On Tue, 2004-07-06 at 18:19, James Wilkinson wrote: > ne wrote: > > Seems I stand corrected. I did some Googlle research myself and saw > > http://www.pcpro.co.uk/?http://www.pcpro.co.uk/news/news_story.php?id=59918. > > I quote: > > > > 'With its newly announced 'Nocona' Xeon processors - which clock > > speeds ranging from 2.8 to 3.6GHz - Intel brings 64-bit memory > > addressing to its 32-bit server processor. The aim is to provide > > greater support for the high-level number crunching tasks of the > > workstation market.' > > > > So I guess the question becomes do FC kernels have support for > > this chip yet? > > Jeff Vian objected: > > This is 64bit memory addressing on a 32bit processor. This is PLAINLY > > stated above. It is not likely the 64bit kernel will work. > > > > I also would guess the chipsets to support that are very new. > > Umm ... no. And yes. > > Decoding Intel statements is often an artform. > So you are saying they are spinning it, masking the true capabilities? Or are they spinning it, trying to say it does something it doesn't. I am confused, and so I stick with AMD as a rock solid workhorse. Rereading the info above it seems that even if this is a 64bit chip the kernel does not see it as 64 bit so ...... > In this case, Intel has literally spent billions of dollars on its > Itanium range, and billions more on support for it. Sales have not > been impressive. > > Intel has been carefully attempting to preserve sales on its 32 bit Xeon > workhorse range (which is extremely lucrative: until last year Intel had > basically no competition on the PC-based server market except at the > very low end), while spinning its 64 bit Itanium processor as being what > you really need if you want real computing power [1] while remaining > compatible with "the industry-standard 32 bit Intel architecture"[2]. > > AMD's Opteron has basically spoilt this. It is very competitive with > Xeon on single-CPU systems, scales much better than Xeon (largely due to > HyperTransport and the NUMA memory architecture), really has superb 32 > bit performance, and has 64 bit options (with the promise of even better > performance). So lots of people have been interested. > > Intel has responded by adding a (mostly) Opteron-compatible [3] 64 bit > mode to recent Pentium 4 based processors, and has started turning it > on in some of the most recent Xeons. It now has a problem: how does it > advertise its new 64 bit chips without cannibalising sales for Itanium? > > Its answer is statements like the one above: it's trying to portray the > 64 bit mode as solely about letting Xeons efficiently address lots of > memory, whereas Itanium is still about real power and the future of > computing, and what you want if you want real 64 bit support. Honest, > guv. > > In fact, although there are areas where Itanium makes sense, the market > is limited. At the moment, it's largely limited to more than eight-way > SMP boxes, in roles where they need fast access to shared memory (so > clustering won't work). > > Itanium was supposed to support this market, but it was supposed to do > so with chips that could be sold in PC quantities, and the forecasts for > the project assume these economies of scale. > > In the real world, the Intel AMD64 compatible processors are just as > much 64 bit processors as their AMD counterparts. > > Unfortunately, there are some hardware level differences between the > two platforms, which need to be reflected in the way the kernel handles > them [4]. I know there are patches in the current upstream kernel, > but I don't know whether they made it to the default x64-64 FC2 kernel, > nor whether the surrounding software knew about the possibility of > Intel x86-64 processors. So you're probably right, Jeff: these CPUs > may not be reliably handled in 64 bit mode until FC3. > > HTH, > > James. > > [1] Until recently this was a joke. These days, Itanium is becoming > competitive at certain tasks, especially those requiring lots of FPU. > > [2] But not if you want any speed out of your 32 bit programs... > > [3] It's supposed to be as compatible in 64 bits as it is in 32 bits: > at the moment, AMD doesn't have SSE3, while Intel doesn't have 3D-Now. > This is reputedly at the insistence of Microsoft, who didn't fancy > having to port to *four* processor families... > > [4] For example, Intel chipsets also don't have the IOMMU that 64 bit > AMD CPUs have. This isn't strictly an instruction set compatibility > issue, but the IOMMU is supposed to be very handy in supporting existing > hardware on systems with more than 4 GB of memory. > > -- > E-mail address: james@ | "Come on, son, give us your best shot." > westexe.demon.co.uk | -- Goliath >
