[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-bugs] [Bug 882] Cpu Usage Discrepancies on Xen
http://bugzilla.xensource.com/bugzilla/show_bug.cgi?id=882 ------- Comment #1 from pradeep.vincent@xxxxxxxxx 2007-03-02 15:34 ------- Easy recreation method - 1. Allocate a virt and assign some decent weight (50% of the CPU or something like that). 2. Login to the virt, create deep enough directory structure using your favorite mechanism so that "ls -R /" takes a minimum of 50 secs to complete. 3. Reboot the physical box - Now we have a Xen3 node with atleast 1 virt. If you have other virts on the physical host (apart from the test virt), leave them idle so that we can get predictable/recreatable results. 4. Open 2 xterms, one for dom-0 and the other for the virt. Do a "su" or equivalent on the dom-0 xterm since "Xm" requires root access. 5. On dom-0 xterm, type "while true; do; /usr/sbin/xm list | grep <test virt slot>; sleep 10; done;" - Don't run it yet. 6. On test virt xterm, type "while true; do; grep cpu0 /proc/stat; sleep 10; done;" - Don't run it yet. 7. Make sure the above commands work fine on both the xterms (try it and then quit). 8. Open a 2nd xterm to the virt, change directory to root (cd /) and type "ls -R". Don't run the command yet. 9. Now, you have 3 xterms - 2 of them to monitor the cpu usage and 3rd one to start the workload. 10. At the same time, run the "while .." commands on xterms 1 and 2 (to monitor the cpu usage). After 10 secs, 2nd line will be printed out around the same time. 11. After the 2nd line is printed on BOTH the cpu usage monitoring xterms, go to the 3rd xterm and run "ls -R /" - Workload is running now. 12. Wait for the "ls -R /" to finish. After that wait for 1 more line to be printed on BOTH the cpu monitoring xterms. 13. The entire "ls -R /" 's CPU usage has been captured by both "xm" and /proc/stat. Any errors due to difference in startup and end times of cpu monitoring commands won't make a big impact to the end result. 14. Process the data from both the windows - I find differences between CPU usage as reported by /proc/stat inside the virt and cpu usage as reported by the hypervisor -- Configure bugmail: http://bugzilla.xensource.com/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug, or are watching the assignee. _______________________________________________ Xen-bugs mailing list Xen-bugs@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-bugs
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