tests/test-profile.t

log: speed up single file log with hidden revs (issue4747)

On repos with lots of heads, the filelog() code could spend several
minutes decompressing manifests. This change instead tries to
efficiently scan the changelog for candidates and decompress as few
manifests as possible. This is a regression introduced in 3.3 by the
linkrev adjustment code. Prior to that, filelog was nearly instant.

For the repo in the bug report, this improves time of a simple log
command from ~3 minutes to ~.5 seconds, a 360x speedup.

For the main Mercurial repo, a log of commands.py slows down from
1.14s to 1.45s, a 27% slowdown. This is still faster than the file()
revset, which takes 2.1 seconds.

test --time

  $ hg --time help -q help 2>&1 | grep time > /dev/null
  $ hg init a
  $ cd a

#if lsprof

test --profile

  $ hg --profile st 2>../out
  $ grep CallCount ../out > /dev/null || cat ../out

  $ hg --profile --config profiling.output=../out st
  $ grep CallCount ../out > /dev/null || cat ../out

  $ hg --profile --config profiling.output=blackbox --config extensions.blackbox= st
  $ grep CallCount .hg/blackbox.log > /dev/null || cat .hg/blackbox.log

  $ hg --profile --config profiling.format=text st 2>../out
  $ grep CallCount ../out > /dev/null || cat ../out

  $ echo "[profiling]" >> $HGRCPATH
  $ echo "format=kcachegrind" >> $HGRCPATH

  $ hg --profile st 2>../out
  $ grep 'events: Ticks' ../out > /dev/null || cat ../out

  $ hg --profile --config profiling.output=../out st
  $ grep 'events: Ticks' ../out > /dev/null || cat ../out

#endif

  $ cd ..