> > Also of course it requires disabling/enabling PT explicitly for > > every perf message, which is slow. So you add at least 2*WRMSR cost > > (thousands of cycles). > > That's just dumb, no flush the entire PT buffer into a few large > records.
How would that work? You mean a separate buffer and then copy or map? ------ Also here are some more problems with interleaving: A common PT config is to just run it as a ring buffer in the background and only take the data out when something happens (sample, crash etc.) But the side band still needs to be logged and at arbitary times. So the PT wrapping will happen much more often than the perf wrapping. If you interleave you may actually end up with lots of small rings in a single buffer, unless you stop every time the buffer fills up (which would add a lot more overhead) I suppose it could be somehow parsed, but it would very different from what perf does today. -Andi -- a...@linux.intel.com -- Speaking for myself only. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
