That is interesting. If the job single threads, then I'd say that a slow down is possible. It's called "the MP effect". Basically, in an SMP (Symmetric Multi Processing) environment, where each CPU has equal access to main memory, then you get an interference effect fighting for access to the shared memory. The more CPUs, the more interference. IBM tries to address this by having separate portions of memory be on separate memory busses. But I don't know how the z10's memory is laid out.
-- John McKown Systems Engineer IV IT Administrative Services Group HealthMarkets(r) 9151 Boulevard 26 * N. Richland Hills * TX 76010 (817) 255-3225 phone * john.mck...@healthmarkets.com * www.HealthMarkets.com Confidentiality Notice: This e-mail message may contain confidential or proprietary information. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. HealthMarkets(r) is the brand name for products underwritten and issued by the insurance subsidiaries of HealthMarkets, Inc. -The Chesapeake Life Insurance Company(r), Mid-West National Life Insurance Company of TennesseeSM and The MEGA Life and Health Insurance Company.SM > -----Original Message----- > From: IBM Mainframe Discussion List > [mailto:IBM-MAIN@bama.ua.edu] On Behalf Of gsg > Sent: Thursday, February 09, 2012 10:39 AM > To: IBM-MAIN@bama.ua.edu > Subject: Turning on additional CPs > > We have a z10 with 4 engines. Since upgrading to this box, > we were only running 3 engines. However, we recently turned > on the 4th engine. We noticed that several jobs started > running longer, which we didn't expect. Could turning on > additional engines actually make a job run longer? > Also, where can I find any read material on the affect of > turning on/off engines. > > > TIA > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@bama.ua.edu with the message: INFO IBM-MAIN > > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: INFO IBM-MAIN
