Re: Hyperthreading in 6.x ... still frowned upon?
On Wed, 3 May 2006, Chuck Swiger wrote: Is it still something that I should disable, and, if so, how in 6.x? You should test it for the workloads you have, but most of the time, HT isn't especially helpful. AMD64 CPUs come in dual-core format rather than HT-enabled. If you've seen HT or HTT applied to an AMD system, it's likely an abbreviation for HyperTransport or HyperTransport Technology. The workloads I've seen the best improvement in performance for HTT have been ones involving a healthy blend of floating point and integer instruction mixes, or ones with a lot of memory stalls. Something worth remembering is that HTT hardware has, in fact, improved since earlier CPUs, and I've seen HTT go from a net loss in some critical workloads to breakeven or win. My recommendation would be to evaluate the performance impact of HTT against your specific workload and see what impact it has, but not be surprised if it doesn't help. Robert N M Watson ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Hyperthreading in 6.x ... still frowned upon?
Marc G. Fournier wrote: In 4.x, it was a 'shut it off' sort of deal .. my new amd64 don't appear to have it enabled, but my older i386 server that I just upgraded to 6.x does: user pid %cpu %mem vsz rss tt state starttime command root 14 104.0 0.0 0 8 ?? RL11:38AM 0:55.02 [idle: cpu0] root 11 99.1 0.0 0 8 ?? RL11:38AM 0:00.00 [idle: cpu3] root 13 99.1 0.0 0 8 ?? RL11:38AM 0:00.00 [idle: cpu1] root 12 98.0 0.0 0 8 ?? RL11:38AM 0:54.54 [idle: cpu2] Is it still something that I should disable, and, if so, how in 6.x? According to the 6.0 i386 Release Notes, you should use the machdep.hyperthreading_allowed sysctl to disable Hyper-Threading. If you are concerned with security, you should disable it. If you are more concerned with performance, you should test your workload with/without Hyper-Threading and choose the configuration which performs best. -Jonathan ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
Hyperthreading in 6.x ... still frowned upon?
In 4.x, it was a 'shut it off' sort of deal .. my new amd64 don't appear to have it enabled, but my older i386 server that I just upgraded to 6.x does: user pid %cpu %mem vsz rss tt state starttime command root 14 104.0 0.0 0 8 ?? RL11:38AM 0:55.02 [idle: cpu0] root 11 99.1 0.0 0 8 ?? RL11:38AM 0:00.00 [idle: cpu3] root 13 99.1 0.0 0 8 ?? RL11:38AM 0:00.00 [idle: cpu1] root 12 98.0 0.0 0 8 ?? RL11:38AM 0:54.54 [idle: cpu2] Is it still something that I should disable, and, if so, how in 6.x? Thx Marc G. Fournier Hub.Org Networking Services (http://www.hub.org) Email: [EMAIL PROTECTED] Yahoo!: yscrappy ICQ: 7615664 ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
RE: Hyperthreading in 6.x ... still frowned upon?
In 4.x, it was a 'shut it off' sort of deal .. my new amd64 don't appear to have it enabled, but my older i386 server that I just upgraded to 6.x does: Is it still something that I should disable, and, if so, how in 6.x? Can you disable it in the BIOS or do you dual boot this machine? ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Hyperthreading in 6.x ... still frowned upon?
Marc G. Fournier wrote: In 4.x, it was a 'shut it off' sort of deal .. my new amd64 don't appear to have it enabled, but my older i386 server that I just upgraded to 6.x does: user pid %cpu %mem vsz rss tt state starttime command root 14 104.0 0.0 0 8 ?? RL11:38AM 0:55.02 [idle: cpu0] root 11 99.1 0.0 0 8 ?? RL11:38AM 0:00.00 [idle: cpu3] root 13 99.1 0.0 0 8 ?? RL11:38AM 0:00.00 [idle: cpu1] root 12 98.0 0.0 0 8 ?? RL11:38AM 0:54.54 [idle: cpu2] Is it still something that I should disable, and, if so, how in 6.x? You should test it for the workloads you have, but most of the time, HT isn't especially helpful. AMD64 CPUs come in dual-core format rather than HT-enabled. If you've seen HT or HTT applied to an AMD system, it's likely an abbreviation for HyperTransport or HyperTransport Technology. -- -Chuck ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
RE: Hyperthreading in 6.x ... still frowned upon?
On Wed, 3 May 2006, Zimmerman, Eric wrote: In 4.x, it was a 'shut it off' sort of deal .. my new amd64 don't appear to have it enabled, but my older i386 server that I just upgraded to 6.x does: Is it still something that I should disable, and, if so, how in 6.x? Can you disable it in the BIOS or do you dual boot this machine? Unfortunately, this is a remote server, and not HP, so getting at the BIOS is tricky ... :( Is there a sysctl variable that can be set for this? Marc G. Fournier Hub.Org Networking Services (http://www.hub.org) Email: [EMAIL PROTECTED] Yahoo!: yscrappy ICQ: 7615664 ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Hyperthreading in 6.x ... still frowned upon?
On Wed, May 03, 2006 at 01:06:24PM -0300, Marc G. Fournier wrote.. On Wed, 3 May 2006, Zimmerman, Eric wrote: In 4.x, it was a 'shut it off' sort of deal .. my new amd64 don't appear to have it enabled, but my older i386 server that I just upgraded to 6.x does: Is it still something that I should disable, and, if so, how in 6.x? Can you disable it in the BIOS or do you dual boot this machine? Unfortunately, this is a remote server, and not HP, so getting at the BIOS is tricky ... :( Is there a sysctl variable that can be set for this? As a matter of curiosity: do you run RILOE to get console access on your HPs? -- Wilko Bulte [EMAIL PROTECTED] ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Hyperthreading in 6.x ... still frowned upon?
On Wed, 3 May 2006, Wilko Bulte wrote: On Wed, May 03, 2006 at 01:06:24PM -0300, Marc G. Fournier wrote.. On Wed, 3 May 2006, Zimmerman, Eric wrote: In 4.x, it was a 'shut it off' sort of deal .. my new amd64 don't appear to have it enabled, but my older i386 server that I just upgraded to 6.x does: Is it still something that I should disable, and, if so, how in 6.x? Can you disable it in the BIOS or do you dual boot this machine? Unfortunately, this is a remote server, and not HP, so getting at the BIOS is tricky ... :( Is there a sysctl variable that can be set for this? As a matter of curiosity: do you run RILOE to get console access on your HPs? If RILOE == iLO via SSH ... most definitely ... can't rave enough about it, just wish I could afford to replace all the *old* servers with these, would reduce my 'remote admin stress levels' by half easily ... Marc G. Fournier Hub.Org Networking Services (http://www.hub.org) Email: [EMAIL PROTECTED] Yahoo!: yscrappy ICQ: 7615664 ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Hyperthreading in 6.x ... still frowned upon?
At 11:36 AM 5/3/2006, Chuck Swiger wrote: Marc G. Fournier wrote: In 4.x, it was a 'shut it off' sort of deal .. my new amd64 don't appear to have it enabled, but my older i386 server that I just upgraded to 6.x does: user pid %cpu %mem vsz rss tt state starttime command root 14 104.0 0.0 0 8 ?? RL11:38AM 0:55.02 [idle: cpu0] root 11 99.1 0.0 0 8 ?? RL11:38AM 0:00.00 [idle: cpu3] root 13 99.1 0.0 0 8 ?? RL11:38AM 0:00.00 [idle: cpu1] root 12 98.0 0.0 0 8 ?? RL11:38AM 0:54.54 [idle: cpu2] Is it still something that I should disable, and, if so, how in 6.x? You should test it for the workloads you have, but most of the time, HT isn't especially helpful. AMD64 CPUs come in dual-core format rather than HT-enabled. If you've seen HT or HTT applied to an AMD system, it's likely an abbreviation for HyperTransport or HyperTransport Technology. An Intel technical rep that gave a presentation on upcoming Intel VT technology in processors (Virtualization Technology) that I attended indicated that Hyperthreading was really designed to start getting programmers to program threading into their applications in preparation of dual core processors that we now have. Hyperthreading will likely be removed in future processors now that dual core technology is standard. In some instances it created a slight performance boost. Hyperthreading is known to hurt performance under high loads because it diminishes the amount of cache available for each thread. Many times, having no Hyperthreading but more CPU cache available increases performance under high loads. I typically disable Hyperthreading on all my servers as they are dual processor or dual core/dual processor or better anyway. I tend to get better results (with my applications) without Hyperthreading. I've been experimenting with leaving it on with my workstation as it's not a dual core or dual processor. The reason hyperthreading frowned upon in multiuser scenarios of FreeBSD is due to a vulnerability found in Hyperthreading: http://lists.freebsd.org/pipermail/freebsd-security/2005-May/002903.html Hyperthreading needs to be disabled in the BIOS. Often is referred to as a Virtual Processor in the BIOS. Vinny Abello Network Engineer Server Management [EMAIL PROTECTED] (973)300-9211 x 125 (973)940-6125 (Direct) PGP Key Fingerprint: 3BC5 9A48 FC78 03D3 82E0 E935 5325 FBCB 0100 977A Tellurian Networks - The Ultimate Internet Connection http://www.tellurian.com (888)TELLURIAN Courage is resistance to fear, mastery of fear - not absence of fear -- Mark Twain ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Hyperthreading in 6.x ... still frowned upon?
On Wed, May 03, 2006 at 02:12:45PM -0300, Marc G. Fournier wrote.. On Wed, 3 May 2006, Wilko Bulte wrote: On Wed, May 03, 2006 at 01:06:24PM -0300, Marc G. Fournier wrote.. On Wed, 3 May 2006, Zimmerman, Eric wrote: In 4.x, it was a 'shut it off' sort of deal .. my new amd64 don't appear to have it enabled, but my older i386 server that I just upgraded to 6.x does: Is it still something that I should disable, and, if so, how in 6.x? Can you disable it in the BIOS or do you dual boot this machine? Unfortunately, this is a remote server, and not HP, so getting at the BIOS is tricky ... :( Is there a sysctl variable that can be set for this? As a matter of curiosity: do you run RILOE to get console access on your HPs? If RILOE == iLO via SSH ... most definitely ... can't rave enough about it, just wish I could afford to replace all the *old* servers with these, would reduce my 'remote admin stress levels' by half easily ... Yup.. they are nice ;-) -- Wilko Bulte [EMAIL PROTECTED] ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Hyperthreading in 6.x ... still frowned upon?
On Wed, May 03, 2006 at 11:42:18AM -0300, Marc G. Fournier wrote: In 4.x, it was a 'shut it off' sort of deal .. my new amd64 don't appear to have it enabled, but my older i386 server that I just upgraded to 6.x does: I am not sure I understood your problem correctly... Do you want to enable hyperthreading on amd64? But they have no such thing. Intel only. -- Spartak Radchenko SVR1-RIPE ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
RE: Hyperthreading in 6.x ... still frowned upon?
Spartak Radchenko wrote: On Wed, May 03, 2006 at 11:42:18AM -0300, Marc G. Fournier wrote: In 4.x, it was a 'shut it off' sort of deal .. my new amd64 don't appear to have it enabled, but my older i386 server that I just upgraded to 6.x does: I am not sure I understood your problem correctly... Do you want to enable hyperthreading on amd64? But they have no such thing. Intel only. you do know that EM64T Xeons *DO* have hyperthreading, and (can) run an amd64 kernel? $ sysctl hw hw.machine: amd64 hw.model: Intel(R) Xeon(TM) CPU 3.00GHz hw.ncpu: 4 -- Larry Rosenman http://www.lerctr.org/~ler Phone: +1 512-248-2683 E-Mail: ler@lerctr.org US Mail: 430 Valona Loop, Round Rock, TX 78681-3893 ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Hyperthreading in 6.x ... still frowned upon?
On Wed, May 03, 2006 at 01:36:04PM -0400, Vinny Abello wrote: An Intel technical rep that gave a presentation on upcoming Intel VT technology in processors (Virtualization Technology) that I attended indicated that Hyperthreading was really designed to start getting programmers to program threading into their applications in preparation of dual core processors that we now have. That sounds like an interesting interpretation of history :-) I typically disable Hyperthreading on all my servers as they are dual processor or dual core/dual processor or better anyway. I tend to get better results (with my applications) without Hyperthreading. I've been experimenting with leaving it on with my workstation as it's not a dual core or dual processor. In my experience it's almost always a net loss too. One should measure for oneself though. Kris pgpPPdZBFM2Fe.pgp Description: PGP signature
Re: Hyperthreading in 6.x ... still frowned upon?
On Wed, May 03, 2006 at 01:44:02PM -0500, Larry Rosenman wrote: Spartak Radchenko wrote: On Wed, May 03, 2006 at 11:42:18AM -0300, Marc G. Fournier wrote: In 4.x, it was a 'shut it off' sort of deal .. my new amd64 don't appear to have it enabled, but my older i386 server that I just upgraded to 6.x does: I am not sure I understood your problem correctly... Do you want to enable hyperthreading on amd64? But they have no such thing. Intel only. you do know that EM64T Xeons *DO* have hyperthreading, and (can) run an amd64 kernel? Of course. So amd64 means FreeBSD platform in the original posting, not hardware? Ok, thanks. It was not evident to me. -- Spartak Radchenko SVR1-RIPE ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Hyperthreading in 6.x ... still frowned upon?
On Wed, 3 May 2006, Spartak Radchenko wrote: On Wed, May 03, 2006 at 11:42:18AM -0300, Marc G. Fournier wrote: In 4.x, it was a 'shut it off' sort of deal .. my new amd64 don't appear to have it enabled, but my older i386 server that I just upgraded to 6.x does: I am not sure I understood your problem correctly... Do you want to enable hyperthreading on amd64? But they have no such thing. Intel only. Nope, disable it on i386 ... Marc G. Fournier Hub.Org Networking Services (http://www.hub.org) Email: [EMAIL PROTECTED] Yahoo!: yscrappy ICQ: 7615664 ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Hyperthreading in 6.x ... still frowned upon?
On Wed, 3 May 2006, Spartak Radchenko wrote: On Wed, May 03, 2006 at 01:44:02PM -0500, Larry Rosenman wrote: Spartak Radchenko wrote: On Wed, May 03, 2006 at 11:42:18AM -0300, Marc G. Fournier wrote: In 4.x, it was a 'shut it off' sort of deal .. my new amd64 don't appear to have it enabled, but my older i386 server that I just upgraded to 6.x does: I am not sure I understood your problem correctly... Do you want to enable hyperthreading on amd64? But they have no such thing. Intel only. you do know that EM64T Xeons *DO* have hyperthreading, and (can) run an amd64 kernel? Of course. So amd64 means FreeBSD platform in the original posting, not hardware? Ok, thanks. It was not evident to me. This is correct ... we have two HP Dual Xeon 64bit servers, both running FreeBSD 6.x/amd64 ... those ones run without an issue, and don't have HyperThreading enabled ... they are slightly older CPUs, so aren't Dual-Core either ... Marc G. Fournier Hub.Org Networking Services (http://www.hub.org) Email: [EMAIL PROTECTED] Yahoo!: yscrappy ICQ: 7615664 ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
