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Date:      Tue, 09 Mar 2010 15:31:55 +0200
From:      Ian FREISLICH <ianf@clue.co.za>
To:        pyunyh@gmail.com
Cc:        current@freebsd.org
Subject:   Re: dev.bce.X.com_no_buffers increasing and packet loss 
Message-ID:  <E1NozXP-000GGH-T9@clue.co.za>
In-Reply-To: <20100308174949.GA1311@michelle.cdnetworks.com> 
References:  <20100308174949.GA1311@michelle.cdnetworks.com> <20100305215539.GG14818@michelle.cdnetworks.com> <20100305210435.GF14818@michelle.cdnetworks.com> <20100305184046.GD14818@michelle.cdnetworks.com> <20100305175639.GB14818@michelle.cdnetworks.com> <E1NnVaT-0003Ft-3p@clue.co.za> <E1Nnc4d-0003mB-6e@clue.co.za> <E1Nne0Q-0003uZ-OR@clue.co.za> <E1Nnesz-00040L-AQ@clue.co.za> <E1NoeCu-0006P9-12@clue.co.za> 

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Pyun YongHyeon wrote:
> On Mon, Mar 08, 2010 at 04:45:20PM +0200, Ian FREISLICH wrote:
> > Pyun YongHyeon wrote:
> > > On Fri, Mar 05, 2010 at 11:16:41PM +0200, Ian FREISLICH wrote:
> > > > Pyun YongHyeon wrote:
> > > > > Thanks for the info. Frankly, I have no idea how to explain the
> > > > > issue given that you have no heavy load.
> > > > 
> > > > How many cores would be involved in handling the traffic and runnig
> > > > PF rules on this machine?  There are 4x
> > > > CPU: Quad-Core AMD Opteron(tm) Processor 8354 (2194.51-MHz K8-class CPU
)
> > > > In this server.  I'm also using carp extensively.
> > > > 
> > > 
> > > pf(4) uses a single lock for processing, number of core would have
> > > no much benefit.
> > 
> > What's interesting is the effect on CPU utilisation and interrupt
> > generation that net.inet.ip.fastforwarding has:
> > 
> > net.inet.ip.fastforwarding=1
> > interrupt rate is around 10000/s per bce interface
> > cpu 8.0% interrupt
> > 
> 
> Yes, this is one of intentional change of the patch. Stock bce(4)
> seems to generate too much interrupts on BCM5709 so I rewrote
> interrupt handling with the help of David. sysctl nodes are also
> exported to control interrupt moderation so you can change them if
> you want. Default value was tuned to generate interrupts less than
> 10k per second and try to minimize latencies.

Can you explain the tunables please - I'm guessing it's these:

dev.bce.$i.tx_quick_cons_trip_int
dev.bce.$i.tx_quick_cons_trip
dev.bce.$i.tx_ticks_int
dev.bce.$i.tx_ticks
dev.bce.$i.rx_quick_cons_trip_int
dev.bce.$i.rx_quick_cons_trip
dev.bce.$i.rx_ticks_int
dev.bce.$i.rx_ticks


--
Ian Freislich



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