summaryrefslogtreecommitdiff
path: root/net/sched/sch_codel.c
AgeCommit message (Collapse)Author
2017-04-13netlink: pass extended ACK struct to parsing functionsJohannes Berg
Pass the new extended ACK reporting struct to all of the generic netlink parsing functions. For now, pass NULL in almost all callers (except for some in the core.) Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-19sched: replace __skb_dequeue with __qdisc_dequeue_headFlorian Westphal
After previous patch these functions are identical. Replace __skb_dequeue in qdiscs with __qdisc_dequeue_head. Next patch will then make __qdisc_dequeue_head handle single-linked list instead of strcut sk_buff_head argument. Doesn't change generated code. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-25net_sched: drop packets after root qdisc lock is releasedEric Dumazet
Qdisc performance suffers when packets are dropped at enqueue() time because drops (kfree_skb()) are done while qdisc lock is held, delaying a dequeue() draining the queue. Nominal throughput can be reduced by 50 % when this happens, at a time we would like the dequeue() to proceed as fast as possible. Even FQ is vulnerable to this problem, while one of FQ goals was to provide some flow isolation. This patch adds a 'struct sk_buff **to_free' parameter to all qdisc->enqueue(), and in qdisc_drop() helper. I measured a performance increase of up to 12 %, but this patch is a prereq so that future batches in enqueue() can fly. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-15net_sched: sch_codel: defer skb freeing in codel_change()Eric Dumazet
codel_change() can use rtnl_qdisc_drop() to defer expensive skb freeing after locks are released. codel_reset() already has support for deferred skb freeing because it uses qdisc_reset_queue() Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-25codel: split into multiple filesMichal Kazior
It was impossible to include codel.h for the purpose of having access to codel_params or codel_vars structure definitions and using them for embedding in other more complex structures. This splits allows codel.h itself to be treated like any other header file while codel_qdisc.h and codel_impl.h contain function definitions with logic that was previously in codel.h. This copies over copyrights and doesn't involve code changes other than adding a few additional include directives to net/sched/sch*codel.c. Signed-off-by: Michal Kazior <michal.kazior@tieto.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-25codel: generalize the implementationMichal Kazior
This strips out qdisc specific bits from the code and makes it slightly more reusable. Codel will be used by wireless/mac80211 in the future. Signed-off-by: Michal Kazior <michal.kazior@tieto.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-29net_sched: update hierarchical backlog tooWANG Cong
When the bottom qdisc decides to, for example, drop some packet, it calls qdisc_tree_decrease_qlen() to update the queue length for all its ancestors, we need to update the backlog too to keep the stats on root qdisc accurate. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-05-13Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Four minor merge conflicts: 1) qca_spi.c renamed the local variable used for the SPI device from spi_device to spi, meanwhile the spi_set_drvdata() call got moved further up in the probe function. 2) Two changes were both adding new members to codel params structure, and thus we had overlapping changes to the initializer function. 3) 'net' was making a fix to sk_release_kernel() which is completely removed in 'net-next'. 4) In net_namespace.c, the rtnl_net_fill() call for GET operations had the command value fixed, meanwhile 'net-next' adjusted the argument signature a bit. This also matches example merge resolutions posted by Stephen Rothwell over the past two days. Signed-off-by: David S. Miller <davem@davemloft.net>
2015-05-10codel: add ce_threshold attributeEric Dumazet
For DCTCP or similar ECN based deployments on fabrics with shallow buffers, hosts are responsible for a good part of the buffering. This patch adds an optional ce_threshold to codel & fq_codel qdiscs, so that DCTCP can have feedback from queuing in the host. A DCTCP enabled egress port simply have a queue occupancy threshold above which ECT packets get CE mark. In codel language this translates to a sojourn time, so that one doesn't have to worry about bytes or bandwidth but delays. This makes the host an active participant in the health of the whole network. This also helps experimenting DCTCP in a setup without DCTCP compliant fabric. On following example, ce_threshold is set to 1ms, and we can see from 'ldelay xxx us' that TCP is not trying to go around the 5ms codel target. Queue has more capacity to absorb inelastic bursts (say from UDP traffic), as queues are maintained to an optimal level. lpaa23:~# ./tc -s -d qd sh dev eth1 qdisc mq 1: dev eth1 root Sent 87910654696 bytes 58065331 pkt (dropped 0, overlimits 0 requeues 42961) backlog 3108242b 364p requeues 42961 qdisc codel 8063: dev eth1 parent 1:1 limit 1000p target 5.0ms ce_threshold 1.0ms interval 100.0ms Sent 7363778701 bytes 4863809 pkt (dropped 0, overlimits 0 requeues 5503) rate 2348Mbit 193919pps backlog 255866b 46p requeues 5503 count 0 lastcount 0 ldelay 1.0ms drop_next 0us maxpacket 68130 ecn_mark 0 drop_overlimit 0 ce_mark 72384 qdisc codel 8064: dev eth1 parent 1:2 limit 1000p target 5.0ms ce_threshold 1.0ms interval 100.0ms Sent 7636486190 bytes 5043942 pkt (dropped 0, overlimits 0 requeues 5186) rate 2319Mbit 191538pps backlog 207418b 64p requeues 5186 count 0 lastcount 0 ldelay 694us drop_next 0us maxpacket 68130 ecn_mark 0 drop_overlimit 0 ce_mark 69873 qdisc codel 8065: dev eth1 parent 1:3 limit 1000p target 5.0ms ce_threshold 1.0ms interval 100.0ms Sent 11569360142 bytes 7641602 pkt (dropped 0, overlimits 0 requeues 5554) rate 3041Mbit 251096pps backlog 210446b 59p requeues 5554 count 0 lastcount 0 ldelay 889us drop_next 0us maxpacket 68130 ecn_mark 0 drop_overlimit 0 ce_mark 37780 ... Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Florian Westphal <fw@strlen.de> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Glenn Judd <glenn.judd@morganstanley.com> Cc: Nandita Dukkipati <nanditad@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Yuchung Cheng <ycheng@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-05-03codel: fix maxpacket/mtu confusionEric Dumazet
Under presence of TSO/GSO/GRO packets, codel at low rates can be quite useless. In following example, not a single packet was ever dropped, while average delay in codel queue is ~100 ms ! qdisc codel 0: parent 1:12 limit 16000p target 5.0ms interval 100.0ms Sent 134376498 bytes 88797 pkt (dropped 0, overlimits 0 requeues 0) backlog 13626b 3p requeues 0 count 0 lastcount 0 ldelay 96.9ms drop_next 0us maxpacket 9084 ecn_mark 0 drop_overlimit 0 This comes from a confusion of what should be the minimal backlog. It is pretty clear it is not 64KB or whatever max GSO packet ever reached the qdisc. codel intent was to use MTU of the device. After the fix, we finally drop some packets, and rtt/cwnd of my single TCP flow are meeting our expectations. qdisc codel 0: parent 1:12 limit 16000p target 5.0ms interval 100.0ms Sent 102798497 bytes 67912 pkt (dropped 1365, overlimits 0 requeues 0) backlog 6056b 3p requeues 0 count 1 lastcount 1 ldelay 36.3ms drop_next 0us maxpacket 10598 ecn_mark 0 drop_overlimit 0 Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Kathleen Nichols <nichols@pollere.com> Cc: Dave Taht <dave.taht@gmail.com> Cc: Van Jacobson <vanj@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-30net: sched: implement qstat helper routinesJohn Fastabend
This adds helpers to manipulate qstats logic and replaces locations that touch the counters directly. This simplifies future patches to push qstats onto per cpu counters. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-16fq_codel: should use qdisc backlog as thresholdEric Dumazet
codel_should_drop() logic allows a packet being not dropped if queue size is under max packet size. In fq_codel, we have two possible backlogs : The qdisc global one, and the flow local one. The meaningful one for codel_should_drop() should be the global backlog, not the per flow one, so that thin flows can have a non zero drop/mark probability. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Dave Taht <dave.taht@bufferbloat.net> Cc: Kathleen Nichols <nichols@pollere.com> Cc: Van Jacobson <van@pollere.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-14net/codel: Add missing #include <linux/prefetch.h>Geert Uytterhoeven
m68k allmodconfig: net/sched/sch_codel.c: In function ‘dequeue’: net/sched/sch_codel.c:70: error: implicit declaration of function ‘prefetch’ make[1]: *** [net/sched/sch_codel.o] Error 1 Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-10codel: Controlled Delay AQMEric Dumazet
An implementation of CoDel AQM, from Kathleen Nichols and Van Jacobson. http://queue.acm.org/detail.cfm?id=2209336 This AQM main input is no longer queue size in bytes or packets, but the delay packets stay in (FIFO) queue. As we don't have infinite memory, we still can drop packets in enqueue() in case of massive load, but mean of CoDel is to drop packets in dequeue(), using a control law based on two simple parameters : target : target sojourn time (default 5ms) interval : width of moving time window (default 100ms) Based on initial work from Dave Taht. Refactored to help future codel inclusion as a plugin for other linux qdisc (FQ_CODEL, ...), like RED. include/net/codel.h contains codel algorithm as close as possible than Kathleen reference. net/sched/sch_codel.c contains the linux qdisc specific glue. Separate structures permit a memory efficient implementation of fq_codel (to be sent as a separate work) : Each flow has its own struct codel_vars. timestamps are taken at enqueue() time with 1024 ns precision, allowing a range of 2199 seconds in queue, and 100Gb links support. iproute2 uses usec as base unit. Selected packets are dropped, unless ECN is enabled and packets can get ECN mark instead. Tested from 2Mb to 10Gb speeds with no particular problems, on ixgbe and tg3 drivers (BQL enabled). Usage: tc qdisc ... codel [ limit PACKETS ] [ target TIME ] [ interval TIME ] [ ecn ] qdisc codel 10: parent 1:1 limit 2000p target 3.0ms interval 60.0ms ecn Sent 13347099587 bytes 8815805 pkt (dropped 0, overlimits 0 requeues 0) rate 202365Kbit 16708pps backlog 113550b 75p requeues 0 count 116 lastcount 98 ldelay 4.3ms dropping drop_next 816us maxpacket 1514 ecn_mark 84399 drop_overlimit 0 CoDel must be seen as a base module, and should be used keeping in mind there is still a FIFO queue. So a typical setup will probably need a hierarchy of several qdiscs and packet classifiers to be able to meet whatever constraints a user might have. One possible example would be to use fq_codel, which combines Fair Queueing and CoDel, in replacement of sfq / sfq_red. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Dave Taht <dave.taht@bufferbloat.net> Cc: Kathleen Nichols <nichols@pollere.com> Cc: Van Jacobson <van@pollere.net> Cc: Tom Herbert <therbert@google.com> Cc: Matt Mathis <mattmathis@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>