diff options
| author | Eric Dumazet <edumazet@google.com> | 2021-10-14 10:59:18 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-10-15 11:33:08 +0100 |
| commit | e72aeb9ee0e34c57dc90793d0bf82cab9624d64e (patch) | |
| tree | 7cbd2d668e45099e5eb4943bef211c211e8f9749 /include/net/codel.h | |
| parent | 70e939ddea7f014b94fe001db65c3efc986e4add (diff) | |
fq_codel: implement L4S style ce_threshold_ect1 marking
Add TCA_FQ_CODEL_CE_THRESHOLD_ECT1 boolean option to select Low Latency,
Low Loss, Scalable Throughput (L4S) style marking, along with ce_threshold.
If enabled, only packets with ECT(1) can be transformed to CE
if their sojourn time is above the ce_threshold.
Note that this new option does not change rules for codel law.
In particular, if TCA_FQ_CODEL_ECN is left enabled (this is
the default when fq_codel qdisc is created), ECT(0) packets can
still get CE if codel law (as governed by limit/target) decides so.
Section 4.3.b of current draft [1] states:
b. A scheduler with per-flow queues such as FQ-CoDel or FQ-PIE can
be used for L4S. For instance within each queue of an FQ-CoDel
system, as well as a CoDel AQM, there is typically also ECN
marking at an immediate (unsmoothed) shallow threshold to support
use in data centres (see Sec.5.2.7 of [RFC8290]). This can be
modified so that the shallow threshold is solely applied to
ECT(1) packets. Then if there is a flow of non-ECN or ECT(0)
packets in the per-flow-queue, the Classic AQM (e.g. CoDel) is
applied; while if there is a flow of ECT(1) packets in the queue,
the shallower (typically sub-millisecond) threshold is applied.
Tested:
tc qd replace dev eth1 root fq_codel ce_threshold_ect1 50usec
netperf ... -t TCP_STREAM -- K dctcp
tc -s -d qd sh dev eth1
qdisc fq_codel 8022: root refcnt 32 limit 10240p flows 1024 quantum 9212 target 5ms ce_threshold_ect1 49us interval 100ms memory_limit 32Mb ecn drop_batch 64
Sent 14388596616 bytes 9543449 pkt (dropped 0, overlimits 0 requeues 152013)
backlog 0b 0p requeues 152013
maxpacket 68130 drop_overlimit 0 new_flow_count 95678 ecn_mark 0 ce_mark 7639
new_flows_len 0 old_flows_len 0
[1] L4S current draft:
https://datatracker.ietf.org/doc/html/draft-ietf-tsvwg-l4s-arch
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Ingemar Johansson S <ingemar.s.johansson@ericsson.com>
Cc: Tom Henderson <tomh@tomh.org>
Cc: Bob Briscoe <in@bobbriscoe.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/codel.h')
| -rw-r--r-- | include/net/codel.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/net/codel.h b/include/net/codel.h index a6e428f80135..5e8b181b76b8 100644 --- a/include/net/codel.h +++ b/include/net/codel.h @@ -102,6 +102,7 @@ static inline u32 codel_time_to_us(codel_time_t val) * @interval: width of moving time window * @mtu: device mtu, or minimal queue backlog in bytes. * @ecn: is Explicit Congestion Notification enabled + * @ce_threshold_ect1: if ce_threshold only marks ECT(1) packets */ struct codel_params { codel_time_t target; @@ -109,6 +110,7 @@ struct codel_params { codel_time_t interval; u32 mtu; bool ecn; + bool ce_threshold_ect1; }; /** |