Mercurial > hg-stable
view hg @ 45773:210f9b8d7bbd stable
diff: do not concatenate immutable bytes while building a/b bodies (issue6445)
Use bytearray instead. I don't know what's changed since Python 2, but bytes
concatenation is 100x slow on Python 3.
% python2.7 -m timeit -s "s = b''" "for i in range(10000): s += b'line'"
1000 loops, best of 3: 321 usec per loop
% python3.9 -m timeit -s "s = b''" "for i in range(10000): s += b'line'"
5 loops, best of 5: 39.2 msec per loop
Benchmark using tailwind.css (measuring the fast path, a is empty):
% HGRCPATH=/dev/null python2.7 ./hg log -R /tmp/issue6445 -p --time \
--color=always --config diff.word-diff=true >/dev/null
(prev) time: real 1.580 secs (user 1.560+0.000 sys 0.020+0.000)
(this) time: real 1.610 secs (user 1.570+0.000 sys 0.030+0.000)
% HGRCPATH=/dev/null python3.9 ./hg log -R /tmp/issue6445 -p --time \
--color=always --config diff.word-diff=true >/dev/null
(prev) time: real 114.500 secs (user 114.460+0.000 sys 0.030+0.000)
(this) time: real 2.180 secs (user 2.140+0.000 sys 0.040+0.000)
Benchmark using random tabular text data (not the fast path):
% dd if=/dev/urandom bs=1k count=1000 | hexdump -v -e '16/1 "%3u," "\n"' > ttf
% hg ci -ma
% dd if=/dev/urandom bs=1k count=1000 | hexdump -v -e '16/1 "%3u," "\n"' > ttf
% hg ci -mb
% HGRCPATH=/dev/null python2.7 ./hg log -R /tmp/issue6445 -p --time \
--color=always --config diff.word-diff=true >/dev/null
(prev) time: real 3.240 secs (user 3.040+0.000 sys 0.200+0.000
(this) time: real 3.230 secs (user 3.070+0.000 sys 0.160+0.000)
% HGRCPATH=/dev/null python3.9 ./hg log -R /tmp/issue6445 -p --time \
--color=always --config diff.word-diff=true >/dev/null
(prev) time: real 44.130 secs (user 43.850+0.000 sys 0.270+0.000)
(this) time: real 4.170 secs (user 3.850+0.000 sys 0.310+0.000)
author | Yuya Nishihara <yuya@tcha.org> |
---|---|
date | Sat, 28 Nov 2020 11:15:54 +0900 |
parents | 99e231afc29c |
children | c102b704edb5 |
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#!/usr/bin/env python # # mercurial - scalable distributed SCM # # Copyright 2005-2007 Matt Mackall <mpm@selenic.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import 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) from hgdemandimport import tracing with tracing.log('hg script'): # enable importing on demand to reduce startup time try: if sys.version_info[0] < 3 or sys.version_info >= (3, 6): import hgdemandimport hgdemandimport.enable() except ImportError: 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 dispatch.run()