Re: zero-copy TCP

From: Alan Cox (
Date: Sat Sep 02 2000 - 16:35:11 EST

> to MANOS, and what a mess indeed. In NetWare, the only time data ever
> gets copied from incoming packets is:
> 1. A copy to userspace at a stream head.
> 2. An incoming write that gets copied into the file cache.

Sounds like Linux - one DMA and one copy to user space.

> Reads from cache are never copied. In fact, the network server locks a
> file cache page and sends it unaltered to the network drivers and DMA's
> directly from it. Since NetWare has WTD's these I/O requests get

Doesn't work with IP - you have to be able to checksum the data. For the
recent cards that can handle this have a look at TUX. The work is there ready
for 2.5


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This archive was generated by hypermail 2b29 : Thu Sep 07 2000 - 21:00:14 EST