On Tue, 2015-09-08 at 13:29 +0200, Peter Zijlstra wrote: > On Tue, Sep 08, 2015 at 07:07:55PM +1000, Michael Ellerman wrote: > > 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? > > Yeah, I've had it queued for a few days, there was one s390 compile > fail reported by the build-bot, which I've just fixed. So if nothing > weird happens, it should hit tip somewhere this week. Great, thanks. Now Sukadev can focus on getting the JSON events support merged, hopefully it won't require another 16 versions. cheers -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
