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? Thanks, -- Alex -- 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