From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: git@vger.kernel.org
Cc: "Junio C Hamano" <gitster@pobox.com>, "Jeff King" <peff@peff.net>,
"Jeffrey Walton" <noloader@gmail.com>,
"Michał Kiedrowicz" <michal.kiedrowicz@gmail.com>,
"J Smith" <dark.panda@gmail.com>,
"Victor Leschuk" <vleschuk@gmail.com>,
"Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>,
"Fredrik Kuivinen" <frekui@gmail.com>,
"Brandon Williams" <bmwill@google.com>,
"Stefan Beller" <sbeller@google.com>,
"Johannes Schindelin" <johannes.schindelin@gmx.de>,
"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Subject: [PATCH v4 2/8] grep: skip pthreads overhead when using one thread
Date: Thu, 1 Jun 2017 18:20:50 +0000 [thread overview]
Message-ID: <20170601182056.31142-3-avarab@gmail.com> (raw)
In-Reply-To: <20170601182056.31142-1-avarab@gmail.com>
Skip the administrative overhead of using pthreads when only using one
thread. Instead take the non-threaded path which would be taken under
NO_PTHREADS.
The threading support was initially added in commit
5b594f457a ("Threaded grep", 2010-01-25) with a hardcoded compile-time
number of 8 threads. Later the number of threads was made configurable
in commit 89f09dd34e ("grep: add --threads=<num> option and
grep.threads configuration", 2015-12-15).
That change did not add any special handling for --threads=1. Now we
take a slightly faster path by skipping thread handling entirely when
1 thread is requested.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
builtin/grep.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/builtin/grep.c b/builtin/grep.c
index 6e1744550c..a0a3922f92 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -1238,6 +1238,8 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
num_threads = GREP_NUM_THREADS_DEFAULT;
else if (num_threads < 0)
die(_("invalid number of threads specified (%d)"), num_threads);
+ if (num_threads == 1)
+ num_threads = 0;
#else
if (num_threads)
warning(_("no threads support, ignoring --threads"));
--
2.13.0.303.g4ebf302169
next prev parent reply other threads:[~2017-06-01 18:21 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-01 18:20 [PATCH v4 0/8] PCRE v2, PCRE v1 JIT, log -P & fixes Ævar Arnfjörð Bjarmason
2017-06-01 18:20 ` [PATCH v4 1/8] grep: don't redundantly compile throwaway patterns under threading Ævar Arnfjörð Bjarmason
2017-06-01 18:20 ` Ævar Arnfjörð Bjarmason [this message]
2017-06-01 21:20 ` [PATCH v4 2/8] grep: skip pthreads overhead when using one thread Stefan Beller
2017-06-01 21:36 ` Ævar Arnfjörð Bjarmason
2017-06-01 21:38 ` Ævar Arnfjörð Bjarmason
2017-06-01 21:45 ` Stefan Beller
2017-06-01 21:55 ` Ævar Arnfjörð Bjarmason
2017-06-01 22:08 ` Stefan Beller
2017-06-01 18:20 ` [PATCH v4 3/8] log: add -P as a synonym for --perl-regexp Ævar Arnfjörð Bjarmason
2017-06-01 18:20 ` [PATCH v4 4/8] grep: add support for the PCRE v1 JIT API Ævar Arnfjörð Bjarmason
2017-06-01 18:20 ` [PATCH v4 5/8] grep: un-break building with PCRE < 8.32 Ævar Arnfjörð Bjarmason
2017-06-01 18:20 ` [PATCH v4 6/8] grep: un-break building with PCRE < 8.20 Ævar Arnfjörð Bjarmason
2017-06-01 18:20 ` [PATCH v4 7/8] grep: un-break building with PCRE >= 8.32 without --enable-jit Ævar Arnfjörð Bjarmason
2017-06-01 18:20 ` [PATCH v4 8/8] grep: add support for PCRE v2 Ævar Arnfjörð Bjarmason
2017-06-01 23:30 ` [PATCH v4 0/8] PCRE v2, PCRE v1 JIT, log -P & fixes Junio C Hamano
2017-06-02 16:10 ` Johannes Schindelin
2017-06-02 16:45 ` Ævar Arnfjörð Bjarmason
2017-06-05 0:38 ` Junio C Hamano
2017-06-07 15:50 ` Johannes Schindelin
2017-06-07 16:14 ` Ævar Arnfjörð Bjarmason
2017-06-09 13:09 ` Junio C Hamano
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