git-commit-vandalism/t/perf/p7820-grep-engines.sh
Ævar Arnfjörð Bjarmason 3878c7a540 perf: add a comparison test of grep regex engines
Add a very basic performance comparison test comparing the POSIX
basic, extended and perl engines.

In theory the "basic" and "extended" engines should be implemented
using the same underlying code with a slightly different pattern
parser, but some implementations may not do this. Jump through some
slight hoops to test both, which is worthwhile since "basic" is the
default.

Running this on an i7 3.4GHz Linux 4.9.0-2 Debian testing against a
checkout of linux.git & latest upstream PCRE, both PCRE and git
compiled with -O3 using gcc 7.1.1:

    $ GIT_PERF_REPEAT_COUNT=10 GIT_PERF_LARGE_REPO=~/g/linux ./run p7820-grep-engines.sh
    [...]
    Test                                            this tree
    ---------------------------------------------------------------
    7820.1: basic grep 'how.to'                     0.34(1.24+0.53)
    7820.2: extended grep 'how.to'                  0.33(1.23+0.45)
    7820.3: perl grep 'how.to'                      0.31(1.05+0.56)
    7820.5: basic grep '^how to'                    0.32(1.24+0.42)
    7820.6: extended grep '^how to'                 0.33(1.20+0.44)
    7820.7: perl grep '^how to'                     0.57(2.67+0.42)
    7820.9: basic grep '[how] to'                   0.51(2.16+0.45)
    7820.10: extended grep '[how] to'               0.49(2.20+0.43)
    7820.11: perl grep '[how] to'                   0.56(2.60+0.43)
    7820.13: basic grep '\(e.t[^ ]*\|v.ry\) rare'   0.66(3.25+0.40)
    7820.14: extended grep '(e.t[^ ]*|v.ry) rare'   0.65(3.19+0.46)
    7820.15: perl grep '(e.t[^ ]*|v.ry) rare'       1.05(5.74+0.34)
    7820.17: basic grep 'm\(ú\|u\)lt.b\(æ\|y\)te'   0.34(1.28+0.47)
    7820.18: extended grep 'm(ú|u)lt.b(æ|y)te'      0.34(1.38+0.38)
    7820.19: perl grep 'm(ú|u)lt.b(æ|y)te'          0.39(1.56+0.44)

Options can also be passed to git-grep via the GIT_PERF_7820_GREP_OPTS
environment variable. There are various modes such as "-v" that have
very different performance profiles, but handling the combinatorial
explosion of testing all those options would make this script much
more complex and harder to maintain. Instead just add the ability to
do one-shot runs with arbitrary options, e.g.:

    $ GIT_PERF_REPEAT_COUNT=10 GIT_PERF_LARGE_REPO=~/g/linux GIT_PERF_7820_GREP_OPTS=" -i" ./run p7820-grep-engines.sh
    [...]
    Test                                               this tree
    ------------------------------------------------------------------
    7820.1: basic grep -i 'how.to'                     0.49(1.72+0.38)
    7820.2: extended grep -i 'how.to'                  0.46(1.64+0.42)
    7820.3: perl grep -i 'how.to'                      0.44(1.45+0.45)
    7820.5: basic grep -i '^how to'                    0.47(1.76+0.38)
    7820.6: extended grep -i '^how to'                 0.47(1.70+0.42)
    7820.7: perl grep -i '^how to'                     0.65(2.72+0.37)
    7820.9: basic grep -i '[how] to'                   0.86(3.64+0.42)
    7820.10: extended grep -i '[how] to'               0.84(3.62+0.46)
    7820.11: perl grep -i '[how] to'                   0.73(3.06+0.39)
    7820.13: basic grep -i '\(e.t[^ ]*\|v.ry\) rare'   1.63(8.13+0.36)
    7820.14: extended grep -i '(e.t[^ ]*|v.ry) rare'   1.64(8.01+0.44)
    7820.15: perl grep -i '(e.t[^ ]*|v.ry) rare'       1.44(6.88+0.44)
    7820.17: basic grep -i 'm\(ú\|u\)lt.b\(æ\|y\)te'   0.66(2.67+0.44)
    7820.18: extended grep -i 'm(ú|u)lt.b(æ|y)te'      0.66(2.67+0.43)
    7820.19: perl grep -i 'm(ú|u)lt.b(æ|y)te'          0.59(2.31+0.37)

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-26 12:52:36 +09:00

57 lines
1.1 KiB
Bash
Executable File

#!/bin/sh
test_description="Comparison of git-grep's regex engines
Set GIT_PERF_7820_GREP_OPTS in the environment to pass options to
git-grep. Make sure to include a leading space,
e.g. GIT_PERF_7820_GREP_OPTS=' -i'. Some options to try:
-i
-w
-v
-vi
-vw
-viw
"
. ./perf-lib.sh
test_perf_large_repo
test_checkout_worktree
for pattern in \
'how.to' \
'^how to' \
'[how] to' \
'\(e.t[^ ]*\|v.ry\) rare' \
'm\(ú\|u\)lt.b\(æ\|y\)te'
do
for engine in basic extended perl
do
if test $engine != "basic"
then
# Poor man's basic -> extended converter.
pattern=$(echo "$pattern" | sed 's/\\//g')
fi
if test $engine = "perl" && ! test_have_prereq PCRE
then
prereq="PCRE"
else
prereq=""
fi
test_perf $prereq "$engine grep$GIT_PERF_7820_GREP_OPTS '$pattern'" "
git -c grep.patternType=$engine grep$GIT_PERF_7820_GREP_OPTS -- '$pattern' >'out.$engine' || :
"
done
test_expect_success "assert that all engines found the same for$GIT_PERF_7820_GREP_OPTS '$pattern'" '
test_cmp out.basic out.extended &&
if test_have_prereq PCRE
then
test_cmp out.basic out.perl
fi
'
done
test_done