On Thu, 2015-09-03 at 20:07 -0700, Sukadev Bhattiprolu wrote: > The 24x7 counters in Powerpc allow monitoring a large number of counters > simultaneously. They also allow reading several counters in a single > HCALL so we can get a more consistent snapshot of the system. > > Use the PMU's transaction interface to monitor and read several event > counters at once. The idea is that users can group several 24x7 events > into a single group of events. We use the following logic to submit > the group of events to the PMU and read the values: > > pmu->start_txn() // Initialize before first event > > for each event in group > pmu->read(event); // Queue each event to be read > > pmu->commit_txn() // Read/update all queuedcounters > > The ->commit_txn() also updates the event counts in the respective > perf_event objects. The perf subsystem can then directly get the > event counts from the perf_event and can avoid submitting a new > ->read() request to the PMU. > > Thanks to input from Peter Zijlstra. > > Signed-off-by: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx> > --- > arch/powerpc/perf/hv-24x7.c | 166 ++++++++++++++++++++++++++++++++++++++++++- This looks fine to me from an arch perspective. I assume the whole series can go via tip-something? Acked-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> cheers -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
