On 2011-02-08 10:15, Avi Kivity wrote: > On 02/07/2011 07:23 PM, Jan Kiszka wrote: >> On 2011-02-07 18:10, Avi Kivity wrote: >>> On 02/07/2011 06:59 PM, Jan Kiszka wrote: >>>>> >>>>> (well, actually, cpufreq_notifier and kvm_arch_hardware_enable are >>>>> already non preemptible, and the stats code should just go away?) >>>> >>>> The stats code is trivial to convert, so it doesn't matter. >>> >>> Removal is easier. >> >> Is that stat interface no longer used? > > It's there for compatibility. I'm itching to remove it. See > qemu-kvm.git/kvm/kvm_stat for the only known user, and for the > replacement via tracepoints. OK, but that will first take a grace period. > > Tracepoints have marginally lower overhead when disabled, and somewhat > higher overhead when enabled. A disadvantage of tracepoints is that it > is harder to associate an event with a vm when that event is triggered > by a workqueue, but I don't think it matters in practice (kvm_stat > doesn't even provide a per-vm breakdown). What about using the perf infrastructure for this? Besides that perf can reuse tracepoints, maybe there is even a more efficient way of added new stat sources. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
