Re: Large inlines in include/linux/skbuff.h

[Eric Dumazet <dada1@cosmosbay.com>]

Denis Vlasenko wrote:

>
>>
>>If this a specialized machine, with a small program that mostly uses
>>recv() & send() syscalls, then, inlining functions is a gain, since
>>icache may have a 100% hit ratio. Optimization guidelines are good for
>>the common cases, not every cases.
>>    
>>
>
>And if it is NOT a specialized machine? icache miss will nullify
>any speed advantages, while you still pay space penalty.
>We don't need to pay for at least ~250 kbytes wasted overall
>in allyesconfig kernel for each and every specialized
>setup conceivable, IMHO.
>  
>
The point is : if this IS a specialized machine, then the kernel is 
custom one, not allyesconfig.

This is imho what I do for specialized machines, and yes, I even inline 
some specific functions, like fget() and others.

But I didnt asked to not doing the un-inlining, I was just reminding 
that some guys (like me) are doing micro-optimizations that 'seem' to go 
against Optimizations guidelines from intel or AMD.

Eric