Werner Almesberger <[EMAIL PROTECTED]> writes: > [ Cc:s trimmed, added abiss-general ] > > Con Kolivas wrote: >> Possibly reiserfs journal related. That has larger non-preemptible code >> sections. > > If I understand your workload right, it should consist mainly of > computation, networking (?), and disk reads.
The jack_test3.2 is basically a multiprocess realtime audio test. A fair amount of computation, signifcant task switch overhead, but most I/O is to the sound card. There's some disk activity starting clients and probably some other system activity in the background. > I don't know much about ReiserFS, but in some experiments with ext3, > using ABISS, we found that a reader application competing with best > effort readers would experience worst-case delays of dozens of > milliseconds. > > They were caused by journaled atime updates. Mounting the file > system with "noatime" reduced delays to a few hundred microseconds > (still worst-case). Interesting. Worth a try to verify. Con was seeing a 6msec delay every 20 seconds. This was devastating to the test, which tries to run a full realtime audio cycle every 1.45msec. -- joq - 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/
