On Thu, Jun 11, 2015 at 09:34:30AM -0700, Andi Kleen wrote: > On Thu, Jun 11, 2015 at 04:15:48PM +0200, Peter Zijlstra wrote: > > On Tue, Jun 09, 2015 at 05:21:10PM +0300, Adrian Hunter wrote: > > > Tracepoints are no good at all for non-privileged users > > > because they need either CAP_SYS_ADMIN or > > > /proc/sys/kernel/perf_event_paranoid <= -1. > > > > > > On the other hand, kernel software events need either > > > CAP_SYS_ADMIN or /proc/sys/kernel/perf_event_paranoid <= 1. > > > > So while I think it makes sense to allow some tracepoint outside of that > > priv level, IOW have a per tracepoint priv level filter thingy, I don't > > think sched_switch() is one of those because it explicitly exposes > > timing information on other tasks. > > It's trivial for a running program to measure when it gets context switched > by looking at timing. I don't think this event provides anything new over > that.
The _existing_ ones expose timing of _other_ tasks, the proposed one does not. -- 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/
