Linked by Thom Holwerda on Wed 14th Apr 2010 23:51 UTC
IBM This article describes a real-word software port, with examples of how various porting challenges are resolved. If you are a software developer porting software to UNIX, you will find these techniques invaluable in avoiding common pitfalls, resolving bugs, and improving your productivity.
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foobar
Member since:
2006-02-07

""You are not accounting for cores/chips/processors correctly. A 64 processor z10 is actually 64 cores. An 8 socket nehalem is 64 cores. If you want per core performance, then it is 3200/64 = 50 emulated mips, and 50 * 5 = 250. So you need 120 nehalem cores by your hoakie numbers."


I didnt get that. Could you explain again? It seems that you claim that 64 Mainframe CPUs have in total: 64 cores? Then it must mean that Mainframe CPUs are single cores. I thought they were quad core?
"

Yup, I didn't think that you would actually look at the redbook that I linked. The big z10 machine has 4 books. Books have many chips on the MCM. 5 of them are processor chips. Each processor chip has 4 cores. There are a grand total of 80 cores in a z10. After subtracting 11 for SAPs, 2 for spares, and 3 for cores that don't pass manufacturing tests, there are 64 cores for customers to run their favorite operating systems on.

In IBM-speak a way or a processor is a core. It's been that way for 10 years with the i/p/z stuff. You are very quick to make claims about how bad IBM is, yet you don't know such details? Are you making judgments based on you're own personal biases, or the technical facts?

Why don't you read a little about the hardware that you are bashing? Next time we can have a better argument ;)

Who (except IBM) is interested in performance per core? I am comparing one Mainframe cpu vs Nehalem-EX cpu. Not core vs core. I dont claim that Nehalem-EX core is faster than Mainframe core. (This is typical FUD from IBM: shift focus from cpu vs cpu, to something else, such as core vs core.)


If you want to argue cpu vs cpu, then you need to state that up front instead of making unsubstantiated claims and then babbling about extrapolated emulation performance.

Like it or not. In the real world, outside of the desktop, hobby realm, there's an awful lot of applications that are still priced per core. This is true for all platforms.

Could please explain again, why an Nehalem-EX cpu is slower than a Mainframe CPU? Note that I wrote "CPU" not, core, or ALU, or registers, or whatever. Just because one part of the CPU is faster - it doesnt say anything about the entire cpu. "My car has a better ignition mechanism than your car, therefore my car is faster than yours" - plain FUD. You must compare car vs car, not some small part vs another part. No one is interested in that small part.


Could we please back up and remember what this thread is about? You made an unsubstantiated claim about a "dog slow", and "1/10th of the speed":

As I have shown, a modern x86 cpu is roughly 10x faster than a Mainframe CPU. Why port from fast x86 cpus, to dog slow cpus? I dont understand why you want to get 1/10th of the speed?


Then when I challenged you, you built an argument on a Wikipedia post that had extrapolated performance numbers. Somehow you twisted the numbers to conclude that an 8 socket nehalem machine can replace a fully populated z10.

If you would have kept your argument brief and used technical facts, I would have admitted that 4 z10 cores on a chip vs 8 Nehalem cores on a chip is probably 60%. But you chose to talk in circles about emulation and leave out important details about each machine.

""While we're throwing around hoakie numbers, lets account for the other cores in the z10. Not channel cards, but the z10 cores characterized as SAPs and CFs. Since, IBM actually measured that 30,000 MIPs number, we should include the cores doing IO. For the biggest machine, that's another 11 cores. 11 * (30,500/64) = 5200 MIPS. So we can estimate that a z10 is really capable of 35,700 MIPS."



Come on, this is really silly of you. You dont want to do this comparison. You would be really upset if I claimed (just like you do): "Well, the latest Nvidia card is capable of TeraFlops, therefore the Nehalem-EX server must be faster than the Mainframe server".

Now THAT comparison would be hoakie, dont you agree? But it is ok if IBMers do this comparison, right?
"

I wouldn't have used the word "hoakie" if I was serious. Remember, you started the silliness with extrapolated emulation numbers when you really wanted to compare native applications.

BTW, I talked with another IBMer who claimed that: despite you need four POWER6 cpus to match two Intel (ordinary) Nehalem, the POWER6 is faster. Because it has higher clocked core, or something weird. I never understood his logic. It was really weird. Then he started to talk about pricing, the POWER6 software licenses would be cheaper, therefore the POWER6 is faster. I dont get it, where all IBMers find that weird stuff to say? The funny thing is, they BELIEVE it is true! :o) Even today he is convinced that POWER6 is faster than Nehalem. I couldnt talk him out of it. No matter what I said, he refused to listen. :o)


At this point, I really don't believe you. I think you're making stuff up now. Anecdotal evidence is an oxymoron. See what happens when I change a few words:

BTW, I talked with another Sunshiner who claimed that: despite you need four Niagara cpus to match two Intel (ordinary) Nehalem, the Niagara is faster. Because it has lower clocked core, or something weird. I never understood his logic. It was really weird. Then he started to talk about pricing, the Niagara software licenses would be cheaper, therefore the Niagara is faster. I dont get it, where all Sunshiners find that weird stuff to say? The funny thing is, they BELIEVE it is true! :o) Even today he is convinced that Niagara is faster than Nehalem. I couldnt talk him out of it. No matter what I said, he refused to listen. :o)

Reply Parent Score: 1

Kebabbert Member since:
2007-07-27

"...there are 64 cores for customers to run their favorite operating systems on.

In IBM-speak a way or a processor is a core. It's been that way for 10 years with the i/p/z stuff. You are very quick to make claims about how bad IBM is, yet you don't know such details? Are you making judgments based on you're own personal biases, or the technical facts?"

Ok, this explains why the Mainframe cpus are dog slow. A Mainframe cpu with one core, vs a 8-core Nehalem-EX. So, 64 Mainframe cpus, could in theory be replaced with 8 cpus that are each, 8-core. An 8-socket Nehalem-EX server has 64 cores in total. Ergo, you need roughly 8-socket Nehalem-EX to reach 64 cores. Here we have another anecdoctical evidence that 8-socket Nehalem-EX with 64 cores, matches 64 single core Mainframe cpus, provided by you.

I dont think you claim that a cpu with one core, can match a cpu with 8-cores, do you? This would of course be silly. If it were true, you would talk about performance unheard of. That is not realistic.

Regarding the technical details about Mainframes, well, I repeat what other more knowledgeable guys claim. They are certainly much more knowledgeable than both you and me. One guy ports Linux to Mainframes and he has experience of Linux on x86 vs Linux on Mainframes, the other guy writes an Emulator for Mainframes. Certainly they know much more than both you and me, and I hardly think you claim they are wrong? That is the reason that I dont know too much about legacy dog slow Mainframe cpu. Besides, who wants to spend time learning about dog slow dinosaurs? I admit Mainframes are good at I/O, but which computer isnt given all the extra I/O hardware that Mainframe has?





"If you want to argue cpu vs cpu, then you need to state that up front instead of making unsubstantiated claims and then babbling about extrapolated emulation performance.

Like it or not. In the real world, outside of the desktop, hobby realm, there's an awful lot of applications that are still priced per core. This is true for all platforms."

I thought I claimed since the very first beginning that "Mainframe cpus are dog slow"? I didnt talk about cores, did I? It is you that talk about cores, not me. And also, you talk about pricing. Why do you try to shift focus away from dow slow Mainframe cpus, to cores, and to pricing? Ive never talked about cores in the first place. You did. And know you try to make it look as if I didnt talk about cpu performance? What are you trying to do? Shift focus away from cpu performance?





"Could we please back up and remember what this thread is about? You made an unsubstantiated claim about a "dog slow", and "1/10th of the speed": "

Yes, I talked about Mainframe cpus being dog slow. And I provided calculations that showed that. Whereas you talks about core, and pricing, and what not.

Look, if I am wrong, then you can point out my errors in my calculations, right? You claim they are wrong, so point the errors out. Right now, you are just ducking the question. But both you and I know that Mainframe CPUs are dog slow. And I will tell this to everyone, on every site. As soon I gets the chance. I will provide links, and calculations. :o) Unless you prove me wrong of course. With hard numbers and facts. Not by ducking the question and talk about cores and pricing. I am only interested in performance of those slooooow Mainframe cpus. The fact, that IBM hides so well.





"I wouldn't have used the word "hoakie" if I was serious. Remember, you started the silliness with extrapolated emulation numbers when you really wanted to compare native applications. "

Look, I would be silly íf I counted a Nvidia card, when comparing a server's performance. But it is ok, you can do a similar thing. But hey, you are an IBMer. IBM is famous for FUDing, the first to employ FUD on a wider scale, according to wikipedia. It is ok, you just follow your company policy. I have lots of proof and links that show when IBMers FUD.





"At this point, I really don't believe you. I think you're making stuff up now. Anecdotal evidence is an oxymoron. See what happens when I change a few words: "

Jeez, I dont understand how you reason. Are you the same guy I discussed with? He did the same thing. Shifted focus to cores, and pricing.

What about "sunshiner"? Sun doesnt state what you claim. I am talking about IBMers FUD. You know your kin, you know that IBMers could make anything to look like anything. Of course I talking the truth. That guy, Jesper Frimann - an active IBMer, claimed that despite you need "four POWER6 to match two Nehalem the POWER6 is faster". He said something about (dont remember the weird logic, but something in the line of) "the power6 core is faster than a Nehalem core, and the power6 core has lower pricing because it is only two cores - therefore the POWER6 is faster".

This is similar to when IBM claims that IBM still has the TPC-C record today, because IBM is faster per core, than Sun's current world record. I mean, come on. Who has the current TPC-C world record? IBM or Sun? It is Sun. How can IBM claim that they have the world record, because they have more tpmC/core? That is just... weird? Isnt it? Who is at the top? It is Sun. If IBM can claim they still have the world record, then IBMer Jesper Frimann can claim that despite you need four POWER6 to match two 6-core Nehalem, the POWER6 is faster (because of fewer cores, and lower pricing). It is exactly the same line of strange logic. Just like your logic. Right? :o)

Reply Parent Score: 2