Re: interrupt latency and driver locking

From: Harti Brandt (brandt_at_fokus.fraunhofer.de)
Date: 09/22/03

  • Next message: Mark R. Weinstein: "BSD Versions -- Older" 
    Date: Mon, 22 Sep 2003 16:11:14 +0200 (CEST)
To: "M. Warner Losh" <imp@bsdimp.com>

    On Sat, 20 Sep 2003, M. Warner Losh wrote:

    MWL>In message: <XFMail.20030920142934.jdp@polstra.com>
    MWL> John Polstra <jdp@polstra.com> writes:
    MWL>: there will be no link changes except at bootstrap and shutdown.
    MWL>
    MWL>For server machines. For laptops, these events happen more often.
    MWL>However, for most laptops, the rate that they happen is typically on
    MWL>less than 1/hour. Still rare enough to not worry about optimizing it
    MWL>and your other points are good. I just wanted to make sure that it
    MWL>wasn't optimized to the point where disconnecting the cable from the
    MWL>laptop to move it accross the room, or another room doesn't cause huge
    MWL>problems.

    Perhaps the polling should be configurable., I struggled with this a year
    ago in the xl driver. I have an application that does real-time satellite
    simulation over two ethernet links with HZ=10000. This works really
    perfect (timing errors are not larger than 200usecs) except for the MII
    polling. With help from msilby we could cut down the mii polling delay
    from 8msecs to below 1msec. But, because that's still too much for my
    application, I have simply commented out the polling calls in the mii
    source. I suppose there are other application (servers) where one could
    simply switch them off. This could perhaps be done with a sysctl in
    mii(4).

    harti 

    -- 
harti brandt,
http://www.fokus.fraunhofer.de/research/cc/cats/employees/hartmut.brandt/private
brandt@fokus.fraunhofer.de, harti@freebsd.org
_______________________________________________
freebsd-arch@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-arch
To unsubscribe, send any mail to "freebsd-arch-unsubscribe@freebsd.org"
  • Next message: Mark R. Weinstein: "BSD Versions -- Older"