On Thu, 28 Aug 2008 09:38:31 +1000
Andrew Reilly <andr...@areilly.bpc-users.org> wrote:
On Wed, Aug 20, 2008 at 09:47:01PM -1000, Jeff Roberson wrote:
On Tue, 19 Aug 2008, Andrew Reilly wrote:
I haven't tried nice -20 because I don't want the priority to
drift or change, which is something that I thought the normal
levels did. I'll give it a go though, and report back.
With such a low cpu utilization I wouldn't expect it's the scheduling
algorithm. It may be a difference in preemption settings. Is preemption
enabled in both kernels?
I've just done a set of tests with setprio(... -20) vs
rtprio(...10), and with SCHED_ULE vs SCHED_4BSD. The results
are essentially as I reported before except that regular prio
-20 seems to be just as reliable as rtprio 10 under 4BSD and
just as unhelpful under _ULE.
For what it's worth, my audio buffering setup has a fragment
size of 0.7ms, but several buffers. How is device driver
activity prioritized? Does the scheduler in use effect how
device interrupts are handled, as well as user-land tasks?
I have kernels built with both schedulers sitting arround on
this machine now, so it's easy to switch back and forth if there
are some specific tests that I could do or other information
that I could provide.
Ah yes, but do you have options PREEMPTION set, which was Jeff's question?