On Mon, Aug 05, 2013 at 03:36:32PM -0700, Christoffer Dall wrote: > 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 :) > Btw. you may want to take a look at this as well: http://academiccommons.columbia.edu/download/fedora_content/download/ac:162669/CONTENT/Dall_Nieh_2013_tech_report.pdf -Christoffer _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
