Jack O'Quin wrote:
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.

They already were mounted noatime :(

Con

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