view tests/test-bundle2-multiple-changegroups.t @ 26379:39d643252b9f

revlog: use existing file handle when reading during _addrevision

_addrevision() may need to read from revlogs as part of computing
deltas. Previously, we would flush existing file handles and open
a new, short-lived file handle to perform the reading.

If we have an existing file handle, it seems logical to reuse it
for reading instead of opening a new file handle. This patch
makes that the new behavior.

After this patch, revlog files are only reopened when adding
revisions if the revlog is switched from inline to non-inline.

On Linux when unbundling a bundle of the mozilla-central repo, this
patch has the following impact on system call counts:

Call     Before     After       Delta
write    827,639    673,390   -154,249
open     700,103    684,089    -16,014
read      74,489     74,489          0
fstat    493,924    461,896    -32,028
close    249,131    233,117    -16,014
stat     242,001    242,001          0
lstat     18,676     18,676          0
lseek     20,268     20,268          0
ioctl     14,652     13,173     -1,479
TOTAL  3,180,758  2,930,679   -250,079

It's worth noting that many of the open() calls fail due to missing
files. That's why there are many more open() calls than close().

Despite the significant system call reduction, this change does not
seem to have a significant performance impact on Linux.

On Windows 10 (not a VM, on a SSD), this patch appears to reduce
unbundle time for mozilla-central from ~960s to ~920s. This isn't
as significant as I was hoping. But a decrease it is nonetheless.
Still, Windows unbundle performance is still >2x slower than Linux.

Despite the lack of significant gains, fewer system calls is fewer
system calls. If nothing else, this will narrow the focus of potential
areas to optimize in the future.

Create an extension to test bundle2 with multiple changegroups

  $ cat > bundle2.py <<EOF
  > """
  > """
  > from mercurial import changegroup, 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]
  >     cg = changegroup.getchangegroup(repo, source, heads=intermediates,
  >                                      common=common, bundlecaps=bundlecaps)
  >     bundler.newpart('output', data='changegroup1')
  >     bundler.newpart('changegroup', data=cg.getchunks())
  >     cg = changegroup.getchangegroup(repo, source, heads=heads,
  >                                      common=common + intermediates,
  >                                      bundlecaps=bundlecaps)
  >     bundler.newpart('output', data='changegroup2')
  >     bundler.newpart('changegroup', data=cg.getchunks())
  > 
  > def _pull(repo, *args, **kwargs):
  >   pullop = _orig_pull(repo, *args, **kwargs)
  >   repo.ui.write('pullop.cgresult is %d\n' % pullop.cgresult)
  >   return pullop
  > 
  > _orig_pull = exchange.pull
  > exchange.pull = _pull
  > exchange.getbundle2partsmapping['changegroup'] = _getbundlechangegrouppart
  > EOF

  $ cat >> $HGRCPATH << EOF
  > [experimental]
  > bundle2-exp=True
  > [ui]
  > logtemplate={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 pretxnchangegroup"
  > changegroup = sh -c "printenv.py changegroup"
  > incoming = sh -c "printenv.py incoming"
  > EOF

Pull the new commits in the clone

  $ hg pull
  pulling from $TESTTMP/repo (glob)
  searching for changes
  remote: changegroup1
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  pretxnchangegroup hook: HG_NODE=27547f69f25460a52fff66ad004e58da7ad3fb56 HG_PENDING=$TESTTMP/clone HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=file:$TESTTMP/repo (glob)
  remote: changegroup2
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  pretxnchangegroup hook: HG_NODE=f838bfaca5c7226600ebcfd84f3c3c13a28d3757 HG_PENDING=$TESTTMP/clone HG_PHASES_MOVED=1 HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=file:$TESTTMP/repo (glob)
  changegroup hook: HG_NODE=27547f69f25460a52fff66ad004e58da7ad3fb56 HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=file:$TESTTMP/repo (glob)
  incoming hook: HG_NODE=27547f69f25460a52fff66ad004e58da7ad3fb56 HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=file:$TESTTMP/repo (glob)
  changegroup hook: HG_NODE=f838bfaca5c7226600ebcfd84f3c3c13a28d3757 HG_PHASES_MOVED=1 HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=file:$TESTTMP/repo (glob)
  incoming hook: HG_NODE=f838bfaca5c7226600ebcfd84f3c3c13a28d3757 HG_PHASES_MOVED=1 HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=file:$TESTTMP/repo (glob)
  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 $TESTTMP/repo (glob)
  searching for changes
  remote: changegroup1
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files (+1 heads)
  pretxnchangegroup hook: HG_NODE=b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e HG_PENDING=$TESTTMP/clone HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=file:$TESTTMP/repo (glob)
  remote: changegroup2
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 3 files (+1 heads)
  pretxnchangegroup hook: HG_NODE=7f219660301fe4c8a116f714df5e769695cc2b46 HG_PENDING=$TESTTMP/clone HG_PHASES_MOVED=1 HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=file:$TESTTMP/repo (glob)
  changegroup hook: HG_NODE=b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=file:$TESTTMP/repo (glob)
  incoming hook: HG_NODE=b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=file:$TESTTMP/repo (glob)
  incoming hook: HG_NODE=8a5212ebc8527f9fb821601504794e3eb11a1ed3 HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=file:$TESTTMP/repo (glob)
  changegroup hook: HG_NODE=7f219660301fe4c8a116f714df5e769695cc2b46 HG_PHASES_MOVED=1 HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=file:$TESTTMP/repo (glob)
  incoming hook: HG_NODE=7f219660301fe4c8a116f714df5e769695cc2b46 HG_PHASES_MOVED=1 HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=file:$TESTTMP/repo (glob)
  incoming hook: HG_NODE=1d14c3ce6ac0582d2809220d33e8cd7a696e0156 HG_PHASES_MOVED=1 HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=file:$TESTTMP/repo (glob)
  incoming hook: HG_NODE=5cd59d311f6508b8e0ed28a266756c859419c9f1 HG_PHASES_MOVED=1 HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=file:$TESTTMP/repo (glob)
  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 $TESTTMP/repo (glob)
  searching for changes
  remote: changegroup1
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 0 changes to 0 files (-1 heads)
  pretxnchangegroup hook: HG_NODE=71bd7b46de72e69a32455bf88d04757d542e6cf4 HG_PENDING=$TESTTMP/clone HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=file:$TESTTMP/repo (glob)
  remote: changegroup2
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  pretxnchangegroup hook: HG_NODE=9d18e5bd9ab09337802595d49f1dad0c98df4d84 HG_PENDING=$TESTTMP/clone HG_PHASES_MOVED=1 HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=file:$TESTTMP/repo (glob)
  changegroup hook: HG_NODE=71bd7b46de72e69a32455bf88d04757d542e6cf4 HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=file:$TESTTMP/repo (glob)
  incoming hook: HG_NODE=71bd7b46de72e69a32455bf88d04757d542e6cf4 HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=file:$TESTTMP/repo (glob)
  changegroup hook: HG_NODE=9d18e5bd9ab09337802595d49f1dad0c98df4d84 HG_PHASES_MOVED=1 HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=file:$TESTTMP/repo (glob)
  incoming hook: HG_NODE=9d18e5bd9ab09337802595d49f1dad0c98df4d84 HG_PHASES_MOVED=1 HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=file:$TESTTMP/repo (glob)
  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