Messages in this thread | | | Date | Tue, 11 Nov 2014 14:20:00 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v5 12/20] x86: perf: intel_pt: Intel PT PMU driver |
| |
On Tue, Nov 11, 2014 at 01:24:43PM +0200, Alexander Shishkin wrote: > Peter Zijlstra <peterz@infradead.org> writes:
> > Now I'm not sure we want to export all the bits you're using though. > > Like the topa_multiple_entires, that appears an implementation detail > > userspace should not really care about either way. > > Actually, userspace can make assumptions about lost data from this > bit.
Do explain; it feels entirely wrong to expose something like this, esp. since this crappy single TOPA thing is going away.
> But there are others, such as encoded address length. In future > there will also be several "caps" with allowed values for certain bit > fields in RTIT_CTL, such as timing packet frequencies.
No, those should not be caps, those should be in the format description.
| |