On Wed, 2009-03-18 at 23:19 -0500, Tom Zanussi wrote: > On Wed, 2009-03-18 at 16:07 +0100, Martin Peschke wrote > > This is my theory: > > Timing matters. It's a race caused by improper protection of critical > > sections in a producer-consumer scenario. A bug in the bookkeeping > > allows a reader to read at a position that is just being written to. > > > > It does look consistent with a reader reading an event that's been > reserved but not yet written, or partially written e.g. if an event > being written on one cpu was read by another before the first one > finished. So this is part of relay's design, and it's up to user space to make sure that reader and writer are on the same CPU? > Can you see if the below patch to blktrace userspace helps? It appears to fix it. I will give it more testing in a larger environment. > Or failing that, explicitly using gettid() in place of getpid() in > sched_setaffinity(). Or, failing that, you had mentioned previously > that you would try to reproduce the problem on your laptop - were you > able to do that? If so, it would help in debugging it further... This didn't work out. But then, it's a single-CPU machine. Thanks, Martin -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html