Re: decreasing interrupt CPU load

From: Uwe Doering (gemini_at_geminix.org)
Date: 10/20/04

  • Next message: Jason Stone: "Re: decreasing interrupt CPU load" 
    Date: Wed, 20 Oct 2004 22:16:40 +0200
To: freebsd-performance@freebsd.org

    Oleg Gawriloff wrote:
    > Hello, Eric!
    > You wrote to "Oleg Gawriloff" <barzog@telecom.by> on Wed, 20 Oct 2004
    > 08:08:32 -0500:
    >
    > EA> I've had really great performance with the em NICs, and bad experiences
    > EA> with bge's (the hardware is flaky).
    > OK, we'll try. Is there any problems with any of supported chipsets in
    > em-driver with polling? There many negative answer about polling support
    > in fxp on 82550, and good answers about 82558 and 82559 with fxp-driver.

    Since you mentioned earlier that you run this on an SMP system, are you
    aware that device polling is available only for single CPU kernels, that
    is, not in SMP mode? This is poorly documented, unfortunately. You can
    find out about it by looking at the first couple of lines of
    'sys/kern/kern_poll.c'.

    Depending on what else you do on this server you might be better off
    with running it in single CPU mode, with device polling enabled (kernel
    compiled with DEVICE_POLLING and HZ=1000). This could make a
    considerable difference with the fxp driver already. I suggest to try
    it out before you start making changes to the hardware.

        Uwe 

    -- 
Uwe Doering         |  EscapeBox - Managed On-Demand UNIX Servers
gemini@geminix.org  |  http://www.escapebox.net
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  • Next message: Jason Stone: "Re: decreasing interrupt CPU load"