>From 4d787557880a25967da7dfdb070eea8c6cf9c635 Mon Sep 17 00:00:00 2001 From: "Eric S. Raymond" Date: Wed, 13 Jun 2018 00:08:55 -0400 Subject: [PATCH 3/5] In tc-pie.8, fix up list and example syntax. Signed-off-by: Eric S. Raymond --- man/man8/tc-pie.8 | 56 ++++++++++++++++++++++++++++------------------- 1 file changed, 33 insertions(+), 23 deletions(-) diff --git a/man/man8/tc-pie.8 b/man/man8/tc-pie.8 index 278293bd..64192b86 100644 --- a/man/man8/tc-pie.8 +++ b/man/man8/tc-pie.8 @@ -27,10 +27,14 @@ int ] [ Proportional Integral controller-Enhanced (PIE) is a control theoretic active queue management scheme. It is based on the proportional integral controller but aims to control delay. The main design goals are - o Low latency control - o High link utilization - o Simple implementation - o Guaranteed stability and fast responsiveness +.IP +Low latency control +.IP +High link utilization +.IP +Simple implementation +.IP +Guaranteed stability and fast responsiveness .SH ALGORITHM PIE is designed to control delay effectively. First, an average dequeue rate is @@ -43,10 +47,11 @@ PIE makes adjustments to the probability based on the trend of the delay i.e. whether it is going up or down.The delay converges quickly to the target value specified. -alpha and beta are statically chosen parameters chosen to control the drop probability -growth and are determined through control theoretic approaches. alpha determines how -the deviation between the current and target latency changes probability. beta exerts -additional adjustments depending on the latency trend. +alpha and beta are statically chosen parameters chosen to control the +drop probability growth and are determined through control theoretic +approaches. alpha determines how the deviation between the current and +target latency changes probability. beta exerts additional adjustments +depending on the latency trend. The drop probabilty is used to mark packets in ecn mode. However, as in RED, beyond 10% packets are dropped based on this probability. The bytemode is used @@ -55,22 +60,24 @@ to drop packets proportional to the packet size. Additional details can be found in the paper cited below. .SH PARAMETERS -.SS limit +.TP +limit limit on the queue size in packets. Incoming packets are dropped when this limit is reached. Default is 1000 packets. - -.SS target +.TP +target is the expected queue delay. The default target delay is 20ms. - -.SS tupdate +.TP +tupdate is the frequency at which the system drop probability is calculated. The default is 30ms. - -.SS alpha -.SS beta +.TP +alpha +.TP +beta alpha and beta are parameters chosen to control the drop probability. These should be in the range between 0 and 32. - -.SS ecn | noecn +.TP +ecn | noecn is used to mark packets instead of dropping .B ecn to turn on ecn mode, @@ -78,8 +85,8 @@ to turn on ecn mode, to turn off ecn mode. By default, .B ecn is turned off. - -.SS bytemode | nobytemode +.TP +bytemode | nobytemode is used to scale drop probability proportional to packet size .B bytemode to turn on bytemode, @@ -89,6 +96,7 @@ to turn off bytemode. By default, is turned off. .SH EXAMPLES +.EX # tc qdisc add dev eth0 root pie # tc -s qdisc show qdisc pie 8034: dev eth0 root refcnt 2 limit 200p target 19000us tupdate 29000us alpha 2 beta 20 @@ -113,7 +121,7 @@ is turned off. backlog 33728b 32p requeues 0 prob 0.102262 delay 24000us avg_dq_rate 1464840 pkts_in 2468 overlimit 214 dropped 0 maxq 192 ecn_mark 71 - +.EE .SH SEE ALSO .BR tc (8), @@ -121,8 +129,10 @@ is turned off. .BR tc-red (8) .SH SOURCES - o IETF draft submission is at http://tools.ietf.org/html/draft-pan-tsvwg-pie-00 - o IEEE Conference on High Performance Switching and Routing 2013 : "PIE: A +.IP +IETF draft submission is at http://tools.ietf.org/html/draft-pan-tsvwg-pie-00 +.IP +IEEE Conference on High Performance Switching and Routing 2013 : "PIE: A Lightweight Control Scheme to Address the Bufferbloat Problem" .SH AUTHORS -- 2.17.1