Re: [PATCH] thread-utils.c: detect online CPU count on OpenBSD / NetBSD

From: Brad Smith <brad@comstyle.com>
Date: May 31, 2025, 20:18 UTC
Message-ID: <f929a4b5-1011-42dd-ad86-bb654d170db2@comstyle.com>
In-Reply-To: <aB2c-W0V83aVDpZr@humpty.home.comstyle.com>

ping.

On 2025-05-09 2:13 a.m., Brad Smith wrote:

Show 30 quoted lines

> OpenBSD / NetBSD use HW_NCPUONLINE to detect the online CPU
> count. OpenBSD ships with SMT disabled on X86 systems so
> HW_NCPU would provide double the number of CPUs as opposed
> to the proper online count.
>
> Signed-off-by: Brad Smith <brad@comstyle.com>
> ---
>   thread-utils.c | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/thread-utils.c b/thread-utils.c
> index 1f89ffab4c..374890e6b0 100644
> --- a/thread-utils.c
> +++ b/thread-utils.c
> @@ -46,11 +46,11 @@ int online_cpus(void)
>   	mib[0] = CTL_HW;
>   #  ifdef HW_AVAILCPU
>   	mib[1] = HW_AVAILCPU;
> -	len = sizeof(cpucount);
> -	if (!sysctl(mib, 2, &cpucount, &len, NULL, 0))
> -		return cpucount;
> -#  endif /* HW_AVAILCPU */
> +#  elif defined(HW_NCPUONLINE)
> +	mib[1] = HW_NCPUONLINE;
> +#  else
>   	mib[1] = HW_NCPU;
> +#  endif /* HW_AVAILCPU */
>   	len = sizeof(cpucount);
>   	if (!sysctl(mib, 2, &cpucount, &len, NULL, 0))
>   		return cpucount;