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 --- a/net/ipv4/tcp_cubic.c 2011-03-10 08:35:59.968882888 -0800 +++ b/net/ipv4/tcp_cubic.c 2011-03-10 08:36:10.241016524 -0800 @@ -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); } -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html