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authorEric Dumazet <eric.dumazet@gmail.com>2011-02-23 10:56:17 +0000
committerDavid S. Miller <davem@davemloft.net>2011-02-23 14:05:11 -0800
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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 <eric.dumazet@gmail.com> CC: Juliusz Chroboczek <Juliusz.Chroboczek@pps.jussieu.fr> CC: Stephen Hemminger <shemminger@vyatta.com> CC: Patrick McHardy <kaber@trash.net> CC: Andi Kleen <andi@firstfloor.org> CC: John W. Linville <linville@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/Kconfig')
-rw-r--r--net/sched/Kconfig11
1 files changed, 11 insertions, 0 deletions
diff --git a/net/sched/Kconfig b/net/sched/Kconfig
index 8c19b6e3201e..a7a5583d4f68 100644
--- a/net/sched/Kconfig
+++ b/net/sched/Kconfig
@@ -126,6 +126,17 @@ config NET_SCH_RED
To compile this code as a module, choose M here: the
module will be called sch_red.
+config NET_SCH_SFB
+ tristate "Stochastic Fair Blue (SFB)"
+ ---help---
+ Say Y here if you want to use the Stochastic Fair Blue (SFB)
+ packet scheduling algorithm.
+
+ See the top of <file:net/sched/sch_sfb.c> for more details.
+
+ To compile this code as a module, choose M here: the
+ module will be called sch_sfb.
+
config NET_SCH_SFQ
tristate "Stochastic Fairness Queueing (SFQ)"
---help---