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Date: Wed, 07 Oct 2009 13:46:27 +0500
From: rihad <rihad@mail.ru>
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To: Robert Watson <rwatson@FreeBSD.org>
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Cc: freebsd-net@freebsd.org, Eugene Grosbein <eugen@kuzbass.ru>,
	Luigi Rizzo <rizzo@iet.unipi.it>, Julian Elischer <julian@elischer.org>
Subject: Re: dummynet dropping too many packets
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Robert Watson wrote:
> 
> On Wed, 7 Oct 2009, Eugene Grosbein wrote:
> 
>> On Tue, Oct 06, 2009 at 08:28:35PM +0500, rihad wrote:
>>
>>> I don't think net.inet.ip.intr_queue_maxlen is relevant to this 
>>> problem, as net.inet.ip.intr_queue_drops is normally zero or very 
>>> close to it at all times.
>>
>> When net.isr.direct is 1, this queue is used very seldom. Would you 
>> change it to 0, it will be used extensively.
> 
> Just to clarify this more specifically:
> 
> With net.isr.direct set to 0, the netisr will always be used when 
> processing inbound IP packets.
> 
Maybe I've done something wrong, but setting net.isr.direct=0 on a live 
system hasn't yet overrun the default queue of 50 @460-470 mbit/s:
$ sysctl net.inet.ip | fgrep intr
net.inet.ip.intr_queue_maxlen: 50
net.inet.ip.intr_queue_drops: 0
$ sysctl net.isr.direct
net.isr.direct: 0


I've yet to test how this direct=0 improves extensive dummynet drops.