From: "H.J. Lu" <hjl.tools@gmail.com>
To: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Cc: libc-alpha@sourceware.org,
Noah Goldstein <goldstein.w.n@gmail.com>,
Sajan Karumanchi <sajan.karumanchi@gmail.com>,
bmerry@sarao.ac.za, pmallapp@amd.com
Subject: Re: [PATCH v3 3/3] x86: Expand the comment on when REP STOSB is used on memset
Date: Mon, 12 Feb 2024 07:56:46 -0800 [thread overview]
Message-ID: <CAMe9rOoJY2NCpLY7WB-pwTdw7v_vKjCjckUkm78vutBy74WHNA@mail.gmail.com> (raw)
In-Reply-To: <20240208130840.533348-4-adhemerval.zanella@linaro.org>
On Thu, Feb 8, 2024 at 5:08 AM Adhemerval Zanella
<adhemerval.zanella@linaro.org> wrote:
>
> ---
> sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
> index 9984c3ca0f..97839a2248 100644
> --- a/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
> +++ b/sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S
> @@ -21,7 +21,9 @@
> 2. If size is less than VEC, use integer register stores.
> 3. If size is from VEC_SIZE to 2 * VEC_SIZE, use 2 VEC stores.
> 4. If size is from 2 * VEC_SIZE to 4 * VEC_SIZE, use 4 VEC stores.
> - 5. If size is more to 4 * VEC_SIZE, align to 4 * VEC_SIZE with
> + 5. On machines ERMS feature, if size is greater or equal than
> + __x86_rep_stosb_threshold then REP STOSB will be used.
> + 6. If size is more to 4 * VEC_SIZE, align to 4 * VEC_SIZE with
> 4 VEC stores and store 4 * VEC at a time until done. */
>
> #include <sysdep.h>
> --
> 2.34.1
>
LGTM.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
Thanks.
--
H.J.
next prev parent reply other threads:[~2024-02-12 15:57 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-08 13:08 [PATCH v3 0/3] x86: Improve ERMS usage on Zen3+ Adhemerval Zanella
2024-02-08 13:08 ` [PATCH v3 1/3] x86: Fix Zen3/Zen4 ERMS selection (BZ 30994) Adhemerval Zanella
2024-02-12 15:56 ` H.J. Lu
2024-02-08 13:08 ` [PATCH v3 2/3] x86: Do not prefer ERMS for memset on Zen3+ Adhemerval Zanella
2024-02-12 15:56 ` H.J. Lu
2024-02-08 13:08 ` [PATCH v3 3/3] x86: Expand the comment on when REP STOSB is used on memset Adhemerval Zanella
2024-02-12 15:56 ` H.J. Lu [this message]
2024-03-25 15:15 ` [PATCH v3 0/3] x86: Improve ERMS usage on Zen3+ Florian Weimer
2024-03-25 15:19 ` H.J. Lu
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