Re: [Cake] GSO peel behaviour tweaks

[Sebastian Moeller <moeller0@gmx.de>]

Hi Kevin,

On Nov 24, 2015, at 10:12 , Kevin Darbyshire-Bryant <kevin@darbyshire-bryant.me.uk> wrote:

> I've just pushed 2 commits related to GSO peeling behaviour to master.
> 
> 1st tweak is at worst benign and at best removes a multiply compare for
> every packet enqueued.  I'd like to think the optimiser in the compiler
> would have done what I've done explicitly (in essence check this is a
> gso packet 1st before thinking about peeling it) but when I checked on
> x86_64 there was a definite difference in produced code.
> 
> 2nd tweak is *not* benign.  In essence this forces peeling if either ATM
> framing or packet overhead is specified.  Previously only ATM framing
> forced peeling.  I think this is more correct but unfortunately will be
> slower.

	Why? Does cake not account all the overhead that the de-composed aggregate will cause on the wire? If not, it should do that and keep the decision to peel or not-peel orthogonal, no?

Best Regards
	Sebastian

> 
> Commits can be reverted - feel free :-)
> 
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