Re: High CPU usage with sata_nv

From: Lee Revell
Date: Wed Feb 21 2007 - 13:04:40 EST

On 2/21/07, Matthew Fredrickson <creslin@xxxxxxxxxx> wrote:
It's a 2.6.18 kernel. What we're seeing (by means of the interrupt pin
on another card) is extremely large interrupt latency (measured from
the time the interrupt pin goes low to the first couple lines of code
in the IRQ handler to clear it) occasionally, in the order of 500-700
microseconds. I figured it was some other driver on the system
disabling irqs for a long period of time, but it's difficult to trace
what might be doing that.

Apply the -rt kernel patch and enable the latency tracer, it will tell
you what code path is responsible.

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