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From: Terje Mathisen "terje.mathisen at on 18 Apr 2010 15:42 nmm1(a)cam.ac.uk wrote: > Well, yes, but that's no different from any other choice. As I have > posted before, I favour a heterogeneous design on-chip: > > Essentially uninteruptible, user-mode only, out-of-order CPUs > for applications etc. > Interuptible, system-mode capable, in-order CPUs for the kernel > and its daemons. This forces the OS to effectively become a message-passing system, since every single os call would otherwise require a pair of migrations between the two types of cpus. I'm not saying this would be bad though, since actual data could still be passed as pointers... Terje -- - <Terje.Mathisen at tmsw.no> "almost all programming can be viewed as an exercise in caching"
From: =?ISO-8859-1?Q?Niels_J=F8rgen_Kruse?= on 18 Apr 2010 15:49 Andy "Krazy" Glew <ag-news(a)patten-glew.net> wrote: > On 4/18/2010 4:57 AM, Niels J�rgen Kruse wrote: > > Andy "Krazy" Glew<ag-news(a)patten-glew.net> wrote: > > > >> The ARM Cortex A9 CPU is out-of-order, and is becoming more and more > >> widely used in things like cell phones and iPads. > > > > Cortex A9 is not shipping in any product yet (I believe). Lots of > > preannouncements though. The Apple A4 CPU is currently believed to be a > > tweaked Cortex A8, perhaps related to the tweaked A8 that Intrinsity did > > for Samsung before being acquired by Apple. > > Ref? > > Most of the articles that I have seen say that the iPad A4 is a Cortex A9. That would have been the early speculation. A more current view is <http://www.anandtech.com/show/3640/apples-ipad-the-anandtech-review/16> and the next page with benchmarks. The A4 is about half the speed of an Atom N450 (512K Cache, 1.66 GHz) on a web page load benchmark. The hype around the Cortex A9 would lead us to expect better. -- Mvh./Regards, Niels J�rgen Kruse, Vanl�se, Denmark
From: Muzaffer Kal on 18 Apr 2010 15:56 On Sun, 18 Apr 2010 11:25:38 -0700, "Andy \"Krazy\" Glew" <ag-news(a)patten-glew.net> wrote: >On 4/18/2010 4:57 AM, Niels J�rgen Kruse wrote: >> Andy "Krazy" Glew<ag-news(a)patten-glew.net> wrote: >> >>> The ARM Cortex A9 CPU is out-of-order, and is becoming more and more >>> widely used in things like cell phones and iPads. >> >> Cortex A9 is not shipping in any product yet (I believe). Lots of >> preannouncements though. The Apple A4 CPU is currently believed to be a >> tweaked Cortex A8, perhaps related to the tweaked A8 that Intrinsity did >> for Samsung before being acquired by Apple. > >Ref? > >Most of the articles that I have seen say that the iPad A4 is a Cortex A9. Based on my count of google results, A8 is slightly ahead of A9 in terms of what core is actually in A4. -- Muzaffer Kal DSPIA INC. ASIC/FPGA Design Services http://www.dspia.com
From: jgd on 18 Apr 2010 15:56 In article <4BCB60FF.9030306(a)patten-glew.net>, ag-news(a)patten-glew.net ( Glew) wrote: > Itanium was designed by people who thought that P6-style out-of-order > was going to fail. Ah, that makes sense. Thanks. In some ways the Itanium method of running several instructions at once seems more "obvious". I was convinced by it at first, and only gradually realised that in spite of its intuitive appeal, it did not work well in this example. > In many ways they were the P6 competitors. P6 was Oregon. Itanium > was California. Many Itanium folk were from P5. If they had left P5 in the relatively early days, when clock speeds were still under 100MHz, their implicit assumptions about speeds and bandwidths make more sense. Thanks again. -- John Dallman, jgd(a)cix.co.uk, HTML mail is treated as probable spam.
From: Robert Myers on 18 Apr 2010 16:06
Andy "Krazy" Glew wrote: > > Hmm... From my point of view, the Itanium was the first computer > architecture driven mainly by academics with PhDs. > > Its immediate predecessor, the P6, has only one PhD amongst its 5 > primary architects. (Bob Colwell.) > > Itanium had a lot more people who had piled it higher and deeper. I am very grateful to the PhD academics who tolerated my eccentricities as I pursued my PhD and for the education they gave me. I am very grateful to the PhD academics who helped me to develop as an independent thinker with some competence and self-confidence as I worked outside academia. I am very grateful to those who actually *do* things, with or without a PhD, who continue to be generous with their knowledge and experience. Scientists and engineers at every level of education are not the most adept at negotiating political and social landscapes. I'm glad to have people to talk to. As to what is the foolproof way to manage the diverse range of talent that is a multi-billion dollar R&D effort, I don't think there is such a thing. Robert. |