view tests/test-issue4074.t @ 30146:148ccd1d9f2f

perf: add functions to get vfs-like object for Mercurial earlier than 2.3

Before this patch, using svfs prevents perf.py from measuring
performance of Mercurial earlier than 2.3 (or 7034365089bf), because
svfs isn't available in such Mercurial, even though there are some
code paths for Mercurial earlier than 2.3 in perf.py.

For example, setting "_prereadsize" attribute in perfindex() and
perfnodelookup() is effective only with hg earlier than 1.8 (or
61c9bc3da402).

To get appropriate vfs-like object to access files under .hg/store,
this patch adds getsvfs() (and also getvfs(), for future use).

To avoid examining existence of attribute at each repetition while
measuring performance, getsvfs() is invoked outside the function to be
called repeatedly.

This patch also adds check-perf-code.py an extra check entry to detect
direct usage of repo.(vfs|svfs|opener|sopener) in perf.py.

#require no-pure

A script to generate nasty diff worst-case scenarios:

  $ cat > s.py <<EOF
  > import random
  > for x in xrange(100000):
  >     print
  >     if random.randint(0, 100) >= 50:
  >         x += 1
  >     print hex(x)
  > EOF

  $ hg init a
  $ cd a

Check in a big file:

  $ python ../s.py > a
  $ hg ci -qAm0

Modify it:

  $ python ../s.py > a

Time a check-in, should never take more than 10 seconds user time:

  $ hg ci --time -m1
  time: real .* secs .user [0-9][.].* sys .* (re)