contrib/hgperf

exchange: improve computation of relevant markers for large repos

Compute the candidate nodes with relevant markers directly
from keys of the predecessors/successors/children dictionaries of
obsstore. This is faster than iterating over all nodes directly.
This test could be further improved for repositories with relative
few markers compared to the repository size, but this is no longer
hot already. With the current loop structure, the obshashrange use
works as well as before as it passes lists with a single node.

Adjust the interface by allowing revision lists as well as node lists.
This helps cases that computes ancestors as it reduces the
materialisation cost. Use this in _pushdiscoveryobsmarker and
_getbundleobsmarkerpart. Improve the latter further by directly using
ancestors().


Performance benchmarks show notable and welcome improvement to no-op push and
pull (that would also apply to other push/pull). This apply to push and pull
done without evolve.

### push/pull Benchmark parameter
  # bin-env-vars.hg.flavor          = default
  # benchmark.variants.explicit-rev = none
  # benchmark.variants.protocol     = ssh
  # benchmark.variants.revs         = none

 ## benchmark.name                  = hg.command.pull
  # data-env-vars.name              = mercurial-devel-2024-03-22-zstd-sparse-revlog
before: 5.968537 seconds
after:  5.668507 seconds (-5.03%, -0.30)
  # data-env-vars.name              = tryton-devel-2024-03-22-zstd-sparse-revlog
before: 1.446232 seconds
after:  0.835553 seconds (-42.23%, -0.61)
  # data-env-vars.name              = netbsd-src-draft-2024-09-19-zstd-sparse-revlog
before: 5.777412 seconds
after:  2.523454 seconds (-56.32%, -3.25)

 ## benchmark.name                  = hg.command.push
  # data-env-vars.name              = mercurial-devel-2024-03-22-zstd-sparse-revlog
before: 6.155501 seconds
after:  5.885072 seconds (-4.39%, -0.27)

  # data-env-vars.name              = tryton-devel-2024-03-22-zstd-sparse-revlog
before: 1.491054 seconds
after:  0.934882 seconds (-37.30%, -0.56)

  # data-env-vars.name              = netbsd-src-draft-2024-09-19-zstd-sparse-revlog
before: 5.902494 seconds
after:  2.957644 seconds (-49.89%, -2.94)

There is not notable different in these result using the "rust" flavor instead
of the "default".  The performance impact on the same operation when using
evolve were also tested and no impact was noted.

#!/usr/bin/env python3
#
# hgperf - measure performance of Mercurial commands
#
# Copyright 2014 Olivia 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()