Re: incorrect ping(8) interval with powerd(8)

From: Jeremie Le Hen (jeremie_at_le-hen.org)
Date: 06/16/05

  • Next message: Daniel Eriksson: "IPI_PREEMPTION, something to test for normal users?" 
    Date: Thu, 16 Jun 2005 09:57:43 +0200
To: "M. Warner Losh" <imp@bsdimp.com>

    > : May you delve into this a little bit more please ? The ping(8) manual
    > : page states that the -i flags makes ping(8) to wait a given couple of
    > : seconds. If I use the flags "-i 1", I expect ECHO Requests to be sent
    > : with one second between each, whatever the AC line status is.
    > : (Note that I didn't explicitely specified "-i 1" in the above example,
    > : but this doesn't change the behaviour.)
    >
    > Well, the rount trip times went way up (3x longer). That's normal for
    > a 200MHz CPU... My 333MHz EISA machine can't do much better than
    > that.
    >
    > But the 2.252s run time is a little longish. Do you see this
    > consistantly? If you ran it a second time would you get identical
    > results. I've seen ARP take a while... What else do you have running
    > on the system? Maybe a daemon that takes almost no time at 1.7GHz
    > takes a lot longer at 200Mhz and that's starving the ping process...
    > Or some driver has gone insane...

    Yes, I ran this test multiple times, and I almost get always this same
    result although I got 2.208s sometimes, but I don't think this is
    significant.

    FYI,
    my powerd(8) is configured to tastes AC-line four times per seconds.
    I tried reducing it's freqency from 4 to 1, but it doesn't change
    anything.

    ARP is not the culprit, the MAC address is already in cache.

    My kernel is compiled with INVARIANTS, but I don't have WITNESS. My
    network interface uses the bge(4) driver. No firewall rule or complex
    network setup.

    Anyway this doesn't hurt much. Thanks for lightening me.

    Best regards, 

    -- 
Jeremie Le Hen
< jeremie at le-hen dot org >< ttz at chchile dot org >
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