diff mbox series

glibc: Add single-threaded fast path to rand()

Message ID 20250331090517.2284874-1-haixiao.yan.cn@eng.windriver.com
State Accepted, archived
Commit b0ded4df5f2d3bb3319978d1a549c72f5daf238e
Headers show
Series glibc: Add single-threaded fast path to rand() | expand

Commit Message

haixiao.yan.cn@eng.windriver.com March 31, 2025, 9:05 a.m. UTC 
From: Haixiao Yan <haixiao.yan.cn@windriver.com>

Backport a patch [1] to improve performance of rand() and __random()[2]
by adding a single-threaded fast path.

[1] https://sourceware.org/git/?p=glibc.git;a=commit;h=be0cfd848d9ad7378800d6302bc11467cf2b514f
[2] https://sourceware.org/bugzilla/show_bug.cgi?id=32777
Signed-off-by: Haixiao Yan <haixiao.yan.cn@windriver.com>
---
 ...dd-single-threaded-fast-path-to-rand.patch | 47 +++++++++++++++++++
 meta/recipes-core/glibc/glibc_2.41.bb         |  1 +
 2 files changed, 48 insertions(+)
 create mode 100644 meta/recipes-core/glibc/glibc/0001-stdlib-Add-single-threaded-fast-path-to-rand.patch

Comments

Khem Raj March 31, 2025, 4:10 p.m. UTC | #1 
Looks ok

On Mon, Mar 31, 2025 at 2:05 AM Yan, Haixiao (CN) via lists.openembedded.org
<Haixiao.Yan.CN=windriver.com@lists.openembedded.org> wrote:

> From: Haixiao Yan <haixiao.yan.cn@windriver.com>
>
> Backport a patch [1] to improve performance of rand() and __random()[2]
> by adding a single-threaded fast path.
>
> [1]
> https://sourceware.org/git/?p=glibc.git;a=commit;h=be0cfd848d9ad7378800d6302bc11467cf2b514f
> [2] https://sourceware.org/bugzilla/show_bug.cgi?id=32777
> Signed-off-by: Haixiao Yan <haixiao.yan.cn@windriver.com>
> ---
>  ...dd-single-threaded-fast-path-to-rand.patch | 47 +++++++++++++++++++
>  meta/recipes-core/glibc/glibc_2.41.bb         |  1 +
>  2 files changed, 48 insertions(+)
>  create mode 100644
> meta/recipes-core/glibc/glibc/0001-stdlib-Add-single-threaded-fast-path-to-rand.patch
>
> diff --git
> a/meta/recipes-core/glibc/glibc/0001-stdlib-Add-single-threaded-fast-path-to-rand.patch
> b/meta/recipes-core/glibc/glibc/0001-stdlib-Add-single-threaded-fast-path-to-rand.patch
> new file mode 100644
> index 000000000000..736fc51f3874
> --- /dev/null
> +++
> b/meta/recipes-core/glibc/glibc/0001-stdlib-Add-single-threaded-fast-path-to-rand.patch
> @@ -0,0 +1,47 @@
> +From 4f54b0dfc16dbe0df86afccb90e447df5f7f571e Mon Sep 17 00:00:00 2001
> +From: Wilco Dijkstra <wilco.dijkstra@arm.com>
> +Date: Mon, 18 Mar 2024 15:18:20 +0000
> +Subject: [PATCH] stdlib: Add single-threaded fast path to rand()
> +MIME-Version: 1.0
> +Content-Type: text/plain; charset=UTF-8
> +Content-Transfer-Encoding: 8bit
> +
> +Improve performance of rand() and __random() by adding a single-threaded
> +fast path.  Bench-random-lock shows about 5x speedup on Neoverse V1.
> +
> +Upstream-Status: Backport [be0cfd848d9ad7378800d6302bc11467cf2b514f]
> +
> +Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
> +Signed-off-by: Haixiao Yan <haixiao.yan.cn@windriver.com>
> +---
> + stdlib/random.c | 7 +++++++
> + 1 file changed, 7 insertions(+)
> +
> +diff --git a/stdlib/random.c b/stdlib/random.c
> +index 17cc61ba8f55..5d482a857065 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);
> +--
> +2.34.1
> +
> diff --git a/meta/recipes-core/glibc/glibc_2.41.bb
> b/meta/recipes-core/glibc/glibc_2.41.bb
> index 71b89ac9ffb3..d707e1a6775d 100644
> --- a/meta/recipes-core/glibc/glibc_2.41.bb
> +++ b/meta/recipes-core/glibc/glibc_2.41.bb
> @@ -53,6 +53,7 @@ SRC_URI =
> "${GLIBC_GIT_URI};branch=${SRCBRANCH};name=glibc \
>
> file://0021-fix-create-thread-failed-in-unprivileged-process-BZ-.patch \
>
> file://0022-Avoid-hardcoded-build-time-paths-in-the-output-binar.patch \
>
> file://0023-tests-Skip-2-qemu-tests-that-can-hang-in-oe-selftest.patch \
> +           file://0001-stdlib-Add-single-threaded-fast-path-to-rand.patch
> \
>  "
>  S = "${WORKDIR}/git"
>  B = "${WORKDIR}/build-${TARGET_SYS}"
> --
> 2.34.1
>
>
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diff mbox series

Patch

diff --git a/meta/recipes-core/glibc/glibc/0001-stdlib-Add-single-threaded-fast-path-to-rand.patch b/meta/recipes-core/glibc/glibc/0001-stdlib-Add-single-threaded-fast-path-to-rand.patch
new file mode 100644
index 000000000000..736fc51f3874
--- /dev/null
+++ b/meta/recipes-core/glibc/glibc/0001-stdlib-Add-single-threaded-fast-path-to-rand.patch
@@ -0,0 +1,47 @@ 
+From 4f54b0dfc16dbe0df86afccb90e447df5f7f571e Mon Sep 17 00:00:00 2001
+From: Wilco Dijkstra <wilco.dijkstra@arm.com>
+Date: Mon, 18 Mar 2024 15:18:20 +0000
+Subject: [PATCH] stdlib: Add single-threaded fast path to rand()
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Improve performance of rand() and __random() by adding a single-threaded
+fast path.  Bench-random-lock shows about 5x speedup on Neoverse V1.
+
+Upstream-Status: Backport [be0cfd848d9ad7378800d6302bc11467cf2b514f]
+
+Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
+Signed-off-by: Haixiao Yan <haixiao.yan.cn@windriver.com>
+---
+ stdlib/random.c | 7 +++++++
+ 1 file changed, 7 insertions(+)
+
+diff --git a/stdlib/random.c b/stdlib/random.c
+index 17cc61ba8f55..5d482a857065 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);
+-- 
+2.34.1
+
diff --git a/meta/recipes-core/glibc/glibc_2.41.bb b/meta/recipes-core/glibc/glibc_2.41.bb
index 71b89ac9ffb3..d707e1a6775d 100644
--- a/meta/recipes-core/glibc/glibc_2.41.bb
+++ b/meta/recipes-core/glibc/glibc_2.41.bb
@@ -53,6 +53,7 @@  SRC_URI =  "${GLIBC_GIT_URI};branch=${SRCBRANCH};name=glibc \
            file://0021-fix-create-thread-failed-in-unprivileged-process-BZ-.patch \
            file://0022-Avoid-hardcoded-build-time-paths-in-the-output-binar.patch \
            file://0023-tests-Skip-2-qemu-tests-that-can-hang-in-oe-selftest.patch \
+           file://0001-stdlib-Add-single-threaded-fast-path-to-rand.patch \
 "
 S = "${WORKDIR}/git"
 B = "${WORKDIR}/build-${TARGET_SYS}"