@matheusbsbs / matheus-bagliano / commits / b65abcafc7

grep: use PCRE v2 for optimized fixed-string search

Bring back optimized fixed-string search for "grep", this time with PCRE v2 as an optional backend. As noted in [1] with kwset we were slower than PCRE v1 and v2 JIT with the kwset backend, so that optimization was counterproductive. This brings back the optimization for "--fixed-strings", without changing the semantics of having a NUL-byte in patterns. As seen in previous commits in this series we could support it now, but I'd rather just leave that edge-case aside so we don't have one behavior or the other depending what "--fixed-strings" backend we're using. It makes the behavior harder to understand and document, and makes tests for the different backends more painful. This does change the behavior under non-C locales when "log"'s "--encoding" option is used and the heystack/needle in the content/command-line doesn't have a matching encoding. See the recent change in "t4210: skip more command-line encoding tests on MinGW" in this series. I think that's OK. We did nothing sensible before then (just compared raw bytes that had no hope of matching). At least now the user will get some idea why their grep/log never matches in that edge case. I could also support the PCRE v1 backend here, but that would make the code more complex. I'd rather aim for simplicity here and in future changes to the diffcore. We're not going to have someone who absolutely must have faster search, but for whom building PCRE v2 isn't acceptable. The difference between this series of commits and the current "master" is, using the same t/perf commands shown in the last commit: plain grep: Test origin/master HEAD ------------------------------------------------------------------------- 7821.1: fixed grep int 0.55(1.67+0.56) 0.41(0.98+0.60) -25.5% 7821.2: basic grep int 0.58(1.65+0.52) 0.41(0.96+0.57) -29.3% 7821.3: extended grep int 0.57(1.66+0.49) 0.42(0.93+0.60) -26.3% 7821.4: perl grep int 0.54(1.67+0.50) 0.43(0.88+0.65) -20.4% 7821.6: fixed grep uncommon 0.21(0.52+0.42) 0.16(0.24+0.51) -23.8% 7821.7: basic grep uncommon 0.20(0.49+0.45) 0.17(0.28+0.47) -15.0% 7821.8: extended grep uncommon 0.20(0.54+0.39) 0.16(0.25+0.50) -20.0% 7821.9: perl grep uncommon 0.20(0.58+0.36) 0.16(0.23+0.50) -20.0% 7821.11: fixed grep æ 0.35(1.24+0.43) 0.16(0.23+0.50) -54.3% 7821.12: basic grep æ 0.36(1.29+0.38) 0.16(0.20+0.54) -55.6% 7821.13: extended grep æ 0.35(1.23+0.44) 0.16(0.24+0.50) -54.3% 7821.14: perl grep æ 0.35(1.33+0.34) 0.16(0.28+0.46) -54.3% grep with -i: Test origin/master HEAD ---------------------------------------------------------------------------- 7821.1: fixed grep -i int 0.62(1.81+0.70) 0.47(1.11+0.64) -24.2% 7821.2: basic grep -i int 0.67(1.90+0.53) 0.46(1.07+0.62) -31.3% 7821.3: extended grep -i int 0.62(1.92+0.53) 0.53(1.12+0.58) -14.5% 7821.4: perl grep -i int 0.66(1.85+0.58) 0.45(1.10+0.59) -31.8% 7821.6: fixed grep -i uncommon 0.21(0.54+0.43) 0.17(0.20+0.55) -19.0% 7821.7: basic grep -i uncommon 0.20(0.52+0.45) 0.17(0.29+0.48) -15.0% 7821.8: extended grep -i uncommon 0.21(0.52+0.44) 0.17(0.26+0.50) -19.0% 7821.9: perl grep -i uncommon 0.21(0.53+0.44) 0.17(0.20+0.56) -19.0% 7821.11: fixed grep -i æ 0.26(0.79+0.44) 0.16(0.29+0.46) -38.5% 7821.12: basic grep -i æ 0.26(0.79+0.42) 0.16(0.20+0.54) -38.5% 7821.13: extended grep -i æ 0.26(0.84+0.39) 0.16(0.24+0.50) -38.5% 7821.14: perl grep -i æ 0.16(0.24+0.49) 0.17(0.25+0.51) +6.3% plain log: Test origin/master HEAD -------------------------------------------------------------------------------- 4221.1: fixed log --grep='int' 7.24(6.95+0.28) 7.20(6.95+0.18) -0.6% 4221.2: basic log --grep='int' 7.31(6.97+0.22) 7.20(6.93+0.21) -1.5% 4221.3: extended log --grep='int' 7.37(7.04+0.24) 7.22(6.91+0.25) -2.0% 4221.4: perl log --grep='int' 7.31(7.04+0.21) 7.19(6.89+0.21) -1.6% 4221.6: fixed log --grep='uncommon' 6.93(6.59+0.32) 7.04(6.66+0.37) +1.6% 4221.7: basic log --grep='uncommon' 6.92(6.58+0.29) 7.08(6.75+0.29) +2.3% 4221.8: extended log --grep='uncommon' 6.92(6.55+0.31) 7.00(6.68+0.31) +1.2% 4221.9: perl log --grep='uncommon' 7.03(6.59+0.33) 7.12(6.73+0.34) +1.3% 4221.11: fixed log --grep='æ' 7.41(7.08+0.28) 7.05(6.76+0.29) -4.9% 4221.12: basic log --grep='æ' 7.39(6.99+0.33) 7.00(6.68+0.25) -5.3% 4221.13: extended log --grep='æ' 7.34(7.00+0.25) 7.15(6.81+0.31) -2.6% 4221.14: perl log --grep='æ' 7.43(7.13+0.26) 7.01(6.60+0.36) -5.7% log with -i: Test origin/master HEAD ------------------------------------------------------------------------------------ 4221.1: fixed log -i --grep='int' 7.31(7.07+0.24) 7.23(7.00+0.22) -1.1% 4221.2: basic log -i --grep='int' 7.40(7.08+0.28) 7.19(6.92+0.20) -2.8% 4221.3: extended log -i --grep='int' 7.43(7.13+0.25) 7.27(6.99+0.21) -2.2% 4221.4: perl log -i --grep='int' 7.34(7.10+0.24) 7.10(6.90+0.19) -3.3% 4221.6: fixed log -i --grep='uncommon' 7.07(6.71+0.32) 7.11(6.77+0.28) +0.6% 4221.7: basic log -i --grep='uncommon' 6.99(6.64+0.28) 7.12(6.69+0.38) +1.9% 4221.8: extended log -i --grep='uncommon' 7.11(6.74+0.32) 7.10(6.77+0.27) -0.1% 4221.9: perl log -i --grep='uncommon' 6.98(6.60+0.29) 7.05(6.64+0.34) +1.0% 4221.11: fixed log -i --grep='æ' 7.85(7.45+0.34) 7.03(6.68+0.32) -10.4% 4221.12: basic log -i --grep='æ' 7.87(7.49+0.29) 7.06(6.69+0.31) -10.3% 4221.13: extended log -i --grep='æ' 7.87(7.54+0.31) 7.09(6.69+0.31) -9.9% 4221.14: perl log -i --grep='æ' 7.06(6.77+0.28) 6.91(6.57+0.31) -2.1% So as with e05b027627 ("grep: use PCRE v2 for optimized fixed-string search", 2019-06-26) there's a huge improvement in performance for "grep", but in "log" most of our time is spent elsewhere, so we don't notice it that much. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Ævar Arnfjörð Bjarmason committed Jul 1, 2019 at 23:21 UTC b65abcafc7abd93ed634125bcec98b1460e75d2b

1 file changed +49 -2

grep.c

+49 -2

@@ -356,6 +356,18 @@ static NORETURN void compile_regexp_failed(const struct grep_pat *p,

356 die("%s'%s': %s", where, p->pattern, error);

357 }

358

359 +static int is_fixed(const char *s, size_t len)

360 +{

361 + size_t i;

362 +

363 + for (i = 0; i < len; i++) {

364 + if (is_regex_special(s[i]))

365 + return 0;

366 + }

367 +

368 + return 1;

369 +}

370 +

371 #ifdef USE_LIBPCRE1

372 static void compile_pcre1_regexp(struct grep_pat *p, const struct grep_opt *opt)

373 {

@@ -602,7 +614,6 @@ static int pcre2match(struct grep_pat *p, const char *line, const char *eol,

614 static void free_pcre2_pattern(struct grep_pat *p)

615 {

616 }

605 -#endif /* !USE_LIBPCRE2 */

617

618 static void compile_fixed_regexp(struct grep_pat *p, struct grep_opt *opt)

619 {

@@ -623,11 +634,13 @@ static void compile_fixed_regexp(struct grep_pat *p, struct grep_opt *opt)

634 compile_regexp_failed(p, errbuf);

635 }

636 }

637 +#endif /* !USE_LIBPCRE2 */

638

639 static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)

640 {

641 int err;

642 int regflags = REG_NEWLINE;

643 + int pat_is_fixed;

644

645 p->word_regexp = opt->word_regexp;

646 p->ignore_case = opt->ignore_case;

@@ -636,8 +649,42 @@ static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)

649 if (memchr(p->pattern, 0, p->patternlen) && !opt->pcre2)

650 die(_("given pattern contains NULL byte (via -f <file>). This is only supported with -P under PCRE v2"));

651

639 - if (opt->fixed) {

652 + pat_is_fixed = is_fixed(p->pattern, p->patternlen);

653 + if (opt->fixed || pat_is_fixed) {

654 +#ifdef USE_LIBPCRE2

655 + opt->pcre2 = 1;

656 + if (pat_is_fixed) {

657 + compile_pcre2_pattern(p, opt);

658 + } else {

659 + /*

660 + * E.g. t7811-grep-open.sh relies on the

661 + * pattern being restored.

662 + */

663 + char *old_pattern = p->pattern;

664 + size_t old_patternlen = p->patternlen;

665 + struct strbuf sb = STRBUF_INIT;

666 +

667 + /*

668 + * There is the PCRE2_LITERAL flag, but it's

669 + * only in PCRE v2 10.30 and later. Needing to

670 + * ifdef our way around that and dealing with

671 + * it + PCRE2_MULTILINE being an error is more

672 + * complex than just quoting this ourselves.

673 + */

674 + strbuf_add(&sb, "\\Q", 2);

675 + strbuf_add(&sb, p->pattern, p->patternlen);

676 + strbuf_add(&sb, "\\E", 2);

677 +

678 + p->pattern = sb.buf;

679 + p->patternlen = sb.len;

680 + compile_pcre2_pattern(p, opt);

681 + p->pattern = old_pattern;

682 + p->patternlen = old_patternlen;

683 + strbuf_release(&sb);

684 + }

685 +#else /* !USE_LIBPCRE2 */

686 compile_fixed_regexp(p, opt);

687 +#endif /* !USE_LIBPCRE2 */

688 return;

689 }

690