On Wednesday, 04/19/2017 at 08:27 GMT, Victor Echavarry Diaz <vechava...@evertecinc.com> wrote: > We are having issues with Linux guests that show high cpu steal when the IFL's is not at full > capacity. > > Why this happening is system has IFL? How z/VM works with that? Some of the guest with high steal > are Top Users. A guest under cluster do fencing
I assert that users who consume a lot of CPU are more likely to notice that CPU time and wall clock time do not match. All virtualization platforms with shared CPU resources will have this issue. We're just better at measuring it. :-) I tell my clients: a) Stop running top. It wastes resources. b) If the application is running well, don't worry about it. c) Steal time doesn't tell you *why* the guest (or LPAR!) is not being dispatched, so you need to use z/VM performance data to find out why. d) If steal is steadily increasing, you might be adding workload faster than you are adding CPUs, or your LPAR weights are out of whack. Alan Altmark Senior Managing z/VM and Linux Consultant Lab Services System z Delivery Practice IBM Systems & Technology Group ibm.com/systems/services/labservices office: 607.429.3323 mobile; 607.321.7556 alan_altm...@us.ibm.com IBM Endicott ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
