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authorÆvar Arnfjörð Bjarmason <avarab@gmail.com>2017-05-25 20:05:25 +0000
committerJunio C Hamano <gitster@pobox.com>2017-05-26 12:59:05 +0900
commitfbaceaac4731655540e48845eb3a3e2ce2282b38 (patch)
treec5b0d65c19a4ac2a2d1ecba0f2af1c2bc4c0071e /grep.h
parent7531a2dd876994479484968d361e18b70b2c764e (diff)
downloadgit-fbaceaac4731655540e48845eb3a3e2ce2282b38.tar.gz
grep: add support for the PCRE v1 JIT API
Change the grep PCRE v1 code to use JIT when available. When PCRE support was initially added in commit 63e7e9d8b6 ("git-grep: Learn PCRE", 2011-05-09) PCRE had no JIT support, it was integrated into 8.20 released on 2011-10-21. Enabling JIT support usually improves performance by more than 40%. The pattern compilation times are relatively slower, but those relative numbers are tiny, and are easily made back in all but the most trivial cases of grep. Detailed benchmarks & overview of compilation times is at: http://sljit.sourceforge.net/pcre.html With this change the difference in a t/perf/p7820-grep-engines.sh run is, with just the /perl/ tests shown: $ GIT_PERF_REPEAT_COUNT=30 GIT_PERF_LARGE_REPO=~/g/linux GIT_PERF_MAKE_OPTS='-j8 USE_LIBPCRE=YesPlease CC=~/perl5/installed/bin/gcc NO_R_TO_GCC_LINKER=YesPlease CFLAGS=-O3 LIBPCREDIR=/home/avar/g/pcre/inst LDFLAGS=-Wl,-rpath,/home/avar/g/pcre/inst/lib' ./run HEAD~ HEAD p7820-grep-engines.sh Test HEAD~ HEAD --------------------------------------------------------------------------------------- 7820.3: perl grep 'how.to' 0.35(1.11+0.43) 0.23(0.42+0.46) -34.3% 7820.7: perl grep '^how to' 0.64(2.71+0.36) 0.27(0.66+0.44) -57.8% 7820.11: perl grep '[how] to' 0.63(2.51+0.42) 0.33(0.98+0.39) -47.6% 7820.15: perl grep '(e.t[^ ]*|v.ry) rare' 1.17(5.61+0.35) 0.34(1.08+0.46) -70.9% 7820.19: perl grep 'm(ú|u)lt.b(æ|y)te' 0.43(1.52+0.44) 0.30(0.88+0.42) -30.2% The conditional support for JIT is implemented as suggested in the pcrejit(3) man page. E.g. defining PCRE_STUDY_JIT_COMPILE to 0 if it's not present. The implementation is relatively verbose because even if PCRE_CONFIG_JIT is defined only a call to pcre_config() can determine if the JIT is available, and if so the faster pcre_jit_exec() function should be called instead of pcre_exec(), and a different (but not complimentary!) function needs to be called to free pcre1_extra_info. There's no graceful fallback if pcre_jit_stack_alloc() fails under PCRE_CONFIG_JIT, instead the program will simply abort. I don't think this is worth handling gracefully, it'll only fail in cases where malloc() doesn't work, in which case we're screwed anyway. That there's no assignment of `p->pcre1_jit_on = 0` when PCRE_CONFIG_JIT isn't defined isn't a bug. The create_grep_pat() function allocates the grep_pat allocates it with calloc(), so it's guaranteed to be 0 when PCRE_CONFIG_JIT isn't defined. I you're bisecting and find this change, check that your PCRE isn't older than 8.32. This change intentionally broke really old versions of PCRE, but that's fixed in follow-up commits. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'grep.h')
-rw-r--r--grep.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/grep.h b/grep.h
index 38ac82b638..14f47189f9 100644
--- a/grep.h
+++ b/grep.h
@@ -3,9 +3,13 @@
#include "color.h"
#ifdef USE_LIBPCRE1
#include <pcre.h>
+#ifndef PCRE_STUDY_JIT_COMPILE
+#define PCRE_STUDY_JIT_COMPILE 0
+#endif
#else
typedef int pcre;
typedef int pcre_extra;
+typedef int pcre_jit_stack;
#endif
#include "kwset.h"
#include "thread-utils.h"
@@ -48,7 +52,9 @@ struct grep_pat {
regex_t regexp;
pcre *pcre1_regexp;
pcre_extra *pcre1_extra_info;
+ pcre_jit_stack *pcre1_jit_stack;
const unsigned char *pcre1_tables;
+ int pcre1_jit_on;
kwset_t kws;
unsigned fixed:1;
unsigned ignore_case:1;