tests/test-walk.t

revlog: use an LRU cache for delta chain bases

Profiling using statprof revealed a hotspot during changegroup
application calculating delta chain bases on generaldelta repos.
Essentially, revlog._addrevision() was performing a lot of redundant
work tracing the delta chain as part of determining when the chain
distance was acceptable. This was most pronounced when adding
revisions to manifests, which can have delta chains thousands of
revisions long.

There was a delta chain base cache on revlogs before, but it only
captured a single revision. This was acceptable before generaldelta,
when _addrevision would build deltas from the previous revision and
thus we'd pretty much guarantee a cache hit when resolving the delta
chain base on a subsequent _addrevision call. However, it isn't
suitable for generaldelta because parent revisions aren't necessarily
the last processed revision.

This patch converts the delta chain base cache to an LRU dict cache.
The cache can hold multiple entries, so generaldelta repos have a
higher chance of getting a cache hit.

The impact of this change when processing changegroup additions is
significant. On a generaldelta conversion of the "mozilla-unified"
repo (which contains heads of the main Firefox repositories in
chronological order - this means there are lots of transitions between
heads in revlog order), this change has the following impact when
performing an `hg unbundle` of an uncompressed bundle of the repo:

before: 5:42 CPU time
after:  4:34 CPU time

Most of this time is saved when applying the changelog and manifest
revlogs:

before: 2:30 CPU time
after:  1:17 CPU time

That nearly a 50% reduction in CPU time applying changesets and
manifests!

Applying a gzipped bundle of the same repo (effectively simulating a
`hg clone` over HTTP) showed a similar speedup:

before: 5:53 CPU time
after:  4:46 CPU time

Wall time improvements were basically the same as CPU time.

I didn't measure explicitly, but it feels like most of the time
is saved when processing manifests. This makes sense, as large
manifests tend to have very long delta chains and thus benefit the
most from this cache.

So, this change effectively makes changegroup application (which is
used by `hg unbundle`, `hg clone`, `hg pull`, `hg unshelve`, and
various other commands) significantly faster when delta chains are
long (which can happen on repos with large numbers of files and thus
large manifests).

In theory, this change can result in more memory utilization. However,
we're caching a dict of ints. At most we have 200 ints + Python object
overhead per revlog. And, the cache is really only populated when
performing read-heavy operations, such as adding changegroups or
scanning an individual revlog. For memory bloat to be an issue, we'd
need to scan/read several revisions from several revlogs all while
having active references to several revlogs. I don't think there are
many operations that do this, so I don't think memory bloat from the
cache will be an issue.

  $ hg init t
  $ cd t
  $ mkdir -p beans
  $ for b in kidney navy turtle borlotti black pinto; do
  >     echo $b > beans/$b
  > done
  $ mkdir -p mammals/Procyonidae
  $ for m in cacomistle coatimundi raccoon; do
  >     echo $m > mammals/Procyonidae/$m
  > done
  $ echo skunk > mammals/skunk
  $ echo fennel > fennel
  $ echo fenugreek > fenugreek
  $ echo fiddlehead > fiddlehead
  $ hg addremove
  adding beans/black
  adding beans/borlotti
  adding beans/kidney
  adding beans/navy
  adding beans/pinto
  adding beans/turtle
  adding fennel
  adding fenugreek
  adding fiddlehead
  adding mammals/Procyonidae/cacomistle
  adding mammals/Procyonidae/coatimundi
  adding mammals/Procyonidae/raccoon
  adding mammals/skunk
  $ hg commit -m "commit #0"

  $ hg debugwalk
  f  beans/black                     beans/black
  f  beans/borlotti                  beans/borlotti
  f  beans/kidney                    beans/kidney
  f  beans/navy                      beans/navy
  f  beans/pinto                     beans/pinto
  f  beans/turtle                    beans/turtle
  f  fennel                          fennel
  f  fenugreek                       fenugreek
  f  fiddlehead                      fiddlehead
  f  mammals/Procyonidae/cacomistle  mammals/Procyonidae/cacomistle
  f  mammals/Procyonidae/coatimundi  mammals/Procyonidae/coatimundi
  f  mammals/Procyonidae/raccoon     mammals/Procyonidae/raccoon
  f  mammals/skunk                   mammals/skunk
  $ hg debugwalk -I.
  f  beans/black                     beans/black
  f  beans/borlotti                  beans/borlotti
  f  beans/kidney                    beans/kidney
  f  beans/navy                      beans/navy
  f  beans/pinto                     beans/pinto
  f  beans/turtle                    beans/turtle
  f  fennel                          fennel
  f  fenugreek                       fenugreek
  f  fiddlehead                      fiddlehead
  f  mammals/Procyonidae/cacomistle  mammals/Procyonidae/cacomistle
  f  mammals/Procyonidae/coatimundi  mammals/Procyonidae/coatimundi
  f  mammals/Procyonidae/raccoon     mammals/Procyonidae/raccoon
  f  mammals/skunk                   mammals/skunk

  $ cd mammals
  $ hg debugwalk
  f  beans/black                     ../beans/black
  f  beans/borlotti                  ../beans/borlotti
  f  beans/kidney                    ../beans/kidney
  f  beans/navy                      ../beans/navy
  f  beans/pinto                     ../beans/pinto
  f  beans/turtle                    ../beans/turtle
  f  fennel                          ../fennel
  f  fenugreek                       ../fenugreek
  f  fiddlehead                      ../fiddlehead
  f  mammals/Procyonidae/cacomistle  Procyonidae/cacomistle
  f  mammals/Procyonidae/coatimundi  Procyonidae/coatimundi
  f  mammals/Procyonidae/raccoon     Procyonidae/raccoon
  f  mammals/skunk                   skunk
  $ hg debugwalk -X ../beans
  f  fennel                          ../fennel
  f  fenugreek                       ../fenugreek
  f  fiddlehead                      ../fiddlehead
  f  mammals/Procyonidae/cacomistle  Procyonidae/cacomistle
  f  mammals/Procyonidae/coatimundi  Procyonidae/coatimundi
  f  mammals/Procyonidae/raccoon     Procyonidae/raccoon
  f  mammals/skunk                   skunk
  $ hg debugwalk -I '*k'
  f  mammals/skunk  skunk
  $ hg debugwalk -I 'glob:*k'
  f  mammals/skunk  skunk
  $ hg debugwalk -I 'relglob:*k'
  f  beans/black    ../beans/black
  f  fenugreek      ../fenugreek
  f  mammals/skunk  skunk
  $ hg debugwalk -I 'relglob:*k' .
  f  mammals/skunk  skunk
  $ hg debugwalk -I 're:.*k$'
  f  beans/black    ../beans/black
  f  fenugreek      ../fenugreek
  f  mammals/skunk  skunk
  $ hg debugwalk -I 'relre:.*k$'
  f  beans/black    ../beans/black
  f  fenugreek      ../fenugreek
  f  mammals/skunk  skunk
  $ hg debugwalk -I 'path:beans'
  f  beans/black     ../beans/black
  f  beans/borlotti  ../beans/borlotti
  f  beans/kidney    ../beans/kidney
  f  beans/navy      ../beans/navy
  f  beans/pinto     ../beans/pinto
  f  beans/turtle    ../beans/turtle
  $ hg debugwalk -I 'relpath:detour/../../beans'
  f  beans/black     ../beans/black
  f  beans/borlotti  ../beans/borlotti
  f  beans/kidney    ../beans/kidney
  f  beans/navy      ../beans/navy
  f  beans/pinto     ../beans/pinto
  f  beans/turtle    ../beans/turtle
  $ hg debugwalk .
  f  mammals/Procyonidae/cacomistle  Procyonidae/cacomistle
  f  mammals/Procyonidae/coatimundi  Procyonidae/coatimundi
  f  mammals/Procyonidae/raccoon     Procyonidae/raccoon
  f  mammals/skunk                   skunk
  $ hg debugwalk -I.
  f  mammals/Procyonidae/cacomistle  Procyonidae/cacomistle
  f  mammals/Procyonidae/coatimundi  Procyonidae/coatimundi
  f  mammals/Procyonidae/raccoon     Procyonidae/raccoon
  f  mammals/skunk                   skunk
  $ hg debugwalk Procyonidae
  f  mammals/Procyonidae/cacomistle  Procyonidae/cacomistle
  f  mammals/Procyonidae/coatimundi  Procyonidae/coatimundi
  f  mammals/Procyonidae/raccoon     Procyonidae/raccoon

  $ cd Procyonidae
  $ hg debugwalk .
  f  mammals/Procyonidae/cacomistle  cacomistle
  f  mammals/Procyonidae/coatimundi  coatimundi
  f  mammals/Procyonidae/raccoon     raccoon
  $ hg debugwalk ..
  f  mammals/Procyonidae/cacomistle  cacomistle
  f  mammals/Procyonidae/coatimundi  coatimundi
  f  mammals/Procyonidae/raccoon     raccoon
  f  mammals/skunk                   ../skunk
  $ cd ..

  $ hg debugwalk ../beans
  f  beans/black     ../beans/black
  f  beans/borlotti  ../beans/borlotti
  f  beans/kidney    ../beans/kidney
  f  beans/navy      ../beans/navy
  f  beans/pinto     ../beans/pinto
  f  beans/turtle    ../beans/turtle
  $ hg debugwalk .
  f  mammals/Procyonidae/cacomistle  Procyonidae/cacomistle
  f  mammals/Procyonidae/coatimundi  Procyonidae/coatimundi
  f  mammals/Procyonidae/raccoon     Procyonidae/raccoon
  f  mammals/skunk                   skunk
  $ hg debugwalk .hg
  abort: path 'mammals/.hg' is inside nested repo 'mammals' (glob)
  [255]
  $ hg debugwalk ../.hg
  abort: path contains illegal component: .hg
  [255]
  $ cd ..

  $ hg debugwalk -Ibeans
  f  beans/black     beans/black
  f  beans/borlotti  beans/borlotti
  f  beans/kidney    beans/kidney
  f  beans/navy      beans/navy
  f  beans/pinto     beans/pinto
  f  beans/turtle    beans/turtle
  $ hg debugwalk -I '{*,{b,m}*/*}k'
  f  beans/black    beans/black
  f  fenugreek      fenugreek
  f  mammals/skunk  mammals/skunk
  $ hg debugwalk -Ibeans mammals
  $ hg debugwalk -Inon-existent
  $ hg debugwalk -Inon-existent -Ibeans/black
  f  beans/black  beans/black
  $ hg debugwalk -Ibeans beans/black
  f  beans/black  beans/black  exact
  $ hg debugwalk -Ibeans/black beans
  f  beans/black  beans/black
  $ hg debugwalk -Xbeans/black beans
  f  beans/borlotti  beans/borlotti
  f  beans/kidney    beans/kidney
  f  beans/navy      beans/navy
  f  beans/pinto     beans/pinto
  f  beans/turtle    beans/turtle
  $ hg debugwalk -Xbeans/black -Ibeans
  f  beans/borlotti  beans/borlotti
  f  beans/kidney    beans/kidney
  f  beans/navy      beans/navy
  f  beans/pinto     beans/pinto
  f  beans/turtle    beans/turtle
  $ hg debugwalk -Xbeans/black beans/black
  f  beans/black  beans/black  exact
  $ hg debugwalk -Xbeans/black -Ibeans/black
  $ hg debugwalk -Xbeans beans/black
  f  beans/black  beans/black  exact
  $ hg debugwalk -Xbeans -Ibeans/black
  $ hg debugwalk 'glob:mammals/../beans/b*'
  f  beans/black     beans/black
  f  beans/borlotti  beans/borlotti
  $ hg debugwalk '-X*/Procyonidae' mammals
  f  mammals/skunk  mammals/skunk
  $ hg debugwalk path:mammals
  f  mammals/Procyonidae/cacomistle  mammals/Procyonidae/cacomistle
  f  mammals/Procyonidae/coatimundi  mammals/Procyonidae/coatimundi
  f  mammals/Procyonidae/raccoon     mammals/Procyonidae/raccoon
  f  mammals/skunk                   mammals/skunk
  $ hg debugwalk ..
  abort: .. not under root '$TESTTMP/t' (glob)
  [255]
  $ hg debugwalk beans/../..
  abort: beans/../.. not under root '$TESTTMP/t' (glob)
  [255]
  $ hg debugwalk .hg
  abort: path contains illegal component: .hg
  [255]
  $ hg debugwalk beans/../.hg
  abort: path contains illegal component: .hg
  [255]
  $ hg debugwalk beans/../.hg/data
  abort: path contains illegal component: .hg/data (glob)
  [255]
  $ hg debugwalk beans/.hg
  abort: path 'beans/.hg' is inside nested repo 'beans' (glob)
  [255]

Test absolute paths:

  $ hg debugwalk `pwd`/beans
  f  beans/black     beans/black
  f  beans/borlotti  beans/borlotti
  f  beans/kidney    beans/kidney
  f  beans/navy      beans/navy
  f  beans/pinto     beans/pinto
  f  beans/turtle    beans/turtle
  $ hg debugwalk `pwd`/..
  abort: $TESTTMP/t/.. not under root '$TESTTMP/t' (glob)
  [255]

Test patterns:

  $ hg debugwalk glob:\*
  f  fennel      fennel
  f  fenugreek   fenugreek
  f  fiddlehead  fiddlehead
#if eol-in-paths
  $ echo glob:glob > glob:glob
  $ hg addremove
  adding glob:glob
  warning: filename contains ':', which is reserved on Windows: 'glob:glob'
  $ hg debugwalk glob:\*
  f  fennel      fennel
  f  fenugreek   fenugreek
  f  fiddlehead  fiddlehead
  f  glob:glob   glob:glob
  $ hg debugwalk glob:glob
  glob: No such file or directory
  $ hg debugwalk glob:glob:glob
  f  glob:glob  glob:glob  exact
  $ hg debugwalk path:glob:glob
  f  glob:glob  glob:glob  exact
  $ rm glob:glob
  $ hg addremove
  removing glob:glob
#endif

  $ hg debugwalk 'glob:**e'
  f  beans/turtle                    beans/turtle
  f  mammals/Procyonidae/cacomistle  mammals/Procyonidae/cacomistle

  $ hg debugwalk 're:.*[kb]$'
  f  beans/black    beans/black
  f  fenugreek      fenugreek
  f  mammals/skunk  mammals/skunk

  $ hg debugwalk path:beans/black
  f  beans/black  beans/black  exact
  $ hg debugwalk path:beans//black
  f  beans/black  beans/black  exact

  $ hg debugwalk relglob:Procyonidae
  $ hg debugwalk 'relglob:Procyonidae/**'
  f  mammals/Procyonidae/cacomistle  mammals/Procyonidae/cacomistle
  f  mammals/Procyonidae/coatimundi  mammals/Procyonidae/coatimundi
  f  mammals/Procyonidae/raccoon     mammals/Procyonidae/raccoon
  $ hg debugwalk 'relglob:Procyonidae/**' fennel
  f  fennel                          fennel                          exact
  f  mammals/Procyonidae/cacomistle  mammals/Procyonidae/cacomistle
  f  mammals/Procyonidae/coatimundi  mammals/Procyonidae/coatimundi
  f  mammals/Procyonidae/raccoon     mammals/Procyonidae/raccoon
  $ hg debugwalk beans 'glob:beans/*'
  f  beans/black     beans/black
  f  beans/borlotti  beans/borlotti
  f  beans/kidney    beans/kidney
  f  beans/navy      beans/navy
  f  beans/pinto     beans/pinto
  f  beans/turtle    beans/turtle
  $ hg debugwalk 'glob:mamm**'
  f  mammals/Procyonidae/cacomistle  mammals/Procyonidae/cacomistle
  f  mammals/Procyonidae/coatimundi  mammals/Procyonidae/coatimundi
  f  mammals/Procyonidae/raccoon     mammals/Procyonidae/raccoon
  f  mammals/skunk                   mammals/skunk
  $ hg debugwalk 'glob:mamm**' fennel
  f  fennel                          fennel                          exact
  f  mammals/Procyonidae/cacomistle  mammals/Procyonidae/cacomistle
  f  mammals/Procyonidae/coatimundi  mammals/Procyonidae/coatimundi
  f  mammals/Procyonidae/raccoon     mammals/Procyonidae/raccoon
  f  mammals/skunk                   mammals/skunk
  $ hg debugwalk 'glob:j*'
  $ hg debugwalk NOEXIST
  NOEXIST: * (glob)

#if fifo
  $ mkfifo fifo
  $ hg debugwalk fifo
  fifo: unsupported file type (type is fifo)
#endif

  $ rm fenugreek
  $ hg debugwalk fenugreek
  f  fenugreek  fenugreek  exact
  $ hg rm fenugreek
  $ hg debugwalk fenugreek
  f  fenugreek  fenugreek  exact
  $ touch new
  $ hg debugwalk new
  f  new  new  exact

  $ mkdir ignored
  $ touch ignored/file
  $ echo '^ignored$' > .hgignore
  $ hg debugwalk ignored
  $ hg debugwalk ignored/file
  f  ignored/file  ignored/file  exact

Test listfile and listfile0

  $ $PYTHON -c "file('listfile0', 'wb').write('fenugreek\0new\0')"
  $ hg debugwalk -I 'listfile0:listfile0'
  f  fenugreek  fenugreek
  f  new        new
  $ $PYTHON -c "file('listfile', 'wb').write('fenugreek\nnew\r\nmammals/skunk\n')"
  $ hg debugwalk -I 'listfile:listfile'
  f  fenugreek      fenugreek
  f  mammals/skunk  mammals/skunk
  f  new            new

  $ cd ..
  $ hg debugwalk -R t t/mammals/skunk
  f  mammals/skunk  t/mammals/skunk  exact
  $ mkdir t2
  $ cd t2
  $ hg debugwalk -R ../t ../t/mammals/skunk
  f  mammals/skunk  ../t/mammals/skunk  exact
  $ hg debugwalk --cwd ../t mammals/skunk
  f  mammals/skunk  mammals/skunk  exact

  $ cd ..

Test split patterns on overflow

  $ cd t
  $ echo fennel > overflow.list
  $ $PYTHON -c "for i in xrange(20000 / 100): print 'x' * 100" >> overflow.list
  $ echo fenugreek >> overflow.list
  $ hg debugwalk 'listfile:overflow.list' 2>&1 | grep -v '^xxx'
  f  fennel     fennel     exact
  f  fenugreek  fenugreek  exact
  $ cd ..