Re: zIIP MultiThreads
On Fri, 4 Sep 2020 09:22:09 -0700, Ed Jaffe wrote: >IMHO, if you need additional zIIP capacity for a production workload, it >probably makes more sense to configure another zIIP core online than it >does to enable MT=2. Agreed. SMT is a good thing to keep in your pocket for the emergency of "we need a little more zIIP capacity, but we can't purchase another zIIP right now". Don't use it as a substitute for real zIIP capacity. If you need zIIP capacity buy more zIIP capacity. It's relatively inexpensive. 1) The amount of extra throughput you'll get is variable depending on your workload mix. And the timing of the mix of workload. You can't use test to accurately predict production, you just have to try it. 2) MT=2 is effectively more/slower engines vs. fewer/faster engines. This is a trade-off that's ok to good for most workloads, but is worth bearing in mind. 3) The measurements are complicated estimates based on instruction counts seen with 1 and 2 threads active that are not well documented. Most importantly, the reported zIIP time becomes MT1ET: the estimated time the work would have consumed on the zIIP had the zIIP been running in MT=1 instead of MT=2. But remember it's an estimate and based on numbers that change based on the instruction mix. Doing accurate capacity planning with estimates that vary this way is difficult. Which may not be a problem if your capacity planning for zIIPs is "when we start seeing cross-over to the GCPs we buy more zIIPs" (which is not necessarily a bad policy). SMT is a useful tool in certain situations, but IMHO, I wouldn't consider enabling MT=2 as the default. If you're having a problem that more zIIP capacity might help, then more real zIIP capacity is the best answer. In cases where that's impractical, MT=2 might be useful. Scott Chapman -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
Re: zIIP MultiThreads
We see 1.3 on peak hours. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
Re: zIIP MultiThreads
On 9/4/2020 9:15 AM, Michael Babcock wrote: Anyone using their zIIPs with the multithread parm in IEAOPTxx? Is that per LPAR or per zIIP? Meaning if I enable it in one LPAR is it enabled on all LPARs? What are the ramifications of enabling it and does it provide much benefit? Like all parmlib members, IEAOPTxx is processed one LPAR at a time. The benefit of two threads is better overall utilization of the zIIP core, but with slower per-thread speed (~70% instead of 100%). IMHO, if you need additional zIIP capacity for a production workload, it probably makes more sense to configure another zIIP core online than it does to enable MT=2. -- Phoenix Software International Edward E. Jaffe 831 Parkview Drive North El Segundo, CA 90245 https://www.phoenixsoftware.com/ This e-mail message, including any attachments, appended messages and the information contained therein, is for the sole use of the intended recipient(s). If you are not an intended recipient or have otherwise received this email message in error, any use, dissemination, distribution, review, storage or copying of this e-mail message and the information contained therein is strictly prohibited. If you are not an intended recipient, please contact the sender by reply e-mail and destroy all copies of this email message and do not otherwise utilize or retain this email message or any or all of the information contained therein. Although this email message and any attachments or appended messages are believed to be free of any virus or other defect that might affect any computer system into which it is received and opened, it is the responsibility of the recipient to ensure that it is virus free and no responsibility is accepted by the sender for any loss or damage arising in any way from its opening or use. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
Re: zIIP MultiThreads
1) Yes 2) Per LPAR 3) See above 4) It depends. Mark Jacobs Sent from ProtonMail, Swiss-based encrypted email. GPG Public Key - https://api.protonmail.ch/pks/lookup?op=get&search=markjac...@protonmail.com ‐‐‐ Original Message ‐‐‐ On Friday, September 4, 2020 12:15 PM, Michael Babcock wrote: > Anyone using their zIIPs with the multithread parm in IEAOPTxx? Is that > per LPAR or per zIIP? Meaning if I enable it in one LPAR is it enabled on > all LPARs? > > What are the ramifications of enabling it and does it provide much benefit? > > -- > > Michael Babcock > OneMain Financial > z/OS Systems Programmer, Lead > > > > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
zIIP MultiThreads
Anyone using their zIIPs with the multithread parm in IEAOPTxx? Is that per LPAR or per zIIP? Meaning if I enable it in one LPAR is it enabled on all LPARs? What are the ramifications of enabling it and does it provide much benefit? -- Michael Babcock OneMain Financial z/OS Systems Programmer, Lead -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
