Re: zero copy issue while receiving the data (counter part ofsendfil e)

[Mandeep Sandhu]

On Wed, 2004-12-22 at 01:13, Dmitry Yusupov wrote:
> indeed :)
> another words if you have modern NIC than you get "zero-copy"(except
> copy_to_user()) for free :)
what does "checksum on rx" mean??? Don't most of the NIC's support
DMA-ing to mem on rx-ing a packet? so what does "zero-copy for free"
mean here?

thanx,
-mandeep
> 
> Regards,
> Dima
> 
> On Tue, 2004-12-21 at 14:30 -0500, Jeff Garzik wrote:
> > Dmitry Yusupov wrote:
> > > Rajat,
> > > 
> > > small correction, if NIC supports DMA operation on receive, than no
> > > extra copy required. Therefore sock_recvmsg() and tcp_read_sock
> > 
> > large correction:  if NIC supports _checksum_ on receive, then no extra 
> > copy is required.
> > 
> > 	Jeff
> > 
> 
> 
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