lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Thu, 26 Nov 2020 11:11:28 +1100
From:   Balbir Singh <>
To:     Peter Zijlstra <>
Cc:     "Joel Fernandes (Google)" <>,
        Nishanth Aravamudan <>,
        Julien Desfossez <>,
        Tim Chen <>,
        Vineeth Pillai <>,
        Aaron Lu <>,
        Aubrey Li <>,,,,,,,,
        Phil Auld <>,
        Valentin Schneider <>,
        Mel Gorman <>,
        Pawan Gupta <>,
        Paolo Bonzini <>,,
        Chen Yu <>,
        Christian Brauner <>,
        Agata Gruza <>,
        Antonio Gomez Iglesias <>,,,,,,,,
        Alexandre Chartre <>,,,
        Dhaval Giani <>,
        Junaid Shahid <>,,, Ben Segall <>,
        Josh Don <>, Hao Luo <>,
        Tom Lendacky <>,
        Aubrey Li <>,
        "Paul E. McKenney" <>,
        Tim Chen <>
Subject: Re: [PATCH -tip 31/32] sched: Add a coresched command line option

On Wed, Nov 25, 2020 at 02:45:37PM +0100, Peter Zijlstra wrote:
> On Tue, Nov 17, 2020 at 06:20:01PM -0500, Joel Fernandes (Google) wrote:
> > Some hardware such as certain AMD variants don't have cross-HT MDS/L1TF
> > issues. Detect this and don't enable core scheduling as it can
> > needlessly slow those device down.
> > 
> > However, some users may want core scheduling even if the hardware is
> > secure. To support them, add a coresched= option which defaults to
> > 'secure' and can be overridden to 'on' if the user wants to enable
> > coresched even if the HW is not vulnerable. 'off' would disable
> > core scheduling in any case.
> This is all sorts of wrong, and the reason is because you hard-coded
> that stupid policy.
> Core scheduling should always be available on SMT (provided you did that
> CONFIG_ thing). Even on AMD systems RT tasks might want to claim the
> core exclusively.

Agreed, specifically if we need to have special cgroup tag/association to
enable it.

Balbir Singh.

Powered by blists - more mailing lists