Messages in this thread | | | Date | Mon, 18 Jan 2010 22:50:48 +0100 | From | Jarek Poplawski <> | Subject | Re: [PATCH] af_packet: Don't use skb after dev_queue_xmit() |
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On Mon, Jan 18, 2010 at 04:24:52PM -0500, Michael Breuer wrote: > On 1/18/2010 4:00 PM, Stephen Hemminger wrote: > >On Mon, 18 Jan 2010 15:56:45 -0500 > >Michael Breuer<mbreuer@majjas.com> wrote: > > > >>>>2. The dropped tx packet (DHCP) is a bit harder to recreate, but it > >>>>still happens. > >>>> > >You might want to use tc filter rule to set priority of DHCP packets > >higher. This would cause them to be in a separate queue and eliminate > >the problem. > > > Ok - for fun, tried that - no change. Not sure I see why this might > be a factor. The packet loss happens when TX load is low and RX > high. > Also, packets only being dropped if traversing a router vs.to the > router itself. Keep in mind that pings to the router did not lose > packets, pings through the router lost packets. The router was not > under load (traffic is being generated from a device connected via > the 1Gb switch, not the wifi router), and tcpdump on the router > input port shows the pings to the router, but not the ones through > the router. > > One added note, when I just tried this, the test data ended while > the packet loss was occurring. The DHCPOFFER packet loss did not > clear until about a minute after the throughput abated. I really > think something is getting hosed, and I'd but some weird interaction > with the arp logic high on the list of suspects. Not sure what else > would be a factor when looking at the extra hop on the same subnet.
Good point! Actually, IIRC, your setup might be a problem: you seem to have two switches on the path (I guess the router is a bridge for these wireless), so I wonder if it's not something between them.
Jarek P.
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