On Mon, Aug 05, 2013 at 04:47:06PM -0400, Zhuoqun Cheng wrote: > Hi, > > I am not sure if this is the right place to ask this question. I read this > paper written by Antonios Motakis, Alexander Spyridakis, Daniel Raho about > performance analysis of KVM/ARM. > Link: > http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=1691977 > > I learned alot from this excellent paper. But one thing confuses me. In > section 4.1, PMU cycle counter is used to measure time cost of memory > allocation loop in guest's user mode. But in section 5.2, it is written > that "... because the performance counters are not accessible from a guest > running under KVM-on-ARM". > > So, I am wondering if it is possible to use PMU cycle counter in guest, > both kernel mode and user mode? I tried to use kernel module to enable user > mode access to cycle counter in host and it worked. But it seems that guest > kernel I am using doesn't support kernel module (I am using this one: > http://www.virtualopensystems.com/media/arndale/guest-zImage). I tried to > add a syscall to enable user mode access but failed either (got illegal > instruction error when programming counter in user mode). > > Can anyone give me any instruction or pointer on this? Thanks very much! > We don't have a clear picture on how we're going to support guest perf support as of yet. Patches are welcome :) -Christoffer _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
