mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-16 16:54:20 +08:00
8af2a218de
Adaptative RED AQM for linux, based on paper from Sally FLoyd, Ramakrishna Gummadi, and Scott Shenker, August 2001 : http://icir.org/floyd/papers/adaptiveRed.pdf Goal of Adaptative RED is to make max_p a dynamic value between 1% and 50% to reach the target average queue : (max_th - min_th) / 2 Every 500 ms: if (avg > target and max_p <= 0.5) increase max_p : max_p += alpha; else if (avg < target and max_p >= 0.01) decrease max_p : max_p *= beta; target :[min_th + 0.4*(min_th - max_th), min_th + 0.6*(min_th - max_th)]. alpha : min(0.01, max_p / 4) beta : 0.9 max_P is a Q0.32 fixed point number (unsigned, with 32 bits mantissa) Changes against our RED implementation are : max_p is no longer a negative power of two (1/(2^Plog)), but a Q0.32 fixed point number, to allow full range described in Adatative paper. To deliver a random number, we now use a reciprocal divide (thats really a multiply), but this operation is done once per marked/droped packet when in RED_BETWEEN_TRESH window, so added cost (compared to previous AND operation) is near zero. dump operation gives current max_p value in a new TCA_RED_MAX_P attribute. Example on a 10Mbit link : tc qdisc add dev $DEV parent 1:1 handle 10: est 1sec 8sec red \ limit 400000 min 30000 max 90000 avpkt 1000 \ burst 55 ecn adaptative bandwidth 10Mbit # tc -s -d qdisc show dev eth3 ... qdisc red 10: parent 1:1 limit 400000b min 30000b max 90000b ecn adaptative ewma 5 max_p=0.113335 Scell_log 15 Sent 50414282 bytes 34504 pkt (dropped 35, overlimits 1392 requeues 0) rate 9749Kbit 831pps backlog 72056b 16p requeues 0 marked 1357 early 35 pdrop 0 other 0 Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
||
|---|---|---|
| .. | ||
| act_api.c | ||
| act_csum.c | ||
| act_gact.c | ||
| act_ipt.c | ||
| act_mirred.c | ||
| act_nat.c | ||
| act_pedit.c | ||
| act_police.c | ||
| act_simple.c | ||
| act_skbedit.c | ||
| cls_api.c | ||
| cls_basic.c | ||
| cls_cgroup.c | ||
| cls_flow.c | ||
| cls_fw.c | ||
| cls_route.c | ||
| cls_rsvp6.c | ||
| cls_rsvp.c | ||
| cls_rsvp.h | ||
| cls_tcindex.c | ||
| cls_u32.c | ||
| em_cmp.c | ||
| em_meta.c | ||
| em_nbyte.c | ||
| em_text.c | ||
| em_u32.c | ||
| ematch.c | ||
| Kconfig | ||
| Makefile | ||
| sch_api.c | ||
| sch_atm.c | ||
| sch_blackhole.c | ||
| sch_cbq.c | ||
| sch_choke.c | ||
| sch_drr.c | ||
| sch_dsmark.c | ||
| sch_fifo.c | ||
| sch_generic.c | ||
| sch_gred.c | ||
| sch_hfsc.c | ||
| sch_htb.c | ||
| sch_ingress.c | ||
| sch_mq.c | ||
| sch_mqprio.c | ||
| sch_multiq.c | ||
| sch_netem.c | ||
| sch_prio.c | ||
| sch_qfq.c | ||
| sch_red.c | ||
| sch_sfb.c | ||
| sch_sfq.c | ||
| sch_tbf.c | ||
| sch_teql.c | ||