How rapidly can a z17 dispatch instructions? That's a significant factor in estimating instructions.
Long ago in a galaxy far away, IBM used to include timing formulae in functional specifications. The was a clear trend that when you looked at a larger or newer machine, the formulae got more complicated. I shudder to think of how complicated timing formulae for the z17 would. In practice, there was never a way to measure the performance of a computer, only its performance on specific benchmarks. -- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 עַם יִשְׂרָאֵל חַי נֵ֣צַח יִשְׂרָאֵ֔ל לֹ֥א יְשַׁקֵּ֖ר ________________________________________ From: IBM Mainframe Discussion List on behalf of Abe Kornelis Sent: Thursday, April 17, 2025 1:24 AM To: [email protected] Subject: Re: z17 External Message: Use Caution All, I have been surprised nobody has mentioned the parallel execution. From the announcement up to [decimal] ten instructions can be in progress simultaneously, and up to four instructions can be fetched and decoded in parallel. Doing ten instructions simultaneously would imply an effective speed of 55GHz. Obviously, that limit of ten will rarely be reached, but only one at a time is probably rather rare as well these days. I'd have liked to see some metrics from IBM testing, if only to please the taste buds :-) Kind regards & Happy programming, Abe Kornelis ========== On 17/04/2025 06:27, Timothy Sipples wrote: > Steve Beaver wrote: >> We all know the z17 has been announced. >> What I am disappointed in is the CP's have not gone faster than 5.5 Ghz. >> I know the z17 is an evolution, but why have they not gotten faster? > The main processors’ clock speed has in fact increased from 5.2 GHz in the > IBM z16 to 5.5 GHz in the IBM z17. > > Please note that these systems are designed to operate continuously for their > entire lives at these extremely high clock speeds provided your data center > doesn't drift outside typical industry standard environmental limits. > (Outside environmental limits the system will defend itself if/as necessary, > first by slowing down then by shutting down. And the system will try to warn > operators that's what's happening — and notify IBM if you have Remote Support > Facility a.k.a. "Call Home" enabled.) It's not some "turbo mode" clock speed > that you only get for 5 seconds after you start using the processors. > > As others have astutely pointed out, the clock speed is only one aspect of > processor performance and throughput. Many other design factors are at least > as important. However, if you'd like to applaud the amazing designers and > engineers who figured out how to increase the lofty clock speed to be even > loftier, I'm sure they'd appreciate it. > > ————— > Timothy Sipples > Senior Architect > Digital Assets, Industry Solutions, and Cybersecurity > IBM Z/LinuxONE, Asia-Pacific > [email protected] > > > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
