254 draft test  B
  |
  o  0:4a2df7238c3b draft test  A
  
New heads are reported during transfer and properly accounted for in
pullop.cgresult

  $ cd ../clone
  $ hg pull
  pulling from $TESTTMP/repo
  searching for changes
  remote: changegroup1
  adding changesets
  adding manifests
  adding file changes
  pretxnchangegroup hook: HG_HOOKNAME=pretxnchangegroup
  HG_HOOKTYPE=pretxnchangegroup
  HG_NODE=b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e
  HG_NODE_LAST=8a5212ebc8527f9fb821601504794e3eb11a1ed3
  HG_PENDING=$TESTTMP/clone
  HG_SOURCE=pull
  HG_TXNID=TXN:$ID$
  HG_TXNNAME=pull
  file:/*/$TESTTMP/repo (glob)
  HG_URL=file:$TESTTMP/repo
  
  remote: changegroup2
  adding changesets
  adding manifests
  adding file changes
  pretxnchangegroup hook: HG_HOOKNAME=pretxnchangegroup
  HG_HOOKTYPE=pretxnchangegroup
  HG_NODE=7f219660301fe4c8a116f714df5e769695cc2b46
  HG_NODE_LAST=5cd59d311f6508b8e0ed28a266756c859419c9f1
  HG_PENDING=$TESTTMP/clone
  HG_PHASES_MOVED=1
  HG_SOURCE=pull
  HG_TXNID=TXN:$ID$
  HG_TXNNAME=pull
  file:/*/$TESTTMP/repo (glob)
  HG_URL=file:$TESTTMP/repo
  
  added 5 changesets with 5 changes to 5 files (+2 heads)
  new changesets b3325c91a4d9:5cd59d311f65
  changegroup hook: HG_HOOKNAME=changegroup
  HG_HOOKTYPE=changegroup
  HG_NODE=b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e
  HG_NODE_LAST=8a5212ebc8527f9fb821601504794e3eb11a1ed3
  HG_SOURCE=pull
  HG_TXNID=TXN:$ID$
  HG_TXNNAME=pull
  file:/*/$TESTTMP/repo (glob)
  HG_URL=file:$TESTTMP/repo
  
  incoming hook: HG_HOOKNAME=incoming
  HG_HOOKTYPE=incoming
  HG_NODE=b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e
  HG_SOURCE=pull
  HG_TXNID=TXN:$ID$
  HG_TXNNAME=pull
  file:/*/$TESTTMP/repo (glob)
  HG_URL=file:$TESTTMP/repo
  
  incoming hook: HG_HOOKNAME=incoming
  HG_HOOKTYPE=incoming
  HG_NODE=8a5212ebc8527f9fb821601504794e3eb11a1ed3
  HG_SOURCE=pull
  HG_TXNID=TXN:$ID$
  HG_TXNNAME=pull
  file:/*/$TESTTMP/repo (glob)
  HG_URL=file:$TESTTMP/repo
  
  changegroup hook: HG_HOOKNAME=changegroup
  HG_HOOKTYPE=changegroup
  HG_NODE=7f219660301fe4c8a116f714df5e769695cc2b46
  HG_NODE_LAST=5cd59d311f6508b8e0ed28a266756c859419c9f1
  HG_PHASES_MOVED=1
  HG_SOURCE=pull
  HG_TXNID=TXN:$ID$
  HG_TXNNAME=pull
  file:/*/$TESTTMP/repo (glob)
  HG_URL=file:$TESTTMP/repo
  
  incoming hook: HG_HOOKNAME=incoming
  HG_HOOKTYPE=incoming
  HG_NODE=7f219660301fe4c8a116f714df5e769695cc2b46
  HG_PHASES_MOVED=1
  HG_SOURCE=pull
  HG_TXNID=TXN:$ID$
  HG_TXNNAME=pull
  file:/*/$TESTTMP/repo (glob)
  HG_URL=file:$TESTTMP/repo
  
  incoming hook: HG_HOOKNAME=incoming
  HG_HOOKTYPE=incoming
  HG_NODE=1d14c3ce6ac0582d2809220d33e8cd7a696e0156
  HG_PHASES_MOVED=1
  HG_SOURCE=pull
  HG_TXNID=TXN:$ID$
  HG_TXNNAME=pull
  file:/*/$TESTTMP/repo (glob)
  HG_URL=file:$TESTTMP/repo
  
  incoming hook: HG_HOOKNAME=incoming
  HG_HOOKTYPE=incoming
  HG_NODE=5cd59d311f6508b8e0ed28a266756c859419c9f1
  HG_PHASES_MOVED=1
  HG_SOURCE=pull
  HG_TXNID=TXN:$ID$
  HG_TXNNAME=pull
  file:/*/$TESTTMP/repo (glob)
  HG_URL=file:$TESTTMP/repo
  
  pullop.cgresult is 3
  (run 'hg heads' to see heads, 'hg merge' to merge)
  $ hg log -G
  o  7:5cd59d311f65 public test  H
  |
  | o  6:1d14c3ce6ac0 public test  G
  | |
  | | o  5:7f219660301f public test  F
  | | |
  | | o  4:8a5212ebc852 public test  E
  | |/
  o |  3:b3325c91a4d9 public test  D
  | |
  @ |  2:f838bfaca5c7 public test  C
  |/
  o  1:27547f69f254 public test  B
  |
  o  0:4a2df7238c3b public test  A
  
Removing a head from the original repository by merging it

  $ cd ../repo
  $ hg merge -r 6 -q
  $ hg commit -m Merge
  $ echo I > I
  $ hg commit -A -m H -q
  $ hg log -G
  @  9:9d18e5bd9ab0 draft test  H
  |
  o    8:71bd7b46de72 draft test  Merge
  |\
  | o  7:5cd59d311f65 draft test  H
  | |
  o |  6:1d14c3ce6ac0 draft test  G
  | |
  | | o  5:7f219660301f draft test  F
  | | |
  +---o  4:8a5212ebc852 draft test  E
  | |
  | o  3:b3325c91a4d9 draft test  D
  | |
  | o  2:f838bfaca5c7 draft test  C
  |/
  o  1:27547f69f254 draft test  B
  |
  o  0:4a2df7238c3b draft test  A
  
Removed heads are reported during transfer and properly accounted for in
pullop.cgresult

  $ cd ../clone
  $ hg pull
  pulling from $TESTTMP/repo
  searching for changes
  remote: changegroup1
  adding changesets
  adding manifests
  adding file changes
  pretxnchangegroup hook: HG_HOOKNAME=pretxnchangegroup
  HG_HOOKTYPE=pretxnchangegroup
  HG_NODE=71bd7b46de72e69a32455bf88d04757d542e6cf4
  HG_NODE_LAST=71bd7b46de72e69a32455bf88d04757d542e6cf4
  HG_PENDING=$TESTTMP/clone
  HG_SOURCE=pull
  HG_TXNID=TXN:$ID$
  HG_TXNNAME=pull
  file:/*/$TESTTMP/repo (glob)
  HG_URL=file:$TESTTMP/repo
  
  remote: changegroup2
  adding changesets
  adding manifests
  adding file changes
  pretxnchangegroup hook: HG_HOOKNAME=pretxnchangegroup
  HG_HOOKTYPE=pretxnchangegroup
  HG_NODE=9d18e5bd9ab09337802595d49f1dad0c98df4d84
  HG_NODE_LAST=9d18e5bd9ab09337802595d49f1dad0c98df4d84
  HG_PENDING=$TESTTMP/clone
  HG_PHASES_MOVED=1
  HG_SOURCE=pull
  HG_TXNID=TXN:$ID$
  HG_TXNNAME=pull
  file:/*/$TESTTMP/repo (glob)
  HG_URL=file:$TESTTMP/repo
  
  added 2 changesets with 1 changes to 1 files (-1 heads)
  new changesets 71bd7b46de72:9d18e5bd9ab0
  changegroup hook: HG_HOOKNAME=changegroup
  HG_HOOKTYPE=changegroup
  HG_NODE=71bd7b46de72e69a32455bf88d04757d542e6cf4
  HG_NODE_LAST=71bd7b46de72e69a32455bf88d04757d542e6cf4
  HG_SOURCE=pull
  HG_TXNID=TXN:$ID$
  HG_TXNNAME=pull
  file:/*/$TESTTMP/repo (glob)
  HG_URL=file:$TESTTMP/repo
  
  incoming hook: HG_HOOKNAME=incoming
  HG_HOOKTYPE=incoming
  HG_NODE=71bd7b46de72e69a32455bf88d04757d542e6cf4
  HG_SOURCE=pull
  HG_TXNID=TXN:$ID$
  HG_TXNNAME=pull
  file:/*/$TESTTMP/repo (glob)
  HG_URL=file:$TESTTMP/repo
  
  changegroup hook: HG_HOOKNAME=changegroup
  HG_HOOKTYPE=changegroup
  HG_NODE=9d18e5bd9ab09337802595d49f1dad0c98df4d84
  HG_NODE_LAST=9d18e5bd9ab09337802595d49f1dad0c98df4d84
  HG_PHASES_MOVED=1
  HG_SOURCE=pull
  HG_TXNID=TXN:$ID$
  HG_TXNNAME=pull
  file:/*/$TESTTMP/repo (glob)
  HG_URL=file:$TESTTMP/repo
  
  incoming hook: HG_HOOKNAME=incoming
  HG_HOOKTYPE=incoming
  HG_NODE=9d18e5bd9ab09337802595d49f1dad0c98df4d84
  HG_PHASES_MOVED=1
  HG_SOURCE=pull
  HG_TXNID=TXN:$ID$
  HG_TXNNAME=pull
  file:/*/$TESTTMP/repo (glob)
  HG_URL=file:$TESTTMP/repo
  
  pullop.cgresult is -2
  (run 'hg update' to get a working copy)
  $ hg log -G
  o  9:9d18e5bd9ab0 public test  H
  |
  o    8:71bd7b46de72 public test  Merge
  |\
  | o  7:5cd59d311f65 public test  H
  | |
  o |  6:1d14c3ce6ac0 public test  G
  | |
  | | o  5:7f219660301f public test  F
  | | |
  +---o  4:8a5212ebc852 public test  E
  | |
  | o  3:b3325c91a4d9 public test  D
  | |
  | @  2:f838bfaca5c7 public test  C
  |/
  o  1:27547f69f254 public test  B
  |
  o  0:4a2df7238c3b public test  A
  

Test that "split" from inline content works fine (cf issue6811)
===============================================================

setup
-----

(create a compression free version where the split is easier to trigger)

  $ cat >> $HGRCPATH << EOF
  > [format]
  > revlog-compression=none
  > use-persistent-nodemap=no
  > EOF

  $ cd ..
  $ hg clone --pull repo repo-test-split --quiet
  pullop.cgresult is 2
  $ cat > repo-test-split/.hg/hgrc << EOF
  > [extensions]
  > bundle2=$TESTTMP/bundle2.py
  > EOF
  $ hg clone --pull repo-test-split clone-test-split --quiet
  pullop.cgresult is 2
  $ cd repo-test-split
  $ cat > .hg/hgrc << EOF
  > [extensions]
  > bundle2=$TESTTMP/bundle2.py
  > EOF


IMPORTANT: must be a non-split revlog with only a .i
  $ ls -1 .hg/store/00manifest.*
  .hg/store/00manifest.i
  $ ls -1 .hg/store/data/_a.*
  .hg/store/data/_a.i

  $ $TESTDIR/seq.py 100000 > A
  $ mkdir foo
  $ cd foo
  $ touch `$TESTDIR/seq.py 10000`
  $ cd ..
  $ hg add -q foo
  $ hg commit -m 'split the manifest and one filelog'


IMPORTANT: now the revlogs must be split
  $ ls -1 .hg/store/00manifest.*
  .hg/store/00manifest.d
  .hg/store/00manifest.i
  $ ls -1 .hg/store/data/_a.*
  .hg/store/data/_a.d
  .hg/store/data/_a.i

Add an extra commit on top of that

  $ echo foo >> A
  $ hg commit -m 'one extra commit'


Actual testing
--------------

  $ cd ../clone-test-split

We now pull this in the clone the split should be in one changegroup, the update in another one

  $ hg  pull
  pulling from $TESTTMP/repo-test-split
  searching for changes
  remote: changegroup1
  adding changesets
  adding manifests
  adding file changes
  remote: changegroup2
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 10002 changes to 10002 files
  new changesets 5e5bf9c91085:900b170f70d0
  pullop.cgresult is 1
  (run 'hg update' to get a working copy)

IMPORTANT: now the revlogs must be split
  $ ls -1 .hg/store/00manifest.*
  .hg/store/00manifest.d
  .hg/store/00manifest.i
  $ ls -1 .hg/store/data/_a.*
  .hg/store/data/_a.d
  .hg/store/data/_a.i

manifest should work

  $ hg  files -r tip | wc -l
  \s*10007 (re)

file content should work

  $ hg  cat -r tip A | wc -l
  \s*100001 (re)