Messages in this thread | | | From | Roland Dreier <> | Subject | Re: [PATCH v2] tcp: splice as many packets as possible at once | Date | Wed, 04 Feb 2009 11:19:06 -0800 |
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> And the arbitrary choice of 9k for jumbo frames was total crap too. > It's clear that no hardware designer was involved in the process. > They have to stuff 16kB of RAM on a NIC to use only 9. And we need > to allocate 3 pages for slightly more than 2. 7.5 kB would have been > better in this regard.
9K was not totally arbitrary. The CRC used for checksumming ethernet packets has a probability of undetected errors that goes up about 11-thousand something bytes. So the real limit is ~11000 bytes, and I believe ~9000 was chosen to be able to carry 8K NFS payloads + all XDR and transport headers without fragmentation.
- R.
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