view tests/test-convert-cvsnt-mergepoints.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

#require cvs

  $ filterpath()
  > {
  >     eval "$@" | sed "s:$CVSROOT:*REPO*:g"
  > }
  $ cvscall()
  > {
  >     cvs -f "$@"
  > }

output of 'cvs ci' varies unpredictably, so discard most of it
-- just keep the part that matters

  $ cvsci()
  > {
  >     cvs -f ci -f "$@" > /dev/null
  > }
  $ hgcat()
  > {
  >     hg --cwd src-hg cat -r tip "$1"
  > }
  $ echo "[extensions]" >> $HGRCPATH
  $ echo "convert = " >> $HGRCPATH

create cvs repository

  $ mkdir cvsmaster
  $ cd cvsmaster
  $ CVSROOT=`pwd`
  $ export CVSROOT
  $ CVS_OPTIONS=-f
  $ export CVS_OPTIONS
  $ cd ..
  $ rmdir cvsmaster
  $ filterpath cvscall -Q -d "$CVSROOT" init

checkout #1: add foo.txt

  $ cvscall -Q checkout -d cvsworktmp .
  $ cd cvsworktmp
  $ mkdir foo
  $ cvscall -Q add foo
  $ cd foo
  $ echo foo > foo.txt
  $ cvscall -Q add foo.txt
  $ cvsci -m "add foo.txt" foo.txt
  $ cd ../..
  $ rm -rf cvsworktmp

checkout #2: create MYBRANCH1 and modify foo.txt on it

  $ cvscall -Q checkout -d cvswork foo
  $ cd cvswork
  $ cvscall -q rtag -b -R MYBRANCH1 foo
  $ cvscall -Q update -P -r MYBRANCH1
  $ echo bar > foo.txt
  $ cvsci -m "bar" foo.txt
  $ echo baz > foo.txt
  $ cvsci -m "baz" foo.txt

create MYBRANCH1_2 and modify foo.txt some more

  $ cvscall -q rtag -b -R -r MYBRANCH1 MYBRANCH1_2 foo
  $ cvscall -Q update -P -r MYBRANCH1_2
  $ echo bazzie > foo.txt
  $ cvsci -m "bazzie" foo.txt

create MYBRANCH1_1 and modify foo.txt yet again

  $ cvscall -q rtag -b -R MYBRANCH1_1 foo
  $ cvscall -Q update -P -r MYBRANCH1_1
  $ echo quux > foo.txt
  $ cvsci -m "quux" foo.txt

merge MYBRANCH1 to MYBRANCH1_1

  $ filterpath cvscall -Q update -P -jMYBRANCH1
  rcsmerge: warning: conflicts during merge
  RCS file: *REPO*/foo/foo.txt,v
  retrieving revision 1.1
  retrieving revision 1.1.2.2
  Merging differences between 1.1 and 1.1.2.2 into foo.txt

carefully placed sleep to dodge cvs bug (optimization?) where it
sometimes ignores a "commit" command if it comes too fast (the -f
option in cvsci seems to work for all the other commits in this
script)

  $ sleep 1
  $ echo xyzzy > foo.txt
  $ cvsci -m "merge1+clobber" foo.txt

#if unix-permissions

return to trunk and merge MYBRANCH1_2

  $ cvscall -Q update -P -A
  $ filterpath cvscall -Q update -P -jMYBRANCH1_2
  RCS file: *REPO*/foo/foo.txt,v
  retrieving revision 1.1
  retrieving revision 1.1.2.2.2.1
  Merging differences between 1.1 and 1.1.2.2.2.1 into foo.txt
  $ cvsci -m "merge2" foo.txt
  $ REALCVS=`which cvs`
  $ echo "for x in \$*; do if [ \"\$x\" = \"rlog\" ]; then echo \"RCS file: $CVSROOT/foo/foo.txt,v\"; cat \"$TESTDIR/test-convert-cvsnt-mergepoints.rlog\"; exit 0; fi; done; $REALCVS \$*" > ../cvs
  $ chmod +x ../cvs
  $ PATH=..:${PATH} hg debugcvsps --parents foo
  collecting CVS rlog
  7 log entries
  creating changesets
  7 changeset entries
  ---------------------
  PatchSet 1 
  Date: * (glob)
  Author: user
  Branch: HEAD
  Tag: (none) 
  Branchpoints: MYBRANCH1, MYBRANCH1_1 
  Log:
  foo.txt
  
  Members: 
  	foo.txt:INITIAL->1.1 
  
  ---------------------
  PatchSet 2 
  Date: * (glob)
  Author: user
  Branch: MYBRANCH1
  Tag: (none) 
  Parent: 1
  Log:
  bar
  
  Members: 
  	foo.txt:1.1->1.1.2.1 
  
  ---------------------
  PatchSet 3 
  Date: * (glob)
  Author: user
  Branch: MYBRANCH1
  Tag: (none) 
  Branchpoints: MYBRANCH1_2 
  Parent: 2
  Log:
  baz
  
  Members: 
  	foo.txt:1.1.2.1->1.1.2.2 
  
  ---------------------
  PatchSet 4 
  Date: * (glob)
  Author: user
  Branch: MYBRANCH1_1
  Tag: (none) 
  Parent: 1
  Log:
  quux
  
  Members: 
  	foo.txt:1.1->1.1.4.1 
  
  ---------------------
  PatchSet 5 
  Date: * (glob)
  Author: user
  Branch: MYBRANCH1_2
  Tag: (none) 
  Parent: 3
  Log:
  bazzie
  
  Members: 
  	foo.txt:1.1.2.2->1.1.2.2.2.1 
  
  ---------------------
  PatchSet 6 
  Date: * (glob)
  Author: user
  Branch: HEAD
  Tag: (none) 
  Parents: 1,5
  Log:
  merge
  
  Members: 
  	foo.txt:1.1->1.2 
  
  ---------------------
  PatchSet 7 
  Date: * (glob)
  Author: user
  Branch: MYBRANCH1_1
  Tag: (none) 
  Parents: 4,3
  Log:
  merge
  
  Members: 
  	foo.txt:1.1.4.1->1.1.4.2 
  
#endif

  $ cd ..