Re: [RFC] TCP Vegas for 2.6

[Andi Kleen <ak@suse.de>]

> +/* Vegas variables */
> +	struct {
> +		__u32	beg_snd_nxt;	/* right edge during last RTT */
> +		__u32	beg_snd_una;	/* left edge  during last RTT */
> +		__u32	beg_snd_cwnd;	/* saves the size of the cwnd */
> +		__u8	do_vegas;	/* do vegas for this connection */
> +		__u8	doing_vegas_now;/* if true, do vegas for this RTT */
> +		__u16	cntRTT;		/* # of RTTs measured within last RTT */
> +		__u32	minRTT;		/* min of RTTs measured within last RTT (in usec) */
> +		__u32	baseRTT;	/* the min of all Vegas RTT measurements seen (in usec) */
> +	} vegas;

How about making this and the experimental westwood stuff CONFIG_* 
options? At least for the data structures?  Or maybe alternatively allocating
it separately when needed only (this would avoid CONFIG_* options)

I remember when we made jokes about the size of TCBs of other stacks 
compared to Linux, but we must have exceeded them all by far. The additional
code is not really a problem, but adding all that bloat to dynamic data 
structures adds up quickly when you have a few thousands of them, limiting
scalability.

-Andi