> > > The maps information is not critical for sampling. > > But is for correlating the addresses in those samples.
We still have the maps information for other threads in system. Only part of the information for some thread is lost. > > > > > If task_diag does not solve this problem, I think we still need a time > > out to force stop endless mmap processing. It's the simplest working > > solution so far. > > I disagree with the timeout. For example an overloaded system where > perf is not getting scheduled could trigger the same. It's not a perfect solution for all tools. But a working solution for perf. Without timeout, we get nothing from perf top/record. With timeout, we can do sampling. We can correlate the addresses in most samples. It's better than nothing. > > Also, in the spirit of perf if you are going to drop information you need to > generate an event that says information was lost and have the analysis > tools show a message that information was lost. You can't simply bail out > and have "[unknown]" shown for symbols / dsos. I get tons of user > comments about perf showing callchains properly; the proposed patch just > adds to that confusion. Currently, it will print a warning in perf top/record. I think I can do more and print warning in perf_session__warn_about_errors as Arnaldo suggested. Thanks, Kan > > David -- 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/
