grep: allow threading even on a single-core machine

vleschuk · gitster · commit b6b468b2bfaa · 2015-12-15T10:43:30.000-08:00
Earlier we disabled threading when online_cpus() said "1", but on a
filesystem with long latency (or in a cold cache situation), using
multiple threads to drive I/O in parallel would improve performance
even on a single-core machines.

Signed-off-by: Victor Leschuk &lt;vleschuk@accesssoftek.com&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
diff --git a/builtin/grep.c b/builtin/grep.c
@@ -832,7 +832,7 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 	}
 
 #ifndef NO_PTHREADS
-	if (list.nr || cached || online_cpus() == 1)
+	if (list.nr || cached)
 		use_threads = 0;
 #else
 	use_threads = 0;

Original file line number	Diff line number	Diff line change
`@@ -832,7 +832,7 @@ int cmd_grep(int argc, const char *argv, const char prefix)`
`832`	`832`	`}`
`833`	`833`
`834`	`834`	`#ifndef NO_PTHREADS`
`835`		`- if (list.nr \|\| cached \|\| online_cpus() == 1)`
	`835`	`+ if (list.nr \|\| cached)`
`836`	`836`	`use_threads = 0;`
`837`	`837`	`#else`
`838`	`838`	`use_threads = 0;`