Alan: The Unix group are asking for this. Because they see the steal alert, they want to know what is this happen. Is there a red book or presentation that talk about this so the Unix group understand this?
Thanks, Victor Echavarry System Programmer Operating Systems EVERTEC, LLC -----Original Message----- From: Linux on 390 Port [mailto:[email protected]] On Behalf Of Alan Altmark Sent: Wednesday, April 19, 2017 5:48 PM To: [email protected] Subject: Re: High steal on z/linux guest On Wednesday, 04/19/2017 at 08:27 GMT, Victor Echavarry Diaz <[email protected]> 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 [email protected] IBM Endicott ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] 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/ WARNING: This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please delete it immediately. Please note that any views or opinions presented in this email are solely those of the author and do not necessarily represent those of EVERTEC, Inc. or its affiliates. Finally, the integrity and security of this message cannot be guaranteed on the Internet, and as such EVERTEC, Inc. and its affiliates accept no liability for any damage caused by any virus transmitted by this email. ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] 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/
