Author: Vincent Diepeveen
Date: 11:44:24 11/18/02
Go up one level in this thread
On November 18, 2002 at 13:25:41, Robert Hyatt wrote: which speed are those P4 Xeons clocked at your uni? >On November 18, 2002 at 11:01:05, Vincent Diepeveen wrote: > >>On November 18, 2002 at 10:58:35, Robert Hyatt wrote: >> >>>On November 18, 2002 at 10:15:53, Vincent Diepeveen wrote: >>> >>>>On November 18, 2002 at 01:28:17, Terry McCracken wrote: >>>> >>>>>On November 17, 2002 at 13:58:43, Vincent Diepeveen wrote: >>>>> >>>>>>Hello, >>>>>> >>>>>>If i read the below section of the intel programming guide very well, >>>>>>then i interpret that as: >>>>>> >>>>>> a) only the Xeon MP has hyperthreading and not the normal P4s, >>>>>> not even P4s sold as Northwoods. >>>>>> >>>>>> b) even the Xeon MP you should not assume that it supports hyper >>>>>> threading. In fact something that gets sold as Xeon MP you should >>>>>> still not assume that it supports hyper threading, but instead >>>>>> one must assume that only after specifically questionning the cpu >>>>>> whether it can do it. >>>>>> >>>>>>Intel IA-32 programming manual. Page 247 (of 780): >>>>>>" >>>>>>7.6.1 Implementation of Hyper-Threading Technology in IA-32 Processors >>>>>> >>>>>>Intel's Hyper-threading Technology was introduced into the IA-32 architecture >>>>>>in the Intel Xeon processor MP and in the later steppings of the Intel Xeon >>>>>>processor. Both of these processors implement Hyper-Threading Technology with 2 >>>>>>logical processors per physical processor. When reading the following sections >>>>>>(and other sections in this book that refer to this technology), assume that all >>>>>>references to the implementation of Hyper-Threading Technology in the Intel Xeon >>>>>>processor MP also apply to those later steppings of the Intel Xeon processor >>>>>>that implement Hyper-Threading Technology. >>>>>> >>>>>>Intel recommends that software not rely on IA-32 processor names to determine >>>>>>whether a processor supports Hyper-Threading Technology; but instead, it should >>>>>>use the CPUID instruction as described in Section 7.6.5, "Detecting >>>>>>Hyper-Threading Technology". >>>>>>" >>>>>> >>>>>>Vincent >>>>> >>>>>Careful, Intel sues! >>>> >>>>Not at all. They now claim only the > 3Ghz P4s will have hyperthreading >>>>enabled, but that's an easy claim, because i cannot check it as the >>>>fastest P4 i can test now is 2.53Ghz. With some luck soon also 2.8Ghz P4. >>>> >>>>At the time the > 3 Ghz P4s are there within say a 6 months or so, >>>>of course those statements will have been forgotten. >>>> >>>>The only official statement is that the group of processors which >>>>*might* support SMT is the Xeon MPs and only >>>>after you ask the cpu a CPUID and when that response is positive >>>>*then* it supports it. >>>> >>>>So they give ZERO garantuee simply yet. >>>> >>>>Best regards, >>>>Vincent >>> >>> >>>It isn't only the xeon MT. The MTs are certified for 4-way and 8-way, but the >>>other xeons are also doing hyperthreading. The 2.8's in particular. This is >>>from experience, not from guessing, btw... >> >>Not a single P4 i tested so far with the 'smt' turned on is doing it Bob, >>of course i do not do a CPUID in DIEP to check whether the chip is supporting >>it. >> >>The statement from intel is very clear. *nowhere* they garantuee it works >>and at the Xeon MP it might work after you do a CPUID. >> >>The results posted by Nalimov here are all from dual Xeon MPs. >> >>Best regards, >>Vincent > > >There are three kinds of intel processors. > >PIV > >PIV xeon > >xeon MP > >the last two definitely have hyper-threading. I have two here (not MPs as I >don't have any >quads at the faster clock rates yet). > >I'm talking about the xeon, not the xeon MP. And they definitely have >hyper-threading >support... > >And I don't think Eugene's machines were xeon MPs... the MPs are pricier and >really >intended for 4-way and 8-way machines... The duals I have here are _not_ MP >processors.
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