Re: Raptor Lake / Alder lake on RELENG_13 ?

From: Mike Karels <>
Date: Tue, 07 Feb 2023 13:29:15 UTC
On 6 Feb 2023, at 16:04, mike tancsa wrote:

> Hi All,
>     I have seen a couple of commits around these CPUs, but wondering if anyone is running 13 on these newer hybrid CPUs ? Do the slower cores just get disabled or are they made use of somehow ?
>     ---Mike

I have been testing the changes on -current, and they are working fine.  I have not tested on 13, but I would expect the same result.  The workaround is on 13-stable, but not yet a RELENG branch.  Presumably it will be in 13.2 when it is branched.  If no one else has reported, I will test the 13.2 branch.  Also, I haven’t heard of tests on Raptor Lake, but I have heard that the behavior should be the same as Alder Lake.

The E-cores are not disabled.  They are forced to use a less efficient method of page invalidation.  They are scheduled as if they were P-cores without threads, but they are less used because of the shared cache among 4 cores rather than 2.  I have some preliminary scheduler changes that recognize the slower cores, but there are still issues to be dealt with.