Author: Robert Hyatt
Date: 15:16:55 11/18/02
Go up one level in this thread
On November 18, 2002 at 14:44:24, Vincent Diepeveen wrote: >On November 18, 2002 at 13:25:41, Robert Hyatt wrote: > >which speed are those P4 Xeons clocked at your uni? 2.4 and 2.8, why??? both are duals. And we have a 2.2 also I think although I don't know if it is doing hyper-threading... > >>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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