On Tue, 2010-03-02 at 15:09 +0800, Zhang, Yanmin wrote: > With vanilla host kernel, perf top data is stable and spinlock doesn't take > too much cpu time. > With guest os, __ticket_spin_lock consumes 28% cpu time, and sometimes it > fluctuates between 9%~28%. > > Another interesting finding is aim7. If I start aim7 on tmpfs testing in > guest os with 1GB memory, > the login hangs and cpu is busy. With the new patch, I could check what > happens in guest os, where > spinlock is busy and kernel is shrinking memory mostly from slab.
Hehe, you've just discovered the reason for paravirt spinlocks ;-) But neat stuff, although I don't think you need PERF_SAMPLE_KVM, it should simply always report the guest sample if it came from the guest, you can extend PERF_RECORD_MISC_CPUMODE_MASK to add guest states. -- 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
