From: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
To: 'GNU C Library' <libc-alpha@sourceware.org>
Subject: [PATCH 2/2] Add single-threaded fast path to rand()
Date: Mon, 18 Mar 2024 15:20:33 +0000 [thread overview]
Message-ID: <PAWPR08MB898203ABD80D81B91E5398B4832D2@PAWPR08MB8982.eurprd08.prod.outlook.com> (raw)
Improve performance of rand() and __random() by adding a single-threaded fast
path. Bench-random-lock shows about 5x speedup on Neoverse V1.
OK for commit?
---
diff --git a/stdlib/random.c b/stdlib/random.c
index 62f22fac8d58c7977f09c134bf80a797750da645..174603a8915fd8aa4b3ae64d023003c9e2c038f2 100644
--- a/stdlib/random.c
+++ b/stdlib/random.c
@@ -51,6 +51,7 @@
SUCH DAMAGE.*/
#include <libc-lock.h>
+#include <sys/single_threaded.h>
#include <limits.h>
#include <stddef.h>
#include <stdlib.h>
@@ -288,6 +289,12 @@ __random (void)
{
int32_t retval;
+ if (SINGLE_THREAD_P)
+ {
+ (void) __random_r (&unsafe_state, &retval);
+ return retval;
+ }
+
__libc_lock_lock (lock);
(void) __random_r (&unsafe_state, &retval);
next reply other threads:[~2024-03-18 15:21 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-18 15:20 Wilco Dijkstra [this message]
2024-03-18 19:24 ` [PATCH 2/2] Add single-threaded fast path to rand() Cristian Rodríguez
2024-03-19 15:44 ` Wilco Dijkstra
2024-03-20 12:31 ` Adhemerval Zanella Netto
2024-03-20 14:18 ` Cristian Rodríguez
2024-03-20 14:27 ` Adhemerval Zanella Netto
2024-03-21 7:39 ` Florian Weimer
2024-03-21 13:33 ` Cristian Rodríguez
2024-03-21 14:35 ` Mathieu Desnoyers
2024-03-21 15:07 ` Szabolcs Nagy
2024-03-21 15:18 ` Wilco Dijkstra
2024-03-21 15:53 ` Adhemerval Zanella Netto
2024-03-22 14:27 ` Zack Weinberg
2024-03-22 14:46 ` Adhemerval Zanella Netto
2024-03-22 15:30 ` Zack Weinberg
2024-03-22 18:05 ` Adhemerval Zanella Netto
2024-03-22 19:47 ` Mathieu Desnoyers
2024-03-22 22:54 ` Cristian Rodríguez
2024-03-23 14:01 ` Zack Weinberg
2024-03-23 15:23 ` Mathieu Desnoyers
2024-03-25 14:09 ` Mathieu Desnoyers
2024-03-25 17:52 ` Adhemerval Zanella Netto
2024-03-24 0:59 ` Cristian Rodríguez
2024-03-25 6:44 ` Florian Weimer
2024-03-20 14:28 ` Wilco Dijkstra
2024-03-20 14:40 ` Xi Ruoyao
-- strict thread matches above, loose matches on Subject: below --
2023-11-28 17:37 Wilco Dijkstra
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