[PATCH 3/3] aarch64: Remove non-temporal load/stores from oryon-1's memset

[Adhemerval Zanella]

On Fri, Nov 15, 2024 at 12:05 AM Andrew Pinski <quic_apinski@quicinc.com> wrote:
>
> The hardware architects have a new recommendation not to use
> non-temporal load/stores for memset. This patch removes this path.
> I found there was no difference in the memset speed with/without
> non-temporal load/stores either.
>
> Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>

LGTM, thanks.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>


> ---
>  sysdeps/aarch64/multiarch/memset_oryon1.S | 26 -----------------------
>  1 file changed, 26 deletions(-)
>
> diff --git a/sysdeps/aarch64/multiarch/memset_oryon1.S b/sysdeps/aarch64/multiarch/memset_oryon1.S
> index 6fa28a9bd0..b63c16ec51 100644
> --- a/sysdeps/aarch64/multiarch/memset_oryon1.S
> +++ b/sysdeps/aarch64/multiarch/memset_oryon1.S
> @@ -93,8 +93,6 @@ L(set_long):
>         cmp     count, 256
>         ccmp    valw, 0, 0, cs
>         b.eq    L(try_zva)
> -       cmp     count, #32768
> -       b.hi    L(set_long_with_nontemp)
>         /* Small-size or non-zero memset does not use DC ZVA. */
>         sub     count, dstend, dst
>
> @@ -117,30 +115,6 @@ L(set_long):
>         stp     val, val, [dstend, -16]
>         ret
>
> -L(set_long_with_nontemp):
> -       /* Small-size or non-zero memset does not use DC ZVA. */
> -       sub     count, dstend, dst
> -
> -       /* Adjust count and bias for loop. By subtracting extra 1 from count,
> -          it is easy to use tbz instruction to check whether loop tailing
> -          count is less than 33 bytes, so as to bypass 2 unnecessary stps. */
> -       sub     count, count, 64+16+1
> -
> -1:     stnp    val, val, [dst, 16]
> -       stnp    val, val, [dst, 32]
> -       stnp    val, val, [dst, 48]
> -       stnp    val, val, [dst, 64]
> -       add     dst, dst, #64
> -       subs    count, count, 64
> -       b.hs    1b
> -
> -       tbz     count, 5, 1f    /* Remaining count is less than 33 bytes? */
> -       stnp    val, val, [dst, 16]
> -       stnp    val, val, [dst, 32]
> -1:     stnp    val, val, [dstend, -32]
> -       stnp    val, val, [dstend, -16]
> -       ret
> -
>  L(try_zva):
>         /* Write the first and last 64 byte aligned block using stp rather
>            than using DC ZVA as it is faster. */
> --
> 2.43.0
>