perf: add perfrevlogrevision
As part of investigating performance improvements to revlog reading,
I needed a mechanism to measure every part of revlog reading so I knew
where time was spent and how effective optimizations were.
This patch implements a perf command for benchmarking the various
stages of reading a single revlog revision.
When executed against a manifest revision at the end of a 30,000+
long delta chain in mozilla-central, the command demonstrates that
~80% of time is spent in zlib decompression.
# extension to emulate invoking 'patch.internalpatch()' at the time
# specified by '[fakepatchtime] fakenow'
from __future__ import absolute_import
from mercurial import (
extensions,
patch as patchmod,
util,
)
def internalpatch(orig, ui, repo, patchobj, strip,
prefix='', files=None,
eolmode='strict', similarity=0):
if files is None:
files = set()
r = orig(ui, repo, patchobj, strip,
prefix=prefix, files=files,
eolmode=eolmode, similarity=similarity)
fakenow = ui.config('fakepatchtime', 'fakenow')
if fakenow:
# parsing 'fakenow' in YYYYmmddHHMM format makes comparison between
# 'fakenow' value and 'touch -t YYYYmmddHHMM' argument easy
fakenow = util.parsedate(fakenow, ['%Y%m%d%H%M'])[0]
for f in files:
repo.wvfs.utime(f, (fakenow, fakenow))
return r
def extsetup(ui):
extensions.wrapfunction(patchmod, 'internalpatch', internalpatch)