[ag-automation] Adding OSADL patch to 2.6.33.7 increases latency and CPU usage?

[Robert Schwebel]

On Wed, May 09, 2012 at 06:27:41PM -0500, Grant Edwards wrote:
> X is somewhere around 20. The really annoying thing is that the
> "thing" that requires its interrupt serviced so fast is a blob of IP
> in an FPGA. The blob asserts an IRQ line, and I have to toggle a bit
> in a register inside that same blob within 25us (5 of 25 is already
> allocated to another bit of intervening hardware). Why somebody
> couldn't spend a few gates and do that in the FPGA itself is beyond
> me. I can't mention who's responsible for that chumk of IP (sometimes
> I wonder if that's what NDA's are really for).

Well, it is an FPGA, so you could put a little state machine around your
IP core which does not much more than the servicing of the hot path.

rsc
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