(2013/12/20 17:20), Ingo Molnar wrote: > > * Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx> wrote: > >>> But a closer look indicates that the insertion of kprobes is >>> taking about three (!!) orders of magnitude longer than before, as >>> judged by the rate of increase of 'wc -l >>> /sys/kernel/debug/kprobes/list'. >> >> Right, because kprobes are not designed for thousands of probes. > > Then this needs to be fixed, because right now this bug is making it > near impossible to properly test kprobes robustness. > > For example a hash table (hashed by probe address) could be used in > addition to the list, to speed up basic operations. kprobe itself is already using hlist (6bits hash table). Maybe we'd better expand the table bits. However, the iteration of the list on debugfs is just doing seq_printf()s. I'm not exactly sure what Frank complaints about... I recommend Frank to use perf record and perf annotation to clarify which part caused that slow down. Thank you, -- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@xxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
