----- Original Message ----- From: "Tom Marchant" <[EMAIL PROTECTED]> Newsgroups: bit.listserv.ibm-main To: <IBM-MAIN@BAMA.UA.EDU> Sent: Tuesday, July 17, 2007 10:08 PM Subject: Re: PSI MIPS (was: Links to decent 'why the mainframe thrives' article)
> Process size is a limiting factor for performance. One can find devices manufactured in a process one or two generations back that perform just as well as one manufactured on a current process generation, depending upon the design (Itanium vs. x86, for example). So process size is not an indication of performance, particularly across architectures. > > How can you say that? Haven't you read the literature? The fact is that > both of these do provide performance benefits. Yes, I have read them. My understanding is that it allows for lower leakage and power consumption. This, in turn, *may* allow for higher clocked devices. However, performance at a given clock speed does not increase and there may be other limiting factors in clockspeed. As I said, Intel, for example, does not use SOI and seems to be producing very high clockrate devices without it, which (currently) outperform their rival AMD, who *does* use IBM's SOI process. > > >and has nothing at all to do with feature size. > > Didn't you just say that process (feature) size is not an indicator of > performance? Yes, I mistyped. > > >It was > >supposed to help with leakage, but Intel seems to be doing quite will > >without these. > > As Timothy pointed out, Intel is in fact using copper. Has been for years. > > >Lest you misunderstand me - I am not trying to say that Intel is 'better' > >than IBM, nor the other way around. > > That's right, you didn't say "better". You said "faster". More precisely, > you said, "The mainframe MPU *is* slower than other processor platforms." Yes, and I recanted if you recall. Now I am looking for any data that would help identify whether the perception is, in fact, true or not. Simply stating that IBM is a technology leader, and pointing to their manufacturing process provides no insight into this - and that is what I was pointing out in my rebuttal to you. > > > ... However, IBM is positioning > >the mainframe to compete in some of the same markets that x86 competes. > > What do you mean by that? Are you talking about Linux on z? Or are you > talking about the larger servers that are being constructed from 86 > processors in the hope of competing with mainframes? I'm talking about positioning the mainframe as a web/database server, and a Linux platform. > > > > >Using the argument that IBM is a leader in technology, and therefore z9 must > >be better than x86 is ludicrous, if that was your point. > > I most certainly didn't say that, and I think you know it. Red herrings are > not rational arguments. Then I have no idea what your point was in making the statement about IBM's process. TSMC is a huge foundry, and uses advanced manufacturing process - but this has nothing at all to do with whether they are a 'technology leader' able to design and produce advanced microprocessors that can compete with IBM or Intel. > > > > >I mentioned that I find it hard to believe that IBM would invest in > >mainframe performance to the extent that x86 manufacturers would, > >considering the difference in the competitivness of the markets. > > IBM invests where the money is. The mainframe business is a profitable one. I am comparing the pace of improvement in x86 with the mainframe. The IT Jungle article says that installed mainframe MIPS has increased 4 fold over 7 years. I showed that in the same time period, x86 performance has increased over 8 fold. We still aren't getting an apples to apples comparison because it doesn't tell us what the highest performing mainframe processor was in 2000 vs today. My point was that in a market where there isn't the intense competition that there is less incentive to pour money into it. Intel and AMD *have* to, lest the other one grab huge market share (as Intel saw AMD do with the Opteron, and now AMD is seeing Intel do with the Core 2 processors). IBM seems to be in an enviable position with the mainframe where there isn't any real direct competition, yet. > > >It was > >stated that IBM invests $1.2B annually on mainframe R&D (hardware, software > >and services). Intel, on the other hand, spends almost $6B on their > >semiconductor business alone. It should not be surprising that Intel is > >also a leader in technology - even if their primary product is the lowly x86 > >based processors. > > Yes, Intel is another leader in the semiconductor industry. Not, IMO, in > computer architectures, though. The iAPX 432 was a notable exception. Agreed. But my intent was not to compare IBM and Intel, but z9 with other architectures - such as x86, Itanium and POWER. x86 being the most common, and Itanium only because it was used in the PSI systems. > > >As for fault-tolerant systems, Stratus and NEC offer them (and likely > >others). > > Tandem was first with real fault tolerance as we know it today. > > >The I/O performance that was once the realm of the mainframe is now > >available for other platforms as well. > > There's another assertion. Have you any data to back it up? What kind of > I/O bandwidth can these systems handle? A z9 has from 16 to 64 STI busses, > each capable of transferring 2.7 Gbytes/second. Well, I had heard a few years back that a p690 could support a sustained I/O rate of somewhere around 22GB/s, and a maximum that was higher. I just looked and that system has been withdrawn from marketing for a couple of years. This is, of course, an IBM (POWER based) system. I'm sure the replacement has better throughput, though I haven't taken the time to look it up. > > >So, while the mainframe still enjoys a relatively comfortable niche, I don't > >think mainframers should be too smug about it. x86 processors are not just > >good for word processing, despite some comments to that effect. Making > >snide, derogatory remarks about x86 or other platforms is just as foolish as > >PC people making derogatory comments about the mainframe. > > > >It would be nice if people would post information that would further the > >dialog rather than simply to defend a position. > > Please do, if you have any data. So far you have provided precious little. I'm waiting too... > > So do I. I'm still waiting for you to back up your assertions. I'm trying to. So, let's look at one of yours and I'd like to get some specifics that don't include vague references to manufacturing process: "Those improvements are indeed quite stunning. Far from "keeping pace," mainframe technology has been leading." The context, of course, was about keeping pace with other platforms. I've provided links to benchmark results showing a greater than 8-fold improvement from 2000 to 2006. I've not seen any data regarding performance improvements for mainframe processors over that time except for the "4-fold increase in installed MIPS" between 2000 and 2007. There is no way to know how that relates to individual processors. If you have any data, that would be nice to hear. IOW, the assertion is that mainframe technology has been leading with only a link to mainframe information - nothing comparing with other platforms. > > And, by the way, the SPECjbb that you keep mentioning is purely a CPU > benchmark. It is designed to run without performing any I/O. I don't think > there's anyone who buys a mainframe for its sheer processing power. The original question was "Why do people think the mainframe processor is slower", as was stated in the ARS Technica article. This is a common perception, whether correct or not. Perhaps the question would be - "why do people migrate off the mainframe if it is so powerful?". According to the data in the referenced article, most of the growth in mainframes has been due to the specialty engines - which seems to be the same market that traditional Unix servers are in. These servers *are* purchased, in part, for their processing power. Hence my reference to industry standard benchmarks used by vendors and customers to compare them. After all, IBM does use these benchmarks for POWER and x86 based systems that they sell into those markets. Regards, Dean > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
