On Mon, Jul 21, 2014 at 11:47:35AM +0300, Adrian Hunter wrote: SNIP
> >>> If PERF_RECORD_FINISHED_ROUND is missing the queue will > >> > >> Why is it missing? > > > > it's stored only for tracepoints now patch 17 fixies that > > Wouldn't that make a huge difference all by itself? > > I would make that the first patch, and measure the difference > that it makes by itself. yes, that makes the difference.. still I think it's good to control perf memory allocation and do not let it take gigabytes just because this event is missing > >> How do you know the results are still valid? Wouldn't it > >> be better to wait that extra 15% and know that the data has > >> been processed correctly? > > > > The HALF flush could cause the out of order message > > (which I get occasionaly anyway). Patch 19 allows > > Occasional out-of-order messages would be worth investigating > IMHO. Either there is a bug or there is some "interesting" > data being recorded. I've got it via 'perf timechart record -I' sometimes: [jolsa@ibm-x3650m4-01 perf]$ sudo ./perf timechart record -I ^C[ perf record: Woken up 337 times to write data ] [ perf record: Captured and wrote 290.256 MB perf.data (~12681486 samples) ] Warning: Processed 3365931 events and lost 1 chunks! Check IO/CPU overload! [jolsa@ibm-x3650m4-01 perf]$ sudo ./perf report --stdio Timestamp below last timeslice flush 0x2276f58 [0x68]: failed to process type: 9 # To display the perf.data header info, please use --header/--header-only options. # I think the reaon might be that one of the CPU mmap buffer is behind and got data after the round finishes for its timestamp.. but I haven't checked deeply on this yet > > > out of order events after HALF flush. > > > > The main reason for me was to control the memory allocation, > > which could get enormous without ROUND events being stored. > > But now you are storing them... > > > The 100MB queue limit seems to be enough not to hit out of > > order event due to the HALF flush. > > ...so is the 100MB limit needed at all if you have ROUND > events? for data files captured without the ROUND events fix jirka -- 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/
