Re: OpenBSD-current (Changelog): Disable Speedstep and p4tcc setperf mechanisms on SMP systems
Brian Curtis wrote: > I was reviewing the changelog for OpenBSD-current and came across the > following: > > "Disable Speedstep and p4tcc setperf mechanisms on SMP systems." This was done because the current setperf implementation isn't smp-safe. Fixing this is a rather large undertaking, however; but if you've got patches, post them to -tech. ;)
Re: OpenBSD-current (Changelog): Disable Speedstep and p4tcc setperf mechanisms on SMP systems
On Tue, 2006-08-22 at 10:23 -0400, Brian Curtis wrote: > Not knowing exactly what Speedstep was, I did some research and discovered > it was an Intel technology for dynamic adjustment of processor speed. This > seems like an excellent feature for systems requiring low power consumption > (laptops, large scale server farms--Google, etc.). What I don't understand > is why it would be disabled for SMP. Is this specific to OpenBSD? Is this > something a developer should look into fixing (i.e. I'm a developer, I might > want to fix it for the experience)? In my experience, dynamic frequency scaling has been somewhat unstable on SMP systems, including other OS that have had SMP longer (like Linux), not just OpenBSD. Specifically, my experience deals with frequency scaling on SMP systems under heavy load tend to lock up. Not sure if this is the reason that the devs disabled it, but it wouldn't suprise me if it were. later. ryanc -- Ryan Corder <[EMAIL PROTECTED]> Systems Engineer, NovaSys Health LLC. 501-219- ext. 646 [demime 1.01d removed an attachment of type application/pgp-signature which had a name of signature.asc]
OpenBSD-current (Changelog): Disable Speedstep and p4tcc setperf mechanisms on SMP systems
Forgive me if I should have posted this question to the SMP mailing list. I was reviewing the changelog for OpenBSD-current and came across the following: "Disable Speedstep and p4tcc setperf mechanisms on SMP systems." Not knowing exactly what Speedstep was, I did some research and discovered it was an Intel technology for dynamic adjustment of processor speed. This seems like an excellent feature for systems requiring low power consumption (laptops, large scale server farms--Google, etc.). What I don't understand is why it would be disabled for SMP. Is this specific to OpenBSD? Is this something a developer should look into fixing (i.e. I'm a developer, I might want to fix it for the experience)? Brian
