Messages in this thread | | | Date | Thu, 5 Nov 2015 16:00:55 +0100 | Subject | Re: NETIF_F_GSO_SOFTWARE vs NETIF_F_GSO | From | "Jason A. Donenfeld" <> |
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Hi Herbert,
Thanks for your response!
On Thu, Nov 5, 2015 at 1:15 PM, Herbert Xu <herbert@gondor.apana.org.au> wrote: > The NETIF_F_GSO flag turns on software GSO which should be on > anyway. So that could be why it seems to make no difference.
GSO is on by default? That makes sense, okay.
> > NETIF_F_GSO_SOFTWARE is actually a collection of bits that lists > the protocols for which we support software GSO. The bits themselves > are in fact an indication that the hardware supports GSO directly. > So by turning them on you're electing to receive GSO packets > directly.
Right -- I saw the expansion in the header file -- it gets the various TSOs plus UFO. So what this means is that the packet hasn't yet been split up? So were I to add this option, then my driver would have to be responsible for splitting up the super-packets manually? In which case, there would be no performance benefit in using it, since GSO already does this just prior to ndo_start_xmit? Or would there be a performance benefit in receiving the super-packets and splitting them myself?
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