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.
# debugshell extension
"""a python shell with repo, changelog & manifest objects"""
import sys
import mercurial
import code
from mercurial import cmdutil
cmdtable = {}
command = cmdutil.command(cmdtable)
def pdb(ui, repo, msg, **opts):
objects = {
'mercurial': mercurial,
'repo': repo,
'cl': repo.changelog,
'mf': repo.manifest,
}
code.interact(msg, local=objects)
def ipdb(ui, repo, msg, **opts):
import IPython
cl = repo.changelog
mf = repo.manifest
cl, mf # use variables to appease pyflakes
IPython.embed()
@command('debugshell|dbsh', [])
def debugshell(ui, repo, **opts):
bannermsg = "loaded repo : %s\n" \
"using source: %s" % (repo.root,
mercurial.__path__[0])
pdbmap = {
'pdb' : 'code',
'ipdb' : 'IPython'
}
debugger = ui.config("ui", "debugger")
if not debugger:
debugger = 'pdb'
# if IPython doesn't exist, fallback to code.interact
try:
__import__(pdbmap[debugger])
except ImportError:
ui.warn("%s debugger specified but %s module was not found\n"
% (debugger, pdbmap[debugger]))
debugger = 'pdb'
getattr(sys.modules[__name__], debugger)(ui, repo, bannermsg, **opts)