Commit 3b585b34 authored Mar 14, 2011 by stephen hemminger Committed by David S. Miller Mar 14, 2011

tcp_cubic: enable high resolution ack time if needed



This is a refined version of an earlier patch by Lucas Nussbaum.
Cubic needs RTT values in milliseconds. If HZ < 1000 then
the values will be too coarse.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Reported-by: Lucas Nussbaum <lucas.nussbaum@loria.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 17a6e9f1

net/ipv4/tcp_cubic.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -459,6 +459,10 @@ static int __init cubictcp_register(void)
		/* divide by bic_scale and by constant Srtt (100ms) */
		do_div(cube_factor, bic_scale * 10);

		/* hystart needs ms clock resolution */
		if (hystart && HZ < 1000)
		cubictcp.flags \|= TCP_CONG_RTT_STAMP;

		return tcp_register_congestion_control(&cubictcp);
		}

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