[PATCH] x86: Increase allowable TSX abort rate to 6%.

[H.J. Lu]

On Thu, Nov 13, 2025 at 11:01 PM Carlos O'Donell <carlos@redhat.com> wrote:
>
> In pre-commit CI on an E5-2698 v4 we sometimes see ~5% aborts.
>
> Set the trip point to 6%.
> ---
>  sysdeps/x86/tst-string-rtm.h | 20 +++++++++++++++++---
>  1 file changed, 17 insertions(+), 3 deletions(-)
>
> diff --git a/sysdeps/x86/tst-string-rtm.h b/sysdeps/x86/tst-string-rtm.h
> index 1bf863063f..699c52227b 100644
> --- a/sysdeps/x86/tst-string-rtm.h
> +++ b/sysdeps/x86/tst-string-rtm.h
> @@ -36,6 +36,18 @@ do_test_1 (const char *name, unsigned int loop, int (*prepare) (void),
>    unsigned int i;
>    unsigned int naborts = 0;
>    unsigned int failed = 0;
> +
> +  /* Iterate LOOP number of times, calling the same function over
> +     and over again in an attempt to detect the following failure
> +     modes:
> +
> +     1. Aborting instruction on the hot path.
> +     2. Number of instructions executed exceeds maximum.
> +     3. Memory reads or writes exceed maximum.
> +
> +     The function getting bigger may increase the abort rate due
> +     to external events, despite not triggering #2 above, and may
> +     need adjusting the abort rate failure test below.  */
>    for (i = 0; i < loop; i++)
>      {
>        failed |= function ();
> @@ -56,10 +68,12 @@ do_test_1 (const char *name, unsigned int loop, int (*prepare) (void),
>
>    if (naborts)
>      {
> -      /* NB: Low single digit (<= 5%) noise-level aborts are normal for
> -        TSX.  */
> +      /* Low single digit (<= 5%) noise-level aborts are normal for TSX
> +        for reasons that are outside of the library's control.
> +        In pre-commit CI on an E5-2698 v4 we sometimes see ~5% aborts.
> +        Set the trip point to 6%.  */
>        double rate = 100 * ((double) naborts) / ((double) loop);
> -      if (rate > 5)
> +      if (rate > 6)
>         FAIL_EXIT1 ("TSX abort rate: %.2f%% (%d out of %d)",
>                     rate, naborts, loop);
>      }
> --
> 2.51.1
>

LGTM.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>

Thanks.

-- 
H.J.