From e13e02a3c68d899169c78d9a18689bd73491d59a Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 23 Feb 2011 10:56:17 +0000 Subject: net_sched: SFB flow scheduler This is the Stochastic Fair Blue scheduler, based on work from : W. Feng, D. Kandlur, D. Saha, K. Shin. Blue: A New Class of Active Queue Management Algorithms. U. Michigan CSE-TR-387-99, April 1999. http://www.thefengs.com/wuchang/blue/CSE-TR-387-99.pdf This implementation is based on work done by Juliusz Chroboczek General SFB algorithm can be found in figure 14, page 15: B[l][n] : L x N array of bins (L levels, N bins per level) enqueue() Calculate hash function values h{0}, h{1}, .. h{L-1} Update bins at each level for i = 0 to L - 1 if (B[i][h{i}].qlen > bin_size) B[i][h{i}].p_mark += p_increment; else if (B[i][h{i}].qlen == 0) B[i][h{i}].p_mark -= p_decrement; p_min = min(B[0][h{0}].p_mark ... B[L-1][h{L-1}].p_mark); if (p_min == 1.0) ratelimit(); else mark/drop with probabilty p_min; I did the adaptation of Juliusz code to meet current kernel standards, and various changes to address previous comments : http://thread.gmane.org/gmane.linux.network/90225 http://thread.gmane.org/gmane.linux.network/90375 Default flow classifier is the rxhash introduced by RPS in 2.6.35, but we can use an external flow classifier if wanted. tc qdisc add dev $DEV parent 1:11 handle 11: \ est 0.5sec 2sec sfb limit 128 tc filter add dev $DEV protocol ip parent 11: handle 3 \ flow hash keys dst divisor 1024 Notes: 1) SFB default child qdisc is pfifo_fast. It can be changed by another qdisc but a child qdisc MUST not drop a packet previously queued. This is because SFB needs to handle a dequeued packet in order to maintain its virtual queue states. pfifo_head_drop or CHOKe should not be used. 2) ECN is enabled by default, unlike RED/CHOKe/GRED With help from Patrick McHardy & Andi Kleen Signed-off-by: Eric Dumazet CC: Juliusz Chroboczek CC: Stephen Hemminger CC: Patrick McHardy CC: Andi Kleen CC: John W. Linville Signed-off-by: David S. Miller --- net/sched/Makefile | 1 + 1 file changed, 1 insertion(+) (limited to 'net/sched/Makefile') diff --git a/net/sched/Makefile b/net/sched/Makefile index 06c6cdfd1948..2e77b8dba22e 100644 --- a/net/sched/Makefile +++ b/net/sched/Makefile @@ -24,6 +24,7 @@ obj-$(CONFIG_NET_SCH_RED) += sch_red.o obj-$(CONFIG_NET_SCH_GRED) += sch_gred.o obj-$(CONFIG_NET_SCH_INGRESS) += sch_ingress.o obj-$(CONFIG_NET_SCH_DSMARK) += sch_dsmark.o +obj-$(CONFIG_NET_SCH_SFB) += sch_sfb.o obj-$(CONFIG_NET_SCH_SFQ) += sch_sfq.o obj-$(CONFIG_NET_SCH_TBF) += sch_tbf.o obj-$(CONFIG_NET_SCH_TEQL) += sch_teql.o -- cgit v1.2.3