Re: packet re-ordering on SMP machines.
Ben Greear (firstname.lastname@example.org)
Sun, 25 Aug 2002 10:00:00 -0700
Alan Cox wrote:
> On Sun, 2002-08-25 at 08:18, Ben Greear wrote:
>>By re-ordered, I mean that a method called from process_backlog in dev.c
>>is being handed packets in a different order than they are being poked into
>>the driver with hard_start_xmit on the other interface. If each CPU can be running the
>>process_backlog, then I can see how this could be happening.
>>1) Is this expected behaviour?
>>2) Is there any standard (ie configurable) way to enforce strict ordering on an
>> SMP system?
>>3) If answer to 2 is no, would you all be interested in a patch that
>> did allow strict ordering (if indeed I can figure out how to write one)?
> You should never need it. Ethernet, hubs, switches, routers, internet
> backbones etc will all cause packet re-ordering. You should also expect
> the percentage of re-ordered frames on the net to rise and rise.
I would like to detect the number of pkts that such backbone hardware does
re-order, so if my end machine is also re-ordering, I cannot get valid
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Ben Greear <firstname.lastname@example.org> <Ben_Greear AT excite.com>
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