Date: Thu, 12 Mar 2009 15:40:36 -0700 (PDT) From: Barney Cordoba <barney_cordoba@yahoo.com> To: current@freebsd.org, Chris Ruiz <chris@young-alumni.com> Subject: Re: Interrupt routine usage not shown by top in 8.0 Message-ID: <87164.59627.qm@web63907.mail.re1.yahoo.com> In-Reply-To: <BCD14AB2-B275-420A-9AD5-278F1DFAD9AB@young-alumni.com>
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--- On Thu, 3/12/09, Chris Ruiz <chris@young-alumni.com> wrote:
> From: Chris Ruiz <chris@young-alumni.com>
> Subject: Re: Interrupt routine usage not shown by top in 8.0
> To: current@freebsd.org
> Date: Thursday, March 12, 2009, 5:17 PM
> On Mar 12, 2009, at 3:23 PM, Barney Cordoba wrote:
>
> >
> > I'm fireing 400Kpps at a udp blackhole port.
> I'm getting 6000
> > interrupts
> > per second on em3:
> >
> > testbox# vmstat -i; sleep 1; vmstat -i
> > interrupt total rate
> > irq1: atkbd0 1 0
> > irq6: fdc0 1 0
> > irq17: uhci1+ 2226 9
> > irq18: uhci2 ehci+ 9 0
> > cpu0: timer 470507 1993
> > irq256: em0 665 2
> > irq259: em3 1027684 4354
> > cpu1: timer 470272 1992
> > cpu3: timer 470273 1992
> > cpu2: timer 470273 1992
> > Total 2911911 12338
> >
> > interrupt total rate
> > irq1: atkbd0 1 0
> > irq6: fdc0 1 0
> > irq17: uhci1+ 2226 9
> > irq18: uhci2 ehci+ 9 0
> > cpu0: timer 472513 1993
> > irq256: em0 668 2
> > irq259: em3 1033703 4361
> > cpu1: timer 472278 1992
> > cpu3: timer 472279 1992
> > cpu2: timer 472279 1992
> > Total 2925957 12345
> >
> >
> > top -SH shows:
> >
> > PID STATE C TIME CPU COMMAND
> > 10 CPU3 3 7:32 100.00% idle
> > 10 CPU2 2 7:32 100.00% idle
> > 10 RUN 0 7:31 100.00% idle
> > 10 CPU1 1 7:31 100.00% idle
> >
> > This implies that CPU usage is substantially
> under-reported in general
> > by the system. Note that I've modified
> em_irq_fast() to call
> > em_handle_rxtx() directly rather than scheduling a
> task to illustrate
> > the problem
> >
> > Barney
>
> The version of top in the base system is known to provide
> incorrect
> metrics.
>
> Chris
Does that imply that there exists a version that provides correct
information?
Barney
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