On Wed, May 28, 2014 at 09:59:37AM +0200, Peter Zijlstra wrote: > On Wed, May 28, 2014 at 02:18:08PM +0800, Yan, Zheng wrote: > > When a fixed period is specified, this patch make perf use the PEBS > > auto reload mechanism. This makes normal profiling faster, because > > it avoids one costly MSR write in the PMI handler. > > > > You can't do this unconditionally. Like I think you mention in the next > patch, we need the PMI to fix up lots of cases.
There are two cases: (1) Fixed period specified with PEBS. The PMI still runs with threshold=1, but we can use the PEBS auto-reload mechanism to automatically rewrite the counter which is faster. (2) Free running mode with more constraints This is case (1) -andi -- a...@linux.intel.com -- Speaking for myself only -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
