* Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx> wrote: > tip-bot for Alexander Shishkin <tipbot@xxxxxxxxx> writes: > > > Commit-ID: ab92b232ae05c382c3df0e3d6a5c6d16b639ac8c > > Gitweb: http://git.kernel.org/tip/ab92b232ae05c382c3df0e3d6a5c6d16b639ac8c > > Author: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx> > > AuthorDate: Tue, 10 May 2016 16:18:32 +0300 > > Committer: Ingo Molnar <mingo@xxxxxxxxxx> > > CommitDate: Thu, 12 May 2016 14:45:59 +0200 > > > > perf/x86/intel/pt: Generate PMI in the STOP region as well > > > > Currently, the PT driver always sets the PMI bit one region (page) before > > the STOP region so that we can wake up the consumer before we run out of > > room in the buffer and have to disable the event. However, we also need > > an interrupt in the last output region, so that we actually get to disable > > the event (if no more room from new data is available at that point), > > otherwise hardware just quietly refuses to start, but the event is > > scheduled in and we end up losing trace data till the event gets removed. > > > > For a cpu-wide event it is even worse since there may not be any > > re-scheduling at all and no chance for the ring buffer code to notice > > that its buffer is filled up and the event needs to be disabled (so that > > the consumer can re-enable it when it finishes reading the data out). In > > other words, all the trace data will be lost after the buffer gets filled > > up. > > > > This patch makes PT also generate a PMI when the last output region is > > full. > > > > Reported-by: Markus Metzger <markus.t.metzger@xxxxxxxxx> > > Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx> > > Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> > > Cc: <stable@xxxxxxxxxxxxxxx> > > Can we also have this one queued up for stable 4.4 and 4.5? Agreed. Acked-by: Ingo Molnar <mingo@xxxxxxxxxx> Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html