Re: interrupt latency/700microsecs

Alan Cox (alan@lxorguk.ukuu.org.uk)
27 May 2002 19:53:46 +0100


On Mon, 2002-05-27 at 17:30, Muthal Sangam wrote:
> On kernel 2.4.7, AMDK6 @ 450MHz processor, is it possible to get latency
> fluctuations of upto 700microsecs for running the timer interrupt, due to
> interrupts being disabled ?
>
> I am using the time stamp counter and reading it at the start of the timer
> interrupt and measuring the cycles elapsed between two inovocations of it.
> The number of cycles elapsed is ~4500225, but sometimes it increases to as
> high as 4848032. Can i conclude that this difference is due to interrupts
> being disabled in critical sections ? ( I think i am making some mistake :-)

In X with a matrox G200 I've observed processor stalls in excess of 1mS
so Im not actually much suprised.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/