Hi Vince et al, On 12/05/2014 04:41 PM, Vince Weaver wrote: > Hello > > The PAPI developers recently ran into some issues with the various virtual > machine related settings in the perf_event_open() system call. > > What follows is what my proposed updated manpage sections look like; I'm > hoping to get some sort of feedback about the correctness of these statements.
Vince, thanks for the proposed patches. Does anyone have feedback about the correctness of Vince's proposed patches? > > exclude_hv > If this bit is set, the count excludes events that happen in > the hypervisor. This is mainly for PMUs that have > built-in hardware support for this feature (such as POWER; > this setting is silently ignored on x86). > > ... > > exclude_host (since Linux 3.2) > When conducting measurements that include processes > running VM instances (i.e. have executed a KVM_RUN > ioctl(2) ) only measure events happening inside a guest > instance. This is only meaningful outside the guests; > this setting does not change counts gathered inside of a > guest. Currently this functionality is x86 only. > > exclude_guest (since Linux 3.2) > When conducting measurements that include processes > running VM instances (i.e. have executed a KVM_RUN > ioctl(2) ) do not measure events happening inside guest > instances. This is only meaningful outside the guests; > this setting does not change counts gathered inside of a > guest. Currently this functionality is x86 only. > > > > Signed-off-by: Vince Weaver <[email protected]> > > diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2 > index 638124c..a413c13 100644 > --- a/man2/perf_event_open.2 > +++ b/man2/perf_event_open.2 > @@ -833,10 +833,9 @@ If this bit is set, the count excludes events that > happen in kernel-space. > .IR "exclude_hv" > If this bit is set, the count excludes events that happen in the > hypervisor. > -This is mainly for PMUs that have built-in support for handling this > -(such as POWER). > -Extra support is needed for handling hypervisor measurements on most > -machines. > +This is mainly for PMUs that have built-in hardware support > +for this feature (such as POWER; this setting is silently > +ignored on x86). > .TP > .IR "exclude_idle" > If set, don't count when the CPU is idle. > @@ -978,10 +977,24 @@ struct sample_id { > .fi > .TP > .IR "exclude_host" " (since Linux 3.2)" > -Do not measure time spent in VM host. > +When conducting measurements that include processes running > +VM instances (i.e. have executed a > +.I KVM_RUN > +.BR ioctl (2) > +) only measure events happening inside a guest instance. > +This is only meaningful outside the guests; this setting does > +not change counts gathered inside of a guest. > +Currently this functionality is x86 only. > .TP > .IR "exclude_guest" " (since Linux 3.2)" > -Do not measure time spent in VM guest. > +When conducting measurements that include processes running > +VM instances (i.e. have executed a > +.I KVM_RUN > +.BR ioctl (2) > +) do not measure events happening inside guest instances. > +This is only meaningful outside the guests; this setting does > +not change counts gathered inside of a guest. > +Currently this functionality is x86 only. > .TP > .IR "exclude_callchain_kernel" " (since Linux 3.7)" > Do not include kernel callchains. Thanks, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
