contrib/hgperf

revlog: don't use slicing to return parents

This is the only place we use a slice on index entries, which
are currently tuples. In preparation for moving away from tuples,
let's stop using slices so we don't have to implement that support
on the new type.

We also tweak the logic slightly so the exception only catches the
IndexError on the index lookup, not on the index entry lookup. The
old code should never have been buggy. But it was semantically wrong.

Differential Revision: https://phab.mercurial-scm.org/D1764

#!/usr/bin/env python
#
# hgperf - measure performance of Mercurial commands
#
# Copyright 2014 Matt Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

'''measure performance of Mercurial commands

Using ``hgperf`` instead of ``hg`` measures performance of the target
Mercurial command. For example, the execution below measures
performance of :hg:`heads --topo`::

    $ hgperf heads --topo

All command output via ``ui`` is suppressed, and just measurement
result is displayed: see also "perf" extension in "contrib".

Costs of processing before dispatching to the command function like
below are not measured::

    - parsing command line (e.g. option validity check)
    - reading configuration files in

But ``pre-`` and ``post-`` hook invocation for the target command is
measured, even though these are invoked before or after dispatching to
the command function, because these may be required to repeat
execution of the target command correctly.
'''

import os
import sys

libdir = '@LIBDIR@'

if libdir != '@' 'LIBDIR' '@':
    if not os.path.isabs(libdir):
        libdir = os.path.join(os.path.dirname(os.path.realpath(__file__)),
                              libdir)
        libdir = os.path.abspath(libdir)
    sys.path.insert(0, libdir)

# enable importing on demand to reduce startup time
try:
    from mercurial import demandimport; demandimport.enable()
except ImportError:
    import sys
    sys.stderr.write("abort: couldn't find mercurial libraries in [%s]\n" %
                     ' '.join(sys.path))
    sys.stderr.write("(check your install and PYTHONPATH)\n")
    sys.exit(-1)

from mercurial import (
    dispatch,
    util,
)

def timer(func, title=None):
    results = []
    begin = util.timer()
    count = 0
    while True:
        ostart = os.times()
        cstart = util.timer()
        r = func()
        cstop = util.timer()
        ostop = os.times()
        count += 1
        a, b = ostart, ostop
        results.append((cstop - cstart, b[0] - a[0], b[1]-a[1]))
        if cstop - begin > 3 and count >= 100:
            break
        if cstop - begin > 10 and count >= 3:
            break
    if title:
        sys.stderr.write("! %s\n" % title)
    if r:
        sys.stderr.write("! result: %s\n" % r)
    m = min(results)
    sys.stderr.write("! wall %f comb %f user %f sys %f (best of %d)\n"
                     % (m[0], m[1] + m[2], m[1], m[2], count))

orgruncommand = dispatch.runcommand

def runcommand(lui, repo, cmd, fullargs, ui, options, d, cmdpats, cmdoptions):
    ui.pushbuffer()
    lui.pushbuffer()
    timer(lambda : orgruncommand(lui, repo, cmd, fullargs, ui,
                                 options, d, cmdpats, cmdoptions))
    ui.popbuffer()
    lui.popbuffer()

dispatch.runcommand = runcommand

dispatch.run()