On Monday, 12/19/2016 at 10:21 GMT, Victor Echavarry Diaz <vechava...@evertecinc.com> wrote: > Can someone explain why CPU steal is? We believe that when the VM LPAR is using almost all is IFL's > CPU stealing begins between guests. But today this specific LPAR has 4 IFL and is using 350% and > one of the server, that has a one the highest share is having a steal of 70%.
"Steal" represents dispatch delay, as best as Linux can measure it. That is, Linux was ready to run, but z/VM couldn't run it. However, it isn't truly "stolen" time, as Linux has NO insight into WHY the dispatch delays are occurring. Examples of such delays include: - The z/VM LPAR is starved for cycles because of competition from other LPARs (weight) - Competition from other guests (share). I.e. "wait your turn" - The guest is in I/O wait - The guest is in page-wait - The guest is paused, waiting for DIAGNOSE or SERVC instruction (for example) to compelte 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/
