contrib/hgperf

windows: allow readpipe() to actually read data out of the pipe

It appears that the read() in readpipe() never actually ran before (in
test-ssh.t anyway).  A print of the size returned from os.fstat() is 0 for every
single print output in test-ssh.t, so the data in the pipe ends up being read
later instead of when it is available.  This is the same problem as Linux, as
mentioned in 331cbf088c4c.

There are several places in the Windows SSH tests where the order of local
output vs remote output differ from the other platforms.  This only fixes one of
those cases (and interstingly, not the one added in order to test 331cbf088c4c),
so there is more investigation needed.  However, without this patch, test-ssh.t
also has this diff:

    --- c:/Users/Matt/Projects/hg/tests/test-ssh.t
    +++ c:/Users/Matt/Projects/hg/tests/test-ssh.t.err
    @@ -397,11 +397,11 @@
       $ hg push --ssh "sh ../ssh.sh"
       pushing to ssh://user@dummy/*/remote (glob)
       searching for changes
    -  remote: Permission denied
    -  remote: abort: prechangegroup.hg-ssh hook failed
    -  remote: Permission denied
    -  remote: pushkey-abort: prepushkey.hg-ssh hook failed
       updating 6c0482d977a3 to public failed!
    +  remote: Permission denied
    +  remote: abort: prechangegroup.hg-ssh hook failed
    +  remote: Permission denied
    +  remote: pushkey-abort: prepushkey.hg-ssh hook failed
       [1]

       $ cd ..

Output with this change was stable over 600+ runs of test-ssh.t.  I initially
tried a background thread to read the pipe[1], but this was simpler and the test
results were exactly the same.  I also tried SetNamedPipeHandleState(), but the
PIPE_NOWAIT is for compatibility with LANMAN 2.0, not for async I/O (the results
were identical though).

[1] http://eyalarubas.com/python-subproc-nonblock.html

#!/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)

import mercurial.util
import mercurial.dispatch

import time

def timer(func, title=None):
    results = []
    begin = time.time()
    count = 0
    while True:
        ostart = os.times()
        cstart = time.time()
        r = func()
        cstop = time.time()
        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 = mercurial.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()

mercurial.dispatch.runcommand = runcommand

for fp in (sys.stdin, sys.stdout, sys.stderr):
    mercurial.util.setbinary(fp)

mercurial.dispatch.run()