On Sun, Aug 31, 2008 at 11:43 AM, Avi Kivity <[EMAIL PROTECTED]> wrote: > Running an idle Windows VM on Linux 2.6.26+ with kvm, one sees high values > for the kvm process in top (30%-70% cpu), where one would normally expect > 0%-1%. Surprisingly, the per-cpu system counters show almost 100% idle, > leading me to believe this is an accounting error and that the process does > not actually consume this much cpu.
Busted process accounting - This looks the same as http://bugzilla.kernel.org/show_bug.cgi?id=11209 . Please verify. Peter's patch in latest git stops showing "incorrect looking" CPU usage but at least the process times are still wrong, horribly. In fact the CPU usage thing in -rc5 is likely also incorrect but I need to analyze that bit a little more. >From Today's Git - PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 12961 parag 20 0 83000 8908 6628 R 0 0.1 5124415h npviewer.bin > > I bisected this to a scheduler change, namely > > commit 3e51f33fcc7f55e6df25d15b55ed10c8b4da84cd > Author: Peter Zijlstra <[EMAIL PROTECTED]> > Date: Sat May 3 18:29:28 2008 +0200 > > sched: add optional support for CONFIG_HAVE_UNSTABLE_SCHED_CLOCK > this replaces the rq->clock stuff (and possibly cpu_clock()). > - architectures that have an 'imperfect' hardware clock can set > CONFIG_HAVE_UNSTABLE_SCHED_CLOCK > - the 'jiffie' window might be superfulous when we update tick_gtod > before the __update_sched_clock() call in sched_clock_tick() > - cpu_clock() might be implemented as: > sched_clock_cpu(smp_processor_id()) > if the accuracy proves good enough - how far can TSC drift in a > single jiffie when considering the filtering and idle hooks? > [ [EMAIL PROTECTED]: various fixes and cleanups ] > Signed-off-by: Peter Zijlstra <[EMAIL PROTECTED]> > Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]> That patch sounds like it had open questions? Really giving this is a long standing bad regression, all the offending patches should be reverted in absence of a fix, no? Parag -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
