Date: Thu, 12 Mar 2009 18:12:49 -0500 From: Chris Ruiz <chris@young-alumni.com> To: freebsd-current@freebsd.org Subject: Re: Interrupt routine usage not shown by top in 8.0 Message-ID: <494612FF-EB15-467D-B11C-C46480D695C8@young-alumni.com> In-Reply-To: <87164.59627.qm@web63907.mail.re1.yahoo.com> References: <87164.59627.qm@web63907.mail.re1.yahoo.com>
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On Mar 12, 2009, at 5:40 PM, Barney Cordoba wrote: > --- 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 Edwin Groothuis was working on updating top to 3.8 late last year. If you search google for "Request for testing - top 3.8b1 in the base system" you can find a lot of discussion on the list regarding top. Chris
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