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2012-01-13net_sched: sfq: add optional RED on top of SFQEric Dumazet1-0/+20
Adds an optional Random Early Detection on each SFQ flow queue. Traditional SFQ limits count of packets, while RED permits to also control number of bytes per flow, and adds ECN capability as well. 1) We dont handle the idle time management in this RED implementation, since each 'new flow' begins with a null qavg. We really want to address backlogged flows. 2) if headdrop is selected, we try to ecn mark first packet instead of currently enqueued packet. This gives faster feedback for tcp flows compared to traditional RED [ marking the last packet in queue ] Example of use : tc qdisc add dev $DEV parent 1:1 handle 10: est 1sec 4sec sfq \ limit 3000 headdrop flows 512 divisor 16384 \ redflowlimit 100000 min 8000 max 60000 probability 0.20 ecn qdisc sfq 10: parent 1:1 limit 3000p quantum 1514b depth 127 headdrop flows 512/16384 divisor 16384 ewma 6 min 8000b max 60000b probability 0.2 ecn prob_mark 0 prob_mark_head 4876 prob_drop 6131 forced_mark 0 forced_mark_head 0 forced_drop 0 Sent 1175211782 bytes 777537 pkt (dropped 6131, overlimits 11007 requeues 0) rate 99483Kbit 8219pps backlog 689392b 456p requeues 0 In this test, with 64 netperf TCP_STREAM sessions, 50% using ECN enabled flows, we can see number of packets CE marked is smaller than number of drops (for non ECN flows) If same test is run, without RED, we can check backlog is much bigger. qdisc sfq 10: parent 1:1 limit 3000p quantum 1514b depth 127 headdrop flows 512/16384 divisor 16384 Sent 1148683617 bytes 795006 pkt (dropped 0, overlimits 0 requeues 0) rate 98429Kbit 8521pps backlog 1221290b 841p requeues 0 Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> CC: Stephen Hemminger <shemminger@vyatta.com> CC: Dave Taht <dave.taht@gmail.com> Tested-by: Dave Taht <dave.taht@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-01-05net_sched: sfq: extend limitsEric Dumazet1-9/+7
SFQ as implemented in Linux is very limited, with at most 127 flows and limit of 127 packets. [ So if 127 flows are active, we have one packet per flow ] This patch brings to SFQ following features to cope with modern needs. - Ability to specify a smaller per flow limit of inflight packets. (default value being at 127 packets) - Ability to have up to 65408 active flows (instead of 127) - Ability to have head drops instead of tail drops (to drop old packets from a flow) Example of use : No more than 20 packets per flow, max 8000 flows, max 20000 packets in SFQ qdisc, hash table of 65536 slots. tc qdisc add ... sfq \ flows 8000 \ depth 20 \ headdrop \ limit 20000 \ divisor 65536 Ram usage : 2 bytes per hash table entry (instead of previous 1 byte/entry) 32 bytes per flow on 64bit arches, instead of 384 for QFQ, so much better cache hit ratio. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> CC: Dave Taht <dave.taht@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-12-13netem: add cell concept to simulate special MAC behaviorHagen Paul Pfeifer1-0/+3
This extension can be used to simulate special link layer characteristics. Simulate because packet data is not modified, only the calculation base is changed to delay a packet based on the original packet size and artificial cell information. packet_overhead can be used to simulate a link layer header compression scheme (e.g. set packet_overhead to -20) or with a positive packet_overhead value an additional MAC header can be simulated. It is also possible to "replace" the 14 byte Ethernet header with something else. cell_size and cell_overhead can be used to simulate link layer schemes, based on cells, like some TDMA schemes. Another application area are MAC schemes using a link layer fragmentation with a (small) header each. Cell size is the maximum amount of data bytes within one cell. Cell overhead is an additional variable to change the per-cell-overhead (e.g. 5 byte header per fragment). Example (5 kbit/s, 20 byte per packet overhead, cell-size 100 byte, per cell overhead 5 byte): tc qdisc add dev eth0 root netem rate 5kbit 20 100 5 Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net> Signed-off-by: Florian Westphal <fw@strlen.de> Acked-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-12-09sch_red: generalize accurate MAX_P support to RED/GRED/CHOKEEric Dumazet1-0/+2
Now RED uses a Q0.32 number to store max_p (max probability), allow RED/GRED/CHOKE to use/report full resolution at config/dump time. Old tc binaries are non aware of new attributes, and still set/get Plog. New tc binary set/get both Plog and max_p for backward compatibility, they display "probability value" if they get max_p from new kernels. # tc -d qdisc show dev ... ... qdisc red 10: parent 1:1 limit 360Kb min 30Kb max 90Kb ecn ewma 5 probability 0.09 Scell_log 15 Make sure we avoid potential divides by 0 in reciprocal_value(), if (max_th - min_th) is big. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-12-09sch_red: Adaptative RED AQMEric Dumazet1-2/+4
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>
2011-12-01netem: rate extensionHagen Paul Pfeifer1-0/+5
Currently netem is not in the ability to emulate channel bandwidth. Only static delay (and optional random jitter) can be configured. To emulate the channel rate the token bucket filter (sch_tbf) can be used. But TBF has some major emulation flaws. The buffer (token bucket depth/rate) cannot be 0. Also the idea behind TBF is that the credit (token in buckets) fills if no packet is transmitted. So that there is always a "positive" credit for new packets. In real life this behavior contradicts the law of nature where nothing can travel faster as speed of light. E.g.: on an emulated 1000 byte/s link a small IPv4/TCP SYN packet with ~50 byte require ~0.05 seconds - not 0 seconds. Netem is an excellent place to implement a rate limiting feature: static delay is already implemented, tfifo already has time information and the user can skip TBF configuration completely. This patch implement rate feature which can be configured via tc. e.g: tc qdisc add dev eth0 root netem rate 10kbit To emulate a link of 5000byte/s and add an additional static delay of 10ms: tc qdisc add dev eth0 root netem delay 10ms rate 5KBps Note: similar to TBF the rate extension is bounded to the kernel timing system. Depending on the architecture timer granularity, higher rates (e.g. 10mbit/s and higher) tend to transmission bursts. Also note: further queues living in network adaptors; see ethtool(8). Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net> Acked-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@drr.davemloft.net>
2011-11-23tc: comment spelling fixesstephen hemminger1-3/+3
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-04-12Merge branch 'master' of ↵David S. Miller1-1/+1
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/net/smsc911x.c
2011-04-04pkt_sched: QFQ - quick fair queue schedulerstephen hemminger1-0/+15
This is an implementation of the Quick Fair Queue scheduler developed by Fabio Checconi. The same algorithm is already implemented in ipfw in FreeBSD. Fabio had an earlier version developed on Linux, I just cleaned it up. Thanks to Eric Dumazet for testing this under load. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-03-31Fix common misspellingsLucas De Marchi1-1/+1
Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-02-25netem: revised correlated loss generatorstephen hemminger1-0/+26
This is a patch originated with Stefano Salsano and Fabio Ludovici. It provides several alternative loss models for use with netem. This patch adds two state machine based loss models. See: http://netgroup.uniroma2.it/twiki/bin/view.cgi/Main/NetemCLG Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-02-25netem: define NETEM_DIST_MAXstephen hemminger1-0/+1
Rather than magic constant in code, expose the maximum size of packet distribution table in API. In iproute2, q_netem defines MAX_DIST as 16K already. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-02-24net_sched: SFB flow schedulerEric Dumazet1-0/+39
This is the Stochastic Fair Blue scheduler, based on work from : W. Feng, D. Kandlur, D. Saha, K. Shin. Blue: A New Class of Active Queue Management Algorithms. U. Michigan CSE-TR-387-99, April 1999. http://www.thefengs.com/wuchang/blue/CSE-TR-387-99.pdf This implementation is based on work done by Juliusz Chroboczek General SFB algorithm can be found in figure 14, page 15: B[l][n] : L x N array of bins (L levels, N bins per level) enqueue() Calculate hash function values h{0}, h{1}, .. h{L-1} Update bins at each level for i = 0 to L - 1 if (B[i][h{i}].qlen > bin_size) B[i][h{i}].p_mark += p_increment; else if (B[i][h{i}].qlen == 0) B[i][h{i}].p_mark -= p_decrement; p_min = min(B[0][h{0}].p_mark ... B[L-1][h{L-1}].p_mark); if (p_min == 1.0) ratelimit(); else mark/drop with probabilty p_min; I did the adaptation of Juliusz code to meet current kernel standards, and various changes to address previous comments : http://thread.gmane.org/gmane.linux.network/90225 http://thread.gmane.org/gmane.linux.network/90375 Default flow classifier is the rxhash introduced by RPS in 2.6.35, but we can use an external flow classifier if wanted. tc qdisc add dev $DEV parent 1:11 handle 11: \ est 0.5sec 2sec sfb limit 128 tc filter add dev $DEV protocol ip parent 11: handle 3 \ flow hash keys dst divisor 1024 Notes: 1) SFB default child qdisc is pfifo_fast. It can be changed by another qdisc but a child qdisc MUST not drop a packet previously queued. This is because SFB needs to handle a dequeued packet in order to maintain its virtual queue states. pfifo_head_drop or CHOKe should not be used. 2) ECN is enabled by default, unlike RED/CHOKe/GRED With help from Patrick McHardy & Andi Kleen Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> CC: Juliusz Chroboczek <Juliusz.Chroboczek@pps.jussieu.fr> CC: Stephen Hemminger <shemminger@vyatta.com> CC: Patrick McHardy <kaber@trash.net> CC: Andi Kleen <andi@firstfloor.org> CC: John W. Linville <linville@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-02-03sched: CHOKe flow schedulerstephen hemminger1-0/+29
CHOKe ("CHOose and Kill" or "CHOose and Keep") is an alternative packet scheduler based on the Random Exponential Drop (RED) algorithm. The core idea is: For every packet arrival: Calculate Qave if (Qave < minth) Queue the new packet else Select randomly a packet from the queue if (both packets from same flow) then Drop both the packets else if (Qave > maxth) Drop packet else Admit packet with proability p (same as RED) See also: Rong Pan, Balaji Prabhakar, Konstantinos Psounis, "CHOKe: a stateless active queue management scheme for approximating fair bandwidth allocation", Proceeding of INFOCOM'2000, March 2000. Help from: Eric Dumazet <eric.dumazet@gmail.com> Patrick McHardy <kaber@trash.net> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-01-20net_sched: implement a root container qdisc sch_mqprioJohn Fastabend1-0/+12
This implements a mqprio queueing discipline that by default creates a pfifo_fast qdisc per tx queue and provides the needed configuration interface. Using the mqprio qdisc the number of tcs currently in use along with the range of queues alloted to each class can be configured. By default skbs are mapped to traffic classes using the skb priority. This mapping is configurable. Configurable parameters, struct tc_mqprio_qopt { __u8 num_tc; __u8 prio_tc_map[TC_BITMASK + 1]; __u8 hw; __u16 count[TC_MAX_QUEUE]; __u16 offset[TC_MAX_QUEUE]; }; Here the count/offset pairing give the queue alignment and the prio_tc_map gives the mapping from skb->priority to tc. The hw bit determines if the hardware should configure the count and offset values. If the hardware bit is set then the operation will fail if the hardware does not implement the ndo_setup_tc operation. This is to avoid undetermined states where the hardware may or may not control the queue mapping. Also minimal bounds checking is done on the count/offset to verify a queue does not exceed num_tx_queues and that queue ranges do not overlap. Otherwise it is left to user policy or hardware configuration to create useful mappings. It is expected that hardware QOS schemes can be implemented by creating appropriate mappings of queues in ndo_tc_setup(). One expected use case is drivers will use the ndo_setup_tc to map queue ranges onto 802.1Q traffic classes. This provides a generic mechanism to map network traffic onto these traffic classes and removes the need for lower layer drivers to know specifics about traffic types. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-04net: cleanup include/linuxEric Dumazet1-74/+37
This cleanup patch puts struct/union/enum opening braces, in first line to ease grep games. struct something { becomes : struct something { Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-11pkt_sched: type should be __u32 in headerChuck Ebbert1-1/+1
Using u32 in this header breaks the build of iptables. Signed-off-by: Chuck Ebbert <cebbert@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-01-30headers_check fix: linux/pkt_sched.hJaswinder Singh Rajput1-0/+2
fix the following 'make headers_check' warning: usr/include/linux/pkt_sched.h:32: found __[us]{8,16,32,64} type without #include <linux/types.h> Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
2008-11-20pkt_sched: add DRR schedulerPatrick McHardy1-0/+16
Add classful DRR scheduler as a more flexible replacement for SFQ. The main difference to the algorithm described in "Efficient Fair Queueing using Deficit Round Robin" is that this implementation doesn't drop packets from the longest queue on overrun because its classful and limits are handled by each individual child qdisc. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-09-13pkt_sched: Add multiqueue scheduler supportAlexander Duyck1-0/+7
This patch is intended to add a qdisc to support the new tx multiqueue architecture by providing a band for each hardware queue. By doing this it is possible to support a different qdisc per physical hardware queue. This qdisc uses the skb->queue_mapping to select which band to place the traffic onto. It then uses a round robin w/ a check to see if the subqueue is stopped to determine which band to dequeue the packet from. Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-20net_sched: Add size table for qdiscsJussi Kivilinna1-0/+20
Add size table functions for qdiscs and calculate packet size in qdisc_enqueue(). Based on patch by Patrick McHardy http://marc.info/?l=linux-netdev&m=115201979221729&w=2 Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-18pkt_sched: Remove RR scheduler.David S. Miller1-9/+0
This actually fixes a bug added by the RR scheduler changes. The ->bands and ->prio2band parameters were being set outside of the sch_tree_lock() and thus could result in strange behavior and inconsistencies. It might be possible, in the new design (where there will be one qdisc per device TX queue) to allow similar functionality via a TX hash algorithm for RR but I really see no reason to export this aspect of how these multiqueue cards actually implement the scheduling of the the individual DMA TX rings and the single physical MAC/PHY port. Signed-off-by: David S. Miller <davem@davemloft.net>
2008-02-01[NET_SCHED]: sch_sfq: make internal queues visible as classesPatrick McHardy1-0/+5
Add support for dumping statistics and make internal queues visible as classes. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-29[NET_SCHED]: sch_api: introduce constant for rate table sizePatrick McHardy1-0/+2
Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-11[NET_SCHED]: Making rate table lookups more flexible.Jesper Dangaard Brouer1-2/+2
This is done in order to, add support to changing the rate table to use the upper-boundry L2T (length to time) value. Currently we use the lower-boundry, which result in under-estimating the actual bandwidth usage. Extend the tc_ratespec struct, with two parameters: 1) "cell_align" that allow adjusting the alignment of the rate table. 2) "overhead" that allow adding a packet overhead before the lookup. Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk> Acked-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-07-11[SCHED]: Qdisc changes and sch_rr added for multiqueuePeter P Waskiewicz Jr1-0/+9
Add the new sch_rr qdisc for multiqueue network device support. Allow sch_prio and sch_rr to be compiled with or without multiqueue hardware support. sch_rr is part of sch_prio, and is referenced from MODULE_ALIAS. This was done since sch_prio and sch_rr only differ in their dequeue routine. Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com> Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-04[PKT_SCHED] netem: packet corruption optionStephen Hemminger1-0/+7
Here is a new feature for netem in 2.6.16. It adds the ability to randomly corrupt packets with netem. A version was done by Hagen Paul Pfeifer, but I redid it to handle the cases of backwards compatibility with netlink interface and presence of hardware checksum offload. It is useful for testing hardware offload in devices. Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-06[PKT_SCHED]: (G)RED: Introduce hard droppingThomas Graf1-0/+2
Introduces a new flag TC_RED_HARDDROP which specifies that if ECN marking is enabled packets should still be dropped once the average queue length exceeds the maximum threshold. This _may_ help to avoid global synchronisation during small bursts of peers advertising but not caring about ECN. Use this option very carefully, it does more harm than good if (qth_max - qth_min) does not cover at least two average burst cycles. The difference to the current behaviour, in which we'd run into the hard queue limit, is that due to the low pass filter of RED short bursts are less likely to cause a global synchronisation. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2005-11-06[PKT_SCHED]: GRED: Support ECN markingThomas Graf1-2/+2
Adds a new u8 flags in a unused padding area of the netlink message. Adds ECN marking support to be used instead of dropping packets immediately. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2005-11-06[PKT_SCHED]: GRED: Cleanup and remove unnecessary codeThomas Graf1-26/+22
Removes unnecessary includes, initializers, and simplifies the code a bit. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2005-06-28[NETLINK]: Missing padding fields in dumped structuresPatrick McHardy1-3/+6
Plug holes with padding fields and initialized them to zero. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-05-26[PKT_SCHED] netem: allow random reordering (with fix)Stephen Hemminger1-1/+8
Here is a fixed up version of the reorder feature of netem. It is the same as the earlier patch plus with the bugfix from Julio merged in. Has expected backwards compatibility behaviour. Go ahead and merge this one, the TCP strangeness I was seeing was due to the reordering bug, and previous version of TSO patch. Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-04-17Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds1-0/+454
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!