freebsd stable - May 2011 - [poll] hyperthreading_allowed, hlt_logical_cpus, mp_watchdog

I am planning on some changes in head and would like to see if people use the
following features:
- machdep.hyperthreading_allowed tunable and sysctl
- machdep.hlt_logical_cpus tunable and sysctl
- mp_watchdog kernel option

If you are using any of the above, please let me know - better via a private
reply:
- which exactly of the mentioned above features you use
- please make distinction between use of tunables and sysctls
- tell for what you use the feature
- provide overview of your hardware, which scheduler you use and intended
purpose
of the system

Thank you!
-- 
Andriy Gapon

On 24/05/2011 15:21, Andriy Gapon wrote:
>
> I am planning on some changes in head and would like to see if people use
the
> following features:
> - machdep.hyperthreading_allowed tunable and sysctl
> - machdep.hlt_logical_cpus tunable and sysctl
> - mp_watchdog kernel option
>
> If you are using any of the above, please let me know - better via a
private reply:
> - which exactly of the mentioned above features you use
> - please make distinction between use of tunables and sysctls
> - tell for what you use the feature
> - provide overview of your hardware, which scheduler you use and intended
purpose
> of the system
Whatever you do, please leave at least some way (at least a tunable) to 
enable/disable HTT - some workloads are better with, and some without 
it, and some BIOSes are unreliable in enabling/disabling it :)

Le Tue, 24 May 2011 16:21:08 +0300,
Andriy Gapon <avg@FreeBSD.org> a ?crit :

Hello,
 
> I am planning on some changes in head and would like to see if people
> use the following features:
> - machdep.hyperthreading_allowed tunable and sysctl
If I remember well, these tunables were introduced because the
paper of Colin Percival about the HTT security flaw on intel
processors :
http://www.daemonology.net/hyperthreading-considered-harmful/

http://security.freebsd.org/advisories/FreeBSD-SA-05:09.htt.asc

I guess this is still a concern?.

Best regards.