From a0e0018c9a7ef5ce7f6d2c3ae16aecbbd16a8f67 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 4 May 2024 16:18:53 +0200 Subject: Adding upstream version 6.1.0. Signed-off-by: Daniel Baumann --- man/man8/tc-fq_codel.8 | 143 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 143 insertions(+) create mode 100644 man/man8/tc-fq_codel.8 (limited to 'man/man8/tc-fq_codel.8') diff --git a/man/man8/tc-fq_codel.8 b/man/man8/tc-fq_codel.8 new file mode 100644 index 0000000..7859063 --- /dev/null +++ b/man/man8/tc-fq_codel.8 @@ -0,0 +1,143 @@ +.TH FQ_CoDel 8 "4 June 2012" "iproute2" "Linux" +.SH NAME +CoDel \- Fair Queuing (FQ) with Controlled Delay (CoDel) +.SH SYNOPSIS +.B tc qdisc ... fq_codel +[ +.B limit +PACKETS ] [ +.B flows +NUMBER ] [ +.B target +TIME ] [ +.B interval +TIME ] [ +.B quantum +BYTES ] [ +.B ecn +| +.B noecn +] [ +.B ce_threshold +TIME ] [ +.B ce_threshold_selector +VALUE/MASK ] [ +.B memory_limit +BYTES ] + +.SH DESCRIPTION +FQ_Codel (Fair Queuing Controlled Delay) is queuing discipline that combines Fair +Queuing with the CoDel AQM scheme. FQ_Codel uses a stochastic model to classify +incoming packets into different flows and is used to provide a fair share of the +bandwidth to all the flows using the queue. Each such flow is managed by the +CoDel queuing discipline. Reordering within a flow is avoided since Codel +internally uses a FIFO queue. + +.SH PARAMETERS +.SS limit +has the same semantics as +.B codel +and is the hard limit on the real queue size. +When this limit is reached, incoming packets are dropped. Default is 10240 +packets. + +.SS memory_limit +sets a limit on the total number of bytes that can be queued in this FQ-CoDel +instance. The lower of the packet limit of the +.B limit +parameter and the memory limit will be enforced. Default is 32 MB. + + +.SS flows +is the number of flows into which the incoming packets are classified. Due to +the stochastic nature of hashing, multiple flows may end up being hashed into +the same slot. Newer flows have priority over older ones. This parameter can be +set only at load time since memory has to be allocated for the hash table. +Default value is 1024. + +.SS target +has the same semantics as +.B codel +and is the acceptable minimum +standing/persistent queue delay. This minimum delay is identified by tracking +the local minimum queue delay that packets experience. Default value is 5ms. + +.SS interval +has the same semantics as +.B codel +and is used to ensure that the measured minimum delay does not become too stale. +The minimum delay must be experienced in the last epoch of length +.BR interval . +It should be set on the order of the worst-case RTT through the bottleneck to +give endpoints sufficient time to react. Default value is 100ms. + +.SS quantum +is the number of bytes used as 'deficit' in the fair queuing algorithm. Default +is set to 1514 bytes which corresponds to the Ethernet MTU plus the hardware +header length of 14 bytes. + +.SS ecn | noecn +has the same semantics as +.B codel +and can be used to mark packets instead of dropping them. If +.B ecn +has been enabled, +.B noecn +can be used to turn it off and vice-a-versa. Unlike +.B codel, ecn +is turned on by default. + +.SS ce_threshold +sets a threshold above which all packets are marked with ECN Congestion +Experienced. This is useful for DCTCP-style congestion control algorithms that +require marking at very shallow queueing thresholds. + +.SS ce_threshold_selector +sets a filter so that the +.B ce_threshold +feature is applied to only a subset of the traffic seen by the qdisc. If set, the MASK value +will be applied as a bitwise AND to the diffserv/ECN byte of the IP header, and only if the +result of this masking equals VALUE, will the +.B ce_threshold +logic be applied to the packet. + +.SS drop_batch +sets the maximum number of packets to drop when +.B limit +or +.B memory_limit +is exceeded. Default value is 64. + +.SH EXAMPLES +#tc qdisc add dev eth0 root fq_codel +.br +#tc -s qdisc show +.br +qdisc fq_codel 8002: dev eth0 root refcnt 2 limit 10240p flows 1024 quantum 1514 + target 5.0ms interval 100.0ms ecn + Sent 428514 bytes 2269 pkt (dropped 0, overlimits 0 requeues 0) + backlog 0b 0p requeues 0 + maxpacket 256 drop_overlimit 0 new_flow_count 0 ecn_mark 0 + new_flows_len 0 old_flows_len 0 + +#tc qdisc add dev eth0 root fq_codel limit 2000 target 3ms interval 40ms noecn +.br +#tc -s qdisc show +.br +qdisc fq_codel 8003: dev eth0 root refcnt 2 limit 2000p flows 1024 quantum 1514 +target 3.0ms interval 40.0ms + Sent 2588985006 bytes 1783629 pkt (dropped 0, overlimits 0 requeues 34869) + backlog 0b 0p requeues 34869 + maxpacket 65226 drop_overlimit 0 new_flow_count 73 ecn_mark 0 + new_flows_len 1 old_flows_len 3 + + +.SH SEE ALSO +.BR tc (8), +.BR tc-codel (8), +.BR tc-red (8) + +.SH AUTHORS +FQ_CoDel was implemented by Eric Dumazet. This manpage was written +by Vijay Subramanian. Please report corrections to the Linux Networking +mailing list . -- cgit v1.2.3