01 Mar, 2019
1 commit
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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
Signed-off-by: Leslie Monis
Signed-off-by: David S. Miller
27 Feb, 2019
2 commits
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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
Reported-by: Randy Dunlap
Tested-by: Randy Dunlap
Signed-off-by: David S. Miller -
Fix the incorrect reference link to RFC 8033
Signed-off-by: Leslie Monis
Signed-off-by: David S. Miller
26 Feb, 2019
7 commits
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RFC 8033 replaces the IETF draft for PIE
Signed-off-by: Mohit P. Tahiliani
Signed-off-by: Dhaval Khandla
Signed-off-by: Hrishikesh Hiraskar
Signed-off-by: Manish Kumar B
Signed-off-by: Sachin D. Patil
Signed-off-by: Leslie Monis
Acked-by: Dave Taht
Acked-by: Jamal Hadi Salim
Signed-off-by: David S. Miller -
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
Signed-off-by: Dhaval Khandla
Signed-off-by: Hrishikesh Hiraskar
Signed-off-by: Manish Kumar B
Signed-off-by: Sachin D. Patil
Signed-off-by: Leslie Monis
Acked-by: Dave Taht
Acked-by: Jamal Hadi Salim
Signed-off-by: David S. Miller -
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
Signed-off-by: Dhaval Khandla
Signed-off-by: Hrishikesh Hiraskar
Signed-off-by: Manish Kumar B
Signed-off-by: Sachin D. Patil
Signed-off-by: Leslie Monis
Acked-by: Dave Taht
Acked-by: Jamal Hadi Salim
Signed-off-by: David S. Miller -
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
Signed-off-by: Dhaval Khandla
Signed-off-by: Hrishikesh Hiraskar
Signed-off-by: Manish Kumar B
Signed-off-by: Sachin D. Patil
Signed-off-by: Leslie Monis
Acked-by: Dave Taht
Acked-by: Jamal Hadi Salim
Signed-off-by: David S. Miller -
RFC 8033 suggests a default value of 15 milliseconds for the
update interval.Signed-off-by: Mohit P. Tahiliani
Signed-off-by: Dhaval Khandla
Signed-off-by: Hrishikesh Hiraskar
Signed-off-by: Manish Kumar B
Signed-off-by: Sachin D. Patil
Signed-off-by: Leslie Monis
Acked-by: Dave Taht
Acked-by: Jamal Hadi Salim
Signed-off-by: David S. Miller -
RFC 8033 suggests a default value of 15 milliseconds for the
target queue delay.Signed-off-by: Mohit P. Tahiliani
Signed-off-by: Dhaval Khandla
Signed-off-by: Hrishikesh Hiraskar
Signed-off-by: Manish Kumar B
Signed-off-by: Sachin D. Patil
Signed-off-by: Leslie Monis
Acked-by: Dave Taht
Acked-by: Jamal Hadi Salim
Signed-off-by: David S. Miller -
RFC 8033 recommends a value of 16384 bytes for the queue
threshold.Signed-off-by: Mohit P. Tahiliani
Signed-off-by: Dhaval Khandla
Signed-off-by: Hrishikesh Hiraskar
Signed-off-by: Manish Kumar B
Signed-off-by: Sachin D. Patil
Signed-off-by: Leslie Monis
Acked-by: Dave Taht
Acked-by: Jamal Hadi Salim
Signed-off-by: David S. Miller
08 Oct, 2018
1 commit
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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
Signed-off-by: David S. Miller
22 Dec, 2017
2 commits
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This patch adds extack support for change callback for qdisc ops
structtur to prepare per-qdisc specific changes for extack.Cc: David Ahern
Acked-by: Jamal Hadi Salim
Signed-off-by: Alexander Aring
Signed-off-by: David S. Miller -
This patch adds extack support for init callback to prepare per-qdisc
specific changes for extack.Cc: David Ahern
Acked-by: Jamal Hadi Salim
Signed-off-by: Alexander Aring
Signed-off-by: David S. Miller
18 Oct, 2017
1 commit
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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
Cc: Cong Wang
Cc: Jiri Pirko
Cc: "David S. Miller"
Cc: netdev@vger.kernel.org
Signed-off-by: Kees Cook
Signed-off-by: David S. Miller
14 Apr, 2017
1 commit
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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
Signed-off-by: David S. Miller
19 Sep, 2016
2 commits
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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
Signed-off-by: David S. Miller -
Doesn't change generated code.
Signed-off-by: Florian Westphal
Signed-off-by: David S. Miller
26 Jun, 2016
1 commit
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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
Acked-by: Jesper Dangaard Brouer
Signed-off-by: David S. Miller
16 Jun, 2016
1 commit
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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
Signed-off-by: David S. Miller
01 Mar, 2016
1 commit
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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
Acked-by: Jamal Hadi Salim
Signed-off-by: Cong Wang
Signed-off-by: David S. Miller
30 Oct, 2014
1 commit
-
Cc: Vijay Subramanian
Cc: David S. Miller
Signed-off-by: Cong Wang
Acked-by: Eric Dumazet
30 Sep, 2014
1 commit
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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
Signed-off-by: David S. Miller
14 Feb, 2014
1 commit
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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
CC: Mythili Prabhu
CC: Norbert Kiesel
Signed-off-by: David S. Miller
15 Jan, 2014
1 commit
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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
Suggested-by: Hannes Frederic Sowa
Acked-by: Hannes Frederic Sowa
Signed-off-by: David S. Miller
07 Jan, 2014
1 commit
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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-00All 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
Signed-off-by: Mythili Prabhu
CC: Dave Taht
Signed-off-by: David S. Miller