On 07/21/2014 12:54 PM, Jiri Olsa wrote: > 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
I am not sure it should be the default then, if it is not needed going forward. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
