tests/test-annotate.py

perf: add threading capability to perfbdiff

Since we are releasing the GIL during diffing, it is interesting to see how a
thread pool would perform on diffing. We add a new `--threads` argument to
commands. Synchronizing the thread pool is a bit complex because we want to be
able to reuse it from one run to another.

On my computer (i7 with 4 cores + hyperthreading), I get the following data for
about 12000 revisions:
threads wall        comb    wall gain   comb overhead
none    31.596715   31.59    0.00%       0.00%
1       31.621228   31.62   -0.08%       0.09%
2       16.406202   32.8    48.08%       3.83%
3       11.598334   34.76   63.29%      10.03%
4        9.205421   36.77   70.87%      16.40%
5        8.517604   42.51   73.04%      34.57%
6        7.94645    47.58   74.85%      50.62%
7        7.434972   51.92   76.47%      64.36%
8        7.070638   55.34   77.62%      75.18%

Compared to the feature disabled (threads=0), the overhead is negligible with
the threading code (threads=1), and the gain is already 48% with two threads.

from __future__ import absolute_import
from __future__ import print_function

import unittest

from mercurial import (
    mdiff,
)
from mercurial.context import (
    annotateline,
    _annotatepair,
)

class AnnotateTests(unittest.TestCase):
    """Unit tests for annotate code."""

    def testannotatepair(self):
        self.maxDiff = None # camelcase-required

        oldfctx = b'old'
        p1fctx, p2fctx, childfctx = b'p1', b'p2', b'c'
        olddata = b'a\nb\n'
        p1data = b'a\nb\nc\n'
        p2data = b'a\nc\nd\n'
        childdata = b'a\nb2\nc\nc2\nd\n'
        diffopts = mdiff.diffopts()

        def decorate(text, rev):
            return ([annotateline(fctx=rev, lineno=i)
                     for i in xrange(1, text.count(b'\n') + 1)],
                    text)

        # Basic usage

        oldann = decorate(olddata, oldfctx)
        p1ann = decorate(p1data, p1fctx)
        p1ann = _annotatepair([oldann], p1fctx, p1ann, False, diffopts)
        self.assertEqual(p1ann[0], [
            annotateline('old', 1),
            annotateline('old', 2),
            annotateline('p1', 3),
        ])

        p2ann = decorate(p2data, p2fctx)
        p2ann = _annotatepair([oldann], p2fctx, p2ann, False, diffopts)
        self.assertEqual(p2ann[0], [
            annotateline('old', 1),
            annotateline('p2', 2),
            annotateline('p2', 3),
        ])

        # Test with multiple parents (note the difference caused by ordering)

        childann = decorate(childdata, childfctx)
        childann = _annotatepair([p1ann, p2ann], childfctx, childann, False,
                                 diffopts)
        self.assertEqual(childann[0], [
            annotateline('old', 1),
            annotateline('c', 2),
            annotateline('p2', 2),
            annotateline('c', 4),
            annotateline('p2', 3),
        ])

        childann = decorate(childdata, childfctx)
        childann = _annotatepair([p2ann, p1ann], childfctx, childann, False,
                                 diffopts)
        self.assertEqual(childann[0], [
            annotateline('old', 1),
            annotateline('c', 2),
            annotateline('p1', 3),
            annotateline('c', 4),
            annotateline('p2', 3),
        ])

        # Test with skipchild (note the difference caused by ordering)

        childann = decorate(childdata, childfctx)
        childann = _annotatepair([p1ann, p2ann], childfctx, childann, True,
                                 diffopts)
        self.assertEqual(childann[0], [
            annotateline('old', 1),
            annotateline('old', 2, True),
            # note that this line was carried over from earlier so it is *not*
            # marked skipped
            annotateline('p2', 2),
            annotateline('p2', 2, True),
            annotateline('p2', 3),
        ])

        childann = decorate(childdata, childfctx)
        childann = _annotatepair([p2ann, p1ann], childfctx, childann, True,
                                 diffopts)
        self.assertEqual(childann[0], [
            annotateline('old', 1),
            annotateline('old', 2, True),
            annotateline('p1', 3),
            annotateline('p1', 3, True),
            annotateline('p2', 3),
        ])

if __name__ == '__main__':
    import silenttestrunner
    silenttestrunner.main(__name__)