From: "Ted Unangst" <tedu@tedunangst.com>
Subject: Re: sys/sysctl: make hw.setperf MP safe
To: "Kirill A. Korinsky" <kirill@korins.ky>
Cc: "OpenBSD tech" <tech@openbsd.org>, mvs@openbsd.org
Date: Wed, 21 May 2025 13:58:13 -0400

On 2025-05-21, Kirill A. Korinsky wrote:
> tech@,
> 
> Here a diff which makes hw.setperf MP safe.

Am I out of the loop? What machine doesn't load an int atomically?

> -		perflevel = 100;
> -		cpu_setperf(perflevel);

> +		atomic_store_int(&perflevel, 100);
> +		cpu_setperf(atomic_load_int(&perflevel));

Constructs like this in particular look weird. If there's a race, 
this doesn't fix it.