From d902e2c30aeba8d9d76d9c7845f4b9833f7c336d Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 15 Nov 2013 08:58:14 -0800 Subject: pkt_sched: fq: fix pacing for small frames MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [ Upstream commit f52ed89971adbe79b6438c459814034707b8ab91 ] For performance reasons, sch_fq tried hard to not setup timers for every sent packet, using a quantum based heuristic : A delay is setup only if the flow exhausted its credit. Problem is that application limited flows can refill their credit for every queued packet, and they can evade pacing. This problem can also be triggered when TCP flows use small MSS values, as TSO auto sizing builds packets that are smaller than the default fq quantum (3028 bytes) This patch adds a 40 ms delay to guard flow credit refill. Fixes: afe4fd062416 ("pkt_sched: fq: Fair Queue packet scheduler") Signed-off-by: Eric Dumazet Cc: Maciej Żenczykowski Cc: Willem de Bruijn Cc: Yuchung Cheng Cc: Neal Cardwell Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- include/uapi/linux/pkt_sched.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/uapi') diff --git a/include/uapi/linux/pkt_sched.h b/include/uapi/linux/pkt_sched.h index 83708f980786..66f925d3c07b 100644 --- a/include/uapi/linux/pkt_sched.h +++ b/include/uapi/linux/pkt_sched.h @@ -764,6 +764,9 @@ enum { TCA_FQ_FLOW_MAX_RATE, /* per flow max rate */ TCA_FQ_BUCKETS_LOG, /* log2(number of buckets) */ + + TCA_FQ_FLOW_REFILL_DELAY, /* flow credit refill delay in usec */ + __TCA_FQ_MAX }; -- cgit v1.2.3