Re: PREEMPT_RT vs I-PIPE: the numbers, part 2

From: Paulo Marques
Date: Thu Jun 23 2005 - 09:50:27 EST

Kristian Benoit wrote:
Your analysis is correct, but with 600,000 samples, it is possible that
we got 2 peeks (perhaps not maximum), one on the logger and one on the
target. So in my point of view, the maximum value is probably somewhere
between 55us / 2 and 55us - 7us. And probably closer to 55us / 2.

I could provide some help here, by providing the schematics and firmware for having a microcontroller do the pulse timing part. The schematics should be extremely simple, and easy to build in a breadboard (no soldering required) with standard parts from electronics resellers.

With a hardware solution we could measure the *actual* target latency with sub-microsecond accuracy, and do some fun stuff too, like triggering the pulse at random intervals in a given range, etc.

The microcontroller would then connect to the logger (or the HOST in your setup, and avoid an extra computer) through a serial port to report the measurements.

Is this something that could be useful, or do you think this is just overkill?

Paulo Marques -

It is a mistake to think you can solve any major problems
just with potatoes.
Douglas Adams
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at