Re: [patch] Real-Time Preemption, -RT-2.6.12-rc6-V0.7.48-00

From: William Weston
Date: Thu Jun 23 2005 - 17:24:04 EST

On Thu, 23 Jun 2005, Ingo Molnar wrote:

> yes, very likely hardware (or system BIOS, e.g. SMM) induced.

Running -50-17 on the Xeon/HT box, now with the ICH5 USB controller
disabled in BIOS.

The strangely regular ~200us idle jumps for both CPUs went away. Now I'm
seeing one CPU at a time disappear (often completely absent) in the
traces, with a the maximum wakeup generally hitting between 150us and
300us. While compiling a kernel and running vlc (which would skip frames
like mad, even with RR scheduling) I was able to get one trace of 2556us.

There's also BUG warnings for update_out_trace(). I'm not quite sure if
the trace behavior I'm seeing is related to this bug, but judging by the
behavior of vlc, I wouldn't bet on it.

Since the 2556us trace is quite large all the info is posted at:

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