On 10/18/2017 09:05 AM, Paolo Valente wrote: > >> Il giorno 18 ott 2017, alle ore 16:45, Jens Axboe <axboe@xxxxxxxxx> ha scritto: >> >> On 10/18/2017 07:19 AM, Tejun Heo wrote: >>>> We tried to understand the reason for this high overhead, and, in >>>> particular, to find out whether whether there was some issue that we >>>> could address on our own. But the causes seem somehow substantial: >>>> one of the most time-consuming operations needed by some blkg_*stats_* >>>> functions is, e.g., find_next_bit, for which we don't see any trivial >>>> replacement. >>> >>> Can you point to the specific ones? I can't find find_next_bit usages >>> in generic blkg code. >> >> Yeah, in general a report like this is pretty much useless without >> any sort of call traces or perf output. The best way to get help >> is to post exactly what to run to reproduce the performance issue, >> and profile output that shows/highlights the issues. >> > > Yes, sorry. To be very brief, I just provided a link to the script > with which one can immediately reproduce the issue. Brief is about number of words, you can never include too much actual information or data ;-) > I hope the information I have now provided in my reply to Tejun are> enough. The picture is no longer attached. What list was this on? -- Jens Axboe
