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.
$ hg debugextensions
$ debugpath=`pwd`/extwithoutinfos.py
$ cat > extwithoutinfos.py <<EOF
> EOF
$ cat >> $HGRCPATH <<EOF
> [extensions]
> color=
> histedit=
> patchbomb=
> rebase=
> mq=
> ext1 = $debugpath
> EOF
$ hg debugextensions
color
ext1 (untested!)
histedit
mq
patchbomb
rebase
$ hg debugextensions -v
color
location: */hgext/color.pyc (glob)
tested with: internal
ext1
location: */extwithoutinfos.pyc (glob)
histedit
location: */hgext/histedit.pyc (glob)
tested with: internal
mq
location: */hgext/mq.pyc (glob)
tested with: internal
patchbomb
location: */hgext/patchbomb.pyc (glob)
tested with: internal
rebase
location: */hgext/rebase.pyc (glob)
tested with: internal
$ hg debugextensions -Tjson | sed 's|\\\\|/|g'
[
{
"buglink": "",
"name": "color",
"source": "*/hgext/color.pyc", (glob)
"testedwith": "internal"
},
{
"buglink": "",
"name": "ext1",
"source": "*/extwithoutinfos.pyc", (glob)
"testedwith": ""
},
{
"buglink": "",
"name": "histedit",
"source": "*/hgext/histedit.pyc", (glob)
"testedwith": "internal"
},
{
"buglink": "",
"name": "mq",
"source": "*/hgext/mq.pyc", (glob)
"testedwith": "internal"
},
{
"buglink": "",
"name": "patchbomb",
"source": "*/hgext/patchbomb.pyc", (glob)
"testedwith": "internal"
},
{
"buglink": "",
"name": "rebase",
"source": "*/hgext/rebase.pyc", (glob)
"testedwith": "internal"
}
]