Subject: Re: [PATCH] Proportional Rate Reduction for TCP.

From: Andi Kleen <[email-masked]>
Date: Sat, 13 Aug 2011 22:05:25 -0700

Nandita Dukkipati <[email-masked]> writes:
> +
> +	if (tcp_packets_in_flight(tp) > tp->snd_ssthresh) {
> +		if (WARN_ON(!tp->prr_cwnd))
> +			tp->prr_cwnd = 1;
> +		sndcnt = DIV_ROUND_UP(tp->prr_delivered * tp->snd_ssthresh,
> +				      tp->prr_cwnd) - tp->prr_out;
> +	} else {
> +		sndcnt = min_t(int, delta,
> +			       max_t(int, tp->prr_delivered -
> tp->prr_out,

u32s here? This will likely do bad things with large enough windows.

The rest looks good to me as code, but I don't claim to fully understand the 
algorithm. Perhaps a sysctl to turn it off and a linux mib counter when 
it triggers would be useful in addition.

-Andi

-- 
[email-masked] -- Speaking for myself only