Re: SMP in 5.1 cant deactivate hyperthreading
On Thu, 12 Jun 2003, Killing wrote: > > Halting them will still cause the CPUs to be detected. They just won't do > > any useful work. > > Yep but the issue is that all the core admin tools are unaware of this and > hence include the virtual cores in idle calcs etc making load monitoring > impossible without nasty cludges :( > > So what's the way forward? > 1. Dont just use halt have a compile or other directive to disable them? > 2. Update all tools to be halt aware? > > Personally I'd go with 2 all be it more work / ramifications on other 3rd party > tools as it gives the benefit of also working when physical CPU's are halted. Guh. Checking with some people here, it appears that the HT stuff is still undergoing some tweaking. I'd suggest that you stay tuned for any commits from john baldwin re: HT. Your case appears to be unique. -- Doug White| FreeBSD: The Power to Serve [EMAIL PROTECTED] | www.FreeBSD.org ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: SMP in 5.1 cant deactivate hyperthreading
Original Message - From: "John-Mark Gurney" <[EMAIL PROTECTED]> > > Yes 5.X is still new tech and may not run on all machines but on the ones > > which it does ( and it runs very well here ) basic tools are required. If > > it doesn't run on a machine your under know false impressions, if however > > you users complain of performance issues and you look @ top and it says > > 50% idle and its really 0% idle its a different matter. > > That's a good way to remind the admin to turn the cpu back on. Don't by it there just checking sysctl is easy enough. > Now is there any good reason why you need to keep the cpu disabled? Its disabled by default due to performance reasons and we keep it that way. We are talking hyperthreading, logical CPU's, not real physical CPU's. Its quite easy to see if CPU's are disabled as mentioned above. If you check the release notes for top then you'll see a similar fix had to be made for sunos5 in beta5 iirc. Steve ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: SMP in 5.1 cant deactivate hyperthreading
Killing wrote this message on Thu, Jun 12, 2003 at 18:47 +0100: > I suppose the hurry is that basic utils that we use day to day like top > and vmstat to monitor machine load cannot be trusted to give accurate > info. Actually, the basic tools ARE correct, there is a cpu sitting idle that the sysadmin disabled. So, if the sysadmin would reenable the cpu, then jobs could be dispatached to it. Would you rather some junior admin go and disable the cpu, and then six months later wondering why the performance is so slow? > Yes 5.X is still new tech and may not run on all machines but on the ones > which it does ( and it runs very well here ) basic tools are required. If > it doesn't run on a machine your under know false impressions, if however > you users complain of performance issues and you look @ top and it says > 50% idle and its really 0% idle its a different matter. That's a good way to remind the admin to turn the cpu back on. Now is there any good reason why you need to keep the cpu disabled? -- John-Mark Gurney Voice: +1 415 225 5579 "All that I will do, has been done, All that I have, has not." ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: SMP in 5.1 cant deactivate hyperthreading
> Well, hyperthreading can be disabled via a kernel directive, right? >From what I've seen that was removed between 5.0 and 5.1 correct me if Im wrong. > > Which ever it needs someone to pick it up ASAP dont you think? > > Really? What's the hurry? FreeBSD 5.x isn't even bootable/installable > on a number of SMP machines yet (ex. Dell Poweredge 6350). I suppose the hurry is that basic utils that we use day to day like top and vmstat to monitor machine load cannot be trusted to give accurate info. Yes 5.X is still new tech and may not run on all machines but on the ones which it does ( and it runs very well here ) basic tools are required. If it doesn't run on a machine your under know false impressions, if however you users complain of performance issues and you look @ top and it says 50% idle and its really 0% idle its a different matter. Steve / K ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: SMP in 5.1 cant deactivate hyperthreading
On Thu, 12 Jun 2003, Killing wrote: > - Original Message - > From: "Doug White" <[EMAIL PROTECTED]> > > > sysctl machdep.hlt_logical_cpus: > > > machdep.hlt_logical_cpus: 1 > > > > Halting them will still cause the CPUs to be detected. They just won't do > > any useful work. > > Yep but the issue is that all the core admin tools are unaware of this and > hence include the virtual cores in idle calcs etc making load monitoring > impossible without nasty cludges :( > > So what's the way forward? > 1. Dont just use halt have a compile or other directive to disable them? > 2. Update all tools to be halt aware? > > Personally I'd go with 2 all be it more work / ramifications on other 3rd party > tools as it gives the benefit of also working when physical CPU's are halted. Well, hyperthreading can be disabled via a kernel directive, right? > Which ever it needs someone to pick it up ASAP dont you think? Really? What's the hurry? FreeBSD 5.x isn't even bootable/installable on a number of SMP machines yet (ex. Dell Poweredge 6350). > Steve Tom ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: SMP in 5.1 cant deactivate hyperthreading
- Original Message - From: "Doug White" <[EMAIL PROTECTED]> > > sysctl machdep.hlt_logical_cpus: > > machdep.hlt_logical_cpus: 1 > > Halting them will still cause the CPUs to be detected. They just won't do > any useful work. Yep but the issue is that all the core admin tools are unaware of this and hence include the virtual cores in idle calcs etc making load monitoring impossible without nasty cludges :( So what's the way forward? 1. Dont just use halt have a compile or other directive to disable them? 2. Update all tools to be halt aware? Personally I'd go with 2 all be it more work / ramifications on other 3rd party tools as it gives the benefit of also working when physical CPU's are halted. Which ever it needs someone to pick it up ASAP dont you think? Steve ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: SMP in 5.1 cant deactivate hyperthreading
On Wed, 11 Jun 2003, Steven Hartland wrote: > sysctl machdep.hlt_logical_cpus: > machdep.hlt_logical_cpus: 1 Halting them will still cause the CPUs to be detected. They just won't do any useful work. > Relevant sections from dmesg: > Programming 24 pins in IOAPIC #0 > IOAPIC #0 intpin 2 -> irq 0 > Programming 24 pins in IOAPIC #1 > Programming 24 pins in IOAPIC #2 > FreeBSD/SMP: Multiprocessor System Detected: 4 CPUs > cpu0 (BSP): apic id: 0, version: 0x00050014, at 0xfee0 > cpu1 (AP): apic id: 6, version: 0x00050014, at 0xfee0 > cpu2 (AP): apic id: 1, version: 0x00050014, at 0xfee0 > cpu3 (AP): apic id: 7, version: 0x00050014, at 0xfee0 -- Doug White| FreeBSD: The Power to Serve [EMAIL PROTECTED] | www.FreeBSD.org ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "[EMAIL PROTECTED]"
