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commit 8a22b9996b001c88f2bfb54c6de6a05fc39e177a Author: Jeremy Fitzhardinge <jeremy.fitzhardinge> Date: Mon Jul 12 11:49:59 2010 -0700 xen: drop xen_sched_clock in favour of using plain wallclock time This upstream patch was found while doing analysis for bug 709856. While it's unclear that this patch will resolve any other issues (now that we've already implemented a fix bug 709856). We should backport it and give it some good testing, as it may.
This request was evaluated by Red Hat Product Management for inclusion in a Red Hat Enterprise Linux maintenance release. Product Management has requested further review of this request by Red Hat Engineering, for potential inclusion in a Red Hat Enterprise Linux Update release for currently deployed products. This request is not yet committed for inclusion in an Update release.
Created attachment 504445 [details] [RHEL6.2 PATCH] xen: drop xen_sched_clock in favour of using plain wallclock time
A bit of history about this patch http://comments.gmane.org/gmane.comp.emulators.xen.devel/86173
Patch(es) available on kernel-2.6.32-160.el6
Created attachment 521811 [details] script to reproduce the defect Verified with kernel-2.6.32-193.el6. Reproduced the defect with the script provided in http://comments.gmane.org/gmane.comp.emulators.xen.devel/86173 with minor update. Boot up RHEL6.1 GA x86_64 PV guest with 4 vcpus (host processor : Intel Xeon E7- 4850), and ran the attached script, it got large value of user or sys， like: # time perl test.pl [...] Files=300, Tests=900, 31 wallclock secs ( 2.25 usr 4.65 sys + 6148914822.77 cusr 12297829458.52 csys = 18446744288.19 CPU) Result: PASS real 0m31.337s user 0m0.001s sys 204963824m23.408s After update guest kernel to kernel-2.6.32-193.el6, ran the attached script for several times, the results looks reasonable: # time perl test.pl [...] Files=300, Tests=900, 32 wallclock secs ( 2.31 usr 4.55 sys + 7.14 cusr 29.03 csys = 43.03 CPU) Result: PASS real 0m32.446s user 0m9.985s sys 0m33.772s So change bug to VERIFIED.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. http://rhn.redhat.com/errata/RHSA-2011-1530.html