Re: [PATCH] fix threaded grep for machines with only one cpu
From: Junio C Hamano <hidden>
Date: 2016-06-15 22:48:17
Subsystem:
the rest · Maintainer:
Linus Torvalds
Possibly related (same subject, not in this thread)
- 2016-06-15 · Re: [PATCH] fix threaded grep for machines with only one cpu · Paolo Bonzini <hidden>
- 2016-06-15 · Re: Re: [PATCH] fix threaded grep for machines with only one cpu · Heiko Voigt <hidden>
- 2016-06-15 · Re: Re: [PATCH] fix threaded grep for machines with only one cpu · Heiko Voigt <hidden>
- 2016-06-15 · Re: Re: [PATCH] fix threaded grep for machines with only one cpu · Johannes Schindelin <hidden>
- 2016-06-15 · [PATCH] fix threaded grep for machines with only one cpu · Heiko Voigt <hidden>
Junio C Hamano [off-list ref] writes:
So at least for grep_mutex your patch shouldn't matter. Please explain use of which mutex is broken and how your patch fixes it.
Is this the answer to my question? With your patch, your single-threaded program will end up locking and unlocking this mutex needlessly, and the mutex is left undestroyed after you are done, I think. builtin-grep.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/builtin-grep.c b/builtin-grep.c
index 26d4deb..5c1545e 100644
--- a/builtin-grep.c
+++ b/builtin-grep.c@@ -81,8 +81,8 @@ static pthread_mutex_t read_sha1_mutex; #define grep_lock() pthread_mutex_lock(&grep_mutex) #define grep_unlock() pthread_mutex_unlock(&grep_mutex) -#define read_sha1_lock() pthread_mutex_lock(&read_sha1_mutex) -#define read_sha1_unlock() pthread_mutex_unlock(&read_sha1_mutex) +#define read_sha1_lock() do { if (use_threads) pthread_mutex_lock(&read_sha1_mutex); } while (0) +#define read_sha1_unlock() do { if (use_threads) pthread_mutex_unlock(&read_sha1_mutex); } while (0) /* Signalled when a new work_item is added to todo. */ static pthread_cond_t cond_add;