aboutsummaryrefslogtreecommitdiffstats
path: root/net/sched/sch_pie.c (follow)
AgeCommit message (Collapse)AuthorFilesLines
2019-02-28net: sched: pie: avoid slow division in drop probability decayLeslie Monis1-1/+2
As per RFC 8033, it is sufficient for the drop probability decay factor to have a value of (1 - 1/64) instead of 98%. This avoids the need to do slow division. Suggested-by: David Laight <David.Laight@aculab.com> Signed-off-by: Leslie Monis <lesliemonis@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-26net: sched: pie: fix 64-bit divisionLeslie Monis1-1/+1
Use div_u64() to resolve build failures on 32-bit platforms. Fixes: 3f7ae5f3dc52 ("net: sched: pie: add more cases to auto-tune alpha and beta") Signed-off-by: Leslie Monis <lesliemonis@gmail.com> Reported-by: Randy Dunlap <rdunlap@infradead.org> Tested-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-26net: sched: pie: fix mistake in reference linkLeslie Monis1-1/+1
Fix the incorrect reference link to RFC 8033 Signed-off-by: Leslie Monis <lesliemonis@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-25net: sched: pie: update referencesMohit P. Tahiliani1-3/+1
RFC 8033 replaces the IETF draft for PIE Signed-off-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in> Signed-off-by: Dhaval Khandla <dhavaljkhandla26@gmail.com> Signed-off-by: Hrishikesh Hiraskar <hrishihiraskar@gmail.com> Signed-off-by: Manish Kumar B <bmanish15597@gmail.com> Signed-off-by: Sachin D. Patil <sdp.sachin@gmail.com> Signed-off-by: Leslie Monis <lesliemonis@gmail.com> Acked-by: Dave Taht <dave.taht@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-25net: sched: pie: add derandomization mechanismMohit P. Tahiliani1-1/+27
Random dropping of packets to achieve latency control may introduce outlier situations where packets are dropped too close to each other or too far from each other. This can cause the real drop percentage to temporarily deviate from the intended drop probability. In certain scenarios, such as a small number of simultaneous TCP flows, these deviations can cause significant deviations in link utilization and queuing latency. RFC 8033 suggests using a derandomization mechanism to avoid these deviations. Signed-off-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in> Signed-off-by: Dhaval Khandla <dhavaljkhandla26@gmail.com> Signed-off-by: Hrishikesh Hiraskar <hrishihiraskar@gmail.com> Signed-off-by: Manish Kumar B <bmanish15597@gmail.com> Signed-off-by: Sachin D. Patil <sdp.sachin@gmail.com> Signed-off-by: Leslie Monis <lesliemonis@gmail.com> Acked-by: Dave Taht <dave.taht@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-25net: sched: pie: add more cases to auto-tune alpha and betaMohit P. Tahiliani1-33/+32
The current implementation scales the local alpha and beta variables in the calculate_probability function by the same amount for all values of drop probability below 1%. RFC 8033 suggests using additional cases for auto-tuning alpha and beta when the drop probability is less than 1%. In order to add more auto-tuning cases, MAX_PROB must be scaled by u64 instead of u32 to prevent underflow when scaling the local alpha and beta variables in the calculate_probability function. Signed-off-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in> Signed-off-by: Dhaval Khandla <dhavaljkhandla26@gmail.com> Signed-off-by: Hrishikesh Hiraskar <hrishihiraskar@gmail.com> Signed-off-by: Manish Kumar B <bmanish15597@gmail.com> Signed-off-by: Sachin D. Patil <sdp.sachin@gmail.com> Signed-off-by: Leslie Monis <lesliemonis@gmail.com> Acked-by: Dave Taht <dave.taht@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-25net: sched: pie: change initial value of pie_vars->burst_timeMohit P. Tahiliani1-2/+2
RFC 8033 suggests an initial value of 150 milliseconds for the maximum time allowed for a burst of packets. Signed-off-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in> Signed-off-by: Dhaval Khandla <dhavaljkhandla26@gmail.com> Signed-off-by: Hrishikesh Hiraskar <hrishihiraskar@gmail.com> Signed-off-by: Manish Kumar B <bmanish15597@gmail.com> Signed-off-by: Sachin D. Patil <sdp.sachin@gmail.com> Signed-off-by: Leslie Monis <lesliemonis@gmail.com> Acked-by: Dave Taht <dave.taht@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-25net: sched: pie: change default value of pie_params->tupdateMohit P. Tahiliani1-1/+1
RFC 8033 suggests a default value of 15 milliseconds for the update interval. Signed-off-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in> Signed-off-by: Dhaval Khandla <dhavaljkhandla26@gmail.com> Signed-off-by: Hrishikesh Hiraskar <hrishihiraskar@gmail.com> Signed-off-by: Manish Kumar B <bmanish15597@gmail.com> Signed-off-by: Sachin D. Patil <sdp.sachin@gmail.com> Signed-off-by: Leslie Monis <lesliemonis@gmail.com> Acked-by: Dave Taht <dave.taht@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-25net: sched: pie: change default value of pie_params->targetMohit P. Tahiliani1-1/+1
RFC 8033 suggests a default value of 15 milliseconds for the target queue delay. Signed-off-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in> Signed-off-by: Dhaval Khandla <dhavaljkhandla26@gmail.com> Signed-off-by: Hrishikesh Hiraskar <hrishihiraskar@gmail.com> Signed-off-by: Manish Kumar B <bmanish15597@gmail.com> Signed-off-by: Sachin D. Patil <sdp.sachin@gmail.com> Signed-off-by: Leslie Monis <lesliemonis@gmail.com> Acked-by: Dave Taht <dave.taht@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-25net: sched: pie: change value of QUEUE_THRESHOLDMohit P. Tahiliani1-1/+1
RFC 8033 recommends a value of 16384 bytes for the queue threshold. Signed-off-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in> Signed-off-by: Dhaval Khandla <dhavaljkhandla26@gmail.com> Signed-off-by: Hrishikesh Hiraskar <hrishihiraskar@gmail.com> Signed-off-by: Manish Kumar B <bmanish15597@gmail.com> Signed-off-by: Sachin D. Patil <sdp.sachin@gmail.com> Signed-off-by: Leslie Monis <lesliemonis@gmail.com> Acked-by: Dave Taht <dave.taht@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-07net: sched: pie: fix coding style issuesLeslie Monis1-18/+18
Fix 5 warnings and 14 checks issued by checkpatch.pl: CHECK: Logical continuations should be on the previous line + if ((q->vars.qdelay < q->params.target / 2) + && (q->vars.prob < MAX_PROB / 5)) WARNING: line over 80 characters + q->params.tupdate = usecs_to_jiffies(nla_get_u32(tb[TCA_PIE_TUPDATE])); CHECK: Blank lines aren't necessary after an open brace '{' +{ + CHECK: braces {} should be used on all arms of this statement + if (qlen < QUEUE_THRESHOLD) [...] + else { [...] CHECK: Unbalanced braces around else statement + else { CHECK: No space is necessary after a cast + if (delta > (s32) (MAX_PROB / (100 / 2)) && CHECK: Unnecessary parentheses around 'qdelay == 0' + if ((qdelay == 0) && (qdelay_old == 0) && update_prob) CHECK: Unnecessary parentheses around 'qdelay_old == 0' + if ((qdelay == 0) && (qdelay_old == 0) && update_prob) CHECK: Unnecessary parentheses around 'q->vars.prob == 0' + if ((q->vars.qdelay < q->params.target / 2) && + (q->vars.qdelay_old < q->params.target / 2) && + (q->vars.prob == 0) && + (q->vars.avg_dq_rate > 0)) CHECK: Unnecessary parentheses around 'q->vars.avg_dq_rate > 0' + if ((q->vars.qdelay < q->params.target / 2) && + (q->vars.qdelay_old < q->params.target / 2) && + (q->vars.prob == 0) && + (q->vars.avg_dq_rate > 0)) CHECK: Blank lines aren't necessary before a close brace '}' + +} CHECK: Comparison to NULL could be written "!opts" + if (opts == NULL) CHECK: No space is necessary after a cast + ((u32) PSCHED_TICKS2NS(q->params.target)) / WARNING: line over 80 characters + nla_put_u32(skb, TCA_PIE_TUPDATE, jiffies_to_usecs(q->params.tupdate)) || CHECK: Blank lines aren't necessary before a close brace '}' + +} CHECK: No space is necessary after a cast + .delay = ((u32) PSCHED_TICKS2NS(q->vars.qdelay)) / WARNING: Missing a blank line after declarations + struct sk_buff *skb; + skb = qdisc_dequeue_head(sch); WARNING: Missing a blank line after declarations + struct pie_sched_data *q = qdisc_priv(sch); + qdisc_reset_queue(sch); WARNING: Missing a blank line after declarations + struct pie_sched_data *q = qdisc_priv(sch); + q->params.tupdate = 0; Signed-off-by: Leslie Monis <lesliemonis@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-21net: sched: sch: add extack for change qdisc opsAlexander Aring1-2/+3
This patch adds extack support for change callback for qdisc ops structtur to prepare per-qdisc specific changes for extack. Cc: David Ahern <dsahern@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Alexander Aring <aring@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-21net: sched: sch: add extack for init callbackAlexander Aring1-1/+2
This patch adds extack support for init callback to prepare per-qdisc specific changes for extack. Cc: David Ahern <dsahern@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Alexander Aring <aring@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-18net: sched: Convert timers to use timer_setup()Kees Cook1-4/+6
In preparation for unconditionally passing the struct timer_list pointer to all timer callbacks, switch to using the new timer_setup() and from_timer() to pass the timer pointer explicitly. Add pointer back to Qdisc. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: Jiri Pirko <jiri@resnulli.us> Cc: "David S. Miller" <davem@davemloft.net> Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-13netlink: pass extended ACK struct to parsing functionsJohannes Berg1-1/+1
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 Westphal1-1/+1
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>
2016-09-19pie: use qdisc_dequeue_head wrapperFlorian Westphal1-1/+1
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 Dumazet1-2/+3
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_pie: defer skb freeingEric Dumazet1-1/+1
pie_change() can use rtnl_qdisc_drop() to benefit from deferred freeing. pie_reset() is already using qdisc_reset_queue() Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-29net_sched: update hierarchical backlog tooWANG Cong1-2/+3
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>
2014-10-29sch_pie: schedule the timer after all init succeedWANG Cong1-1/+1
Cc: Vijay Subramanian <vijaynsu@cisco.com> Cc: David S. Miller <davem@davemloft.net> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: Eric Dumazet <edumazet@google.com>
2014-09-30net: sched: implement qstat helper routinesJohn Fastabend1-1/+1
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>
2014-02-13net: sched: Cleanup PIE commentsVijay Subramanian1-5/+16
Fix incorrect comment reported by Norbert Kiesel. Edit another comment to add more details. Also add references to algorithm (IETF draft and paper) to top of file. Signed-off-by: Vijay Subramanian <subramanian.vijay@gmail.com> CC: Mythili Prabhu <mysuryan@cisco.com> CC: Norbert Kiesel <nkiesel@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-01-14net: replace macros net_random and net_srandom with direct calls to prandomAruna-Hewapathirane1-1/+1
This patch removes the net_random and net_srandom macros and replaces them with direct calls to the prandom ones. As new commits only seem to use prandom_u32 there is no use to keep them around. This change makes it easier to grep for users of prandom_u32. Signed-off-by: Aruna-Hewapathirane <aruna.hewapathirane@gmail.com> Suggested-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-01-06net: pkt_sched: PIE AQM schemeVijay Subramanian1-0/+555
Proportional Integral controller Enhanced (PIE) is a scheduler to address the bufferbloat problem. >From the IETF draft below: " Bufferbloat is a phenomenon where excess buffers in the network cause high latency and jitter. As more and more interactive applications (e.g. voice over IP, real time video streaming and financial transactions) run in the Internet, high latency and jitter degrade application performance. There is a pressing need to design intelligent queue management schemes that can control latency and jitter; and hence provide desirable quality of service to users. We present here a lightweight design, PIE(Proportional Integral controller Enhanced) that can effectively control the average queueing latency to a target value. Simulation results, theoretical analysis and Linux testbed results have shown that PIE can ensure low latency and achieve high link utilization under various congestion situations. The design does not require per-packet timestamp, so it incurs very small overhead and is simple enough to implement in both hardware and software. " Many thanks to Dave Taht for extensive feedback, reviews, testing and suggestions. Thanks also to Stephen Hemminger and Eric Dumazet for reviews and suggestions. Naeem Khademi and Dave Taht independently contributed to ECN support. For more information, please see technical paper about PIE in the IEEE Conference on High Performance Switching and Routing 2013. A copy of the paper can be found at ftp://ftpeng.cisco.com/pie/. Please also refer to the IETF draft submission at http://tools.ietf.org/html/draft-pan-tsvwg-pie-00 All relevant code, documents and test scripts and results can be found at ftp://ftpeng.cisco.com/pie/. For problems with the iproute2/tc or Linux kernel code, please contact Vijay Subramanian (vijaynsu@cisco.com or subramanian.vijay@gmail.com) Mythili Prabhu (mysuryan@cisco.com) Signed-off-by: Vijay Subramanian <subramanian.vijay@gmail.com> Signed-off-by: Mythili Prabhu <mysuryan@cisco.com> CC: Dave Taht <dave.taht@bufferbloat.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.