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12 commits

Author SHA1 Message Date
Randy Dunlap d1cca97454 pie: fix kernel-doc notation warning
Spell a struct member's name correctly to prevent a kernel-doc
warning.

pie.h:38: warning: Function parameter or member 'tupdate' not described in 'pie_params'

Fixes: b42a3d7c7c ("pie: improve comments and commenting style")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Leslie Monis <lesliemonis@gmail.com>
Cc: "Mohit P. Tahiliani" <tahiliani@nitk.edu.in>
Cc: Gautam Ramakrishnan <gautamramk@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Link: https://lore.kernel.org/r/20230714045127.18752-9-rdunlap@infradead.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-07-14 20:39:30 -07:00
Leslie Monis 5c5840e4b9 pie: realign comment
Realign a comment after the change introduced by the
previous patch.

Signed-off-by: Leslie Monis <lesliemonis@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-04 13:25:55 -08:00
Leslie Monis 105e808c1d pie: remove pie_vars->accu_prob_overflows
The variable pie_vars->accu_prob is used as an accumulator for
probability values. Since probabilty values are scaled using the
MAX_PROB macro denoting (2^64 - 1), pie_vars->accu_prob is
likely to overflow as it is of type u64.

The variable pie_vars->accu_prob_overflows counts the number of
times the variable pie_vars->accu_prob overflows.

The MAX_PROB macro needs to be equal to at least (2^39 - 1) in
order to do precise calculations without any underflow. Thus
MAX_PROB can be reduced to (2^56 - 1) without affecting the
precision in calculations drastically. Doing so will eliminate
the need for the variable pie_vars->accu_prob_overflows as the
variable pie_vars->accu_prob will never overflow.

Removing the variable pie_vars->accu_prob_overflows also reduces
the size of the structure pie_vars to exactly 64 bytes.

Signed-off-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in>
Signed-off-by: Gautam Ramakrishnan <gautamramk@gmail.com>
Signed-off-by: Leslie Monis <lesliemonis@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-04 13:25:55 -08:00
Leslie Monis 90baeb9dd2 pie: use term backlog instead of qlen
Remove ambiguity by using the term backlog instead of qlen when
representing the queue length in bytes.

Signed-off-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in>
Signed-off-by: Gautam Ramakrishnan <gautamramk@gmail.com>
Signed-off-by: Leslie Monis <lesliemonis@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-04 13:25:55 -08:00
Mohit P. Tahiliani ec97ecf1eb net: sched: add Flow Queue PIE packet scheduler
Principles:
  - Packets are classified on flows.
  - This is a Stochastic model (as we use a hash, several flows might
                                be hashed to the same slot)
  - Each flow has a PIE managed queue.
  - Flows are linked onto two (Round Robin) lists,
    so that new flows have priority on old ones.
  - For a given flow, packets are not reordered.
  - Drops during enqueue only.
  - ECN capability is off by default.
  - ECN threshold (if ECN is enabled) is at 10% by default.
  - Uses timestamps to calculate queue delay by default.

Usage:
tc qdisc ... fq_pie [ limit PACKETS ] [ flows NUMBER ]
                    [ target TIME ] [ tupdate TIME ]
                    [ alpha NUMBER ] [ beta NUMBER ]
                    [ quantum BYTES ] [ memory_limit BYTES ]
                    [ ecnprob PERCENTAGE ] [ [no]ecn ]
                    [ [no]bytemode ] [ [no_]dq_rate_estimator ]

defaults:
  limit: 10240 packets, flows: 1024
  target: 15 ms, tupdate: 15 ms (in jiffies)
  alpha: 1/8, beta : 5/4
  quantum: device MTU, memory_limit: 32 Mb
  ecnprob: 10%, ecn: off
  bytemode: off, dq_rate_estimator: off

Signed-off-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in>
Signed-off-by: Sachin D. Patil <sdp.sachin@gmail.com>
Signed-off-by: V. Saicharan <vsaicharan1998@gmail.com>
Signed-off-by: Mohit Bhasi <mohitbhasi1998@gmail.com>
Signed-off-by: Leslie Monis <lesliemonis@gmail.com>
Signed-off-by: Gautam Ramakrishnan <gautamramk@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-23 11:38:31 +01:00
Mohit P. Tahiliani 5205ea00cd net: sched: pie: export symbols to be reused by FQ-PIE
This patch makes the drop_early(), calculate_probability() and
pie_process_dequeue() functions generic enough to be used by
both PIE and FQ-PIE (to be added in a future commit). The major
change here is in the way the functions take in arguments. This
patch exports these functions and makes FQ-PIE dependent on
sch_pie.

Signed-off-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in>
Signed-off-by: Leslie Monis <lesliemonis@gmail.com>
Signed-off-by: Gautam Ramakrishnan <gautamramk@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-23 11:38:31 +01:00
Mohit P. Tahiliani b42a3d7c7c pie: improve comments and commenting style
Improve the comments along with the commenting style used to
describe the members of the structures and their initial values
in the init functions.

Signed-off-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in>
Signed-off-by: Leslie Monis <lesliemonis@gmail.com>
Signed-off-by: Gautam Ramakrishnan <gautamramk@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-23 11:38:31 +01:00
Mohit P. Tahiliani 2dfb1952a9 pie: rearrange structure members and their initializations
Rearrange the members of the structure such that closely
referenced members appear together and/or fit in the same
cacheline. Also, change the order of their initializations to
match the order in which they appear in the structure.

Signed-off-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in>
Signed-off-by: Leslie Monis <lesliemonis@gmail.com>
Signed-off-by: Gautam Ramakrishnan <gautamramk@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-23 11:38:31 +01:00
Mohit P. Tahiliani 1dbfc5e071 pie: use u8 instead of bool in pie_vars
Linux best practice recommends using u8 for true/false values in
structures.

Signed-off-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in>
Signed-off-by: Leslie Monis <lesliemonis@gmail.com>
Signed-off-by: Gautam Ramakrishnan <gautamramk@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-23 11:38:31 +01:00
Mohit P. Tahiliani cf4eeee5ff pie: rearrange macros in order of length
Rearrange macros in order of length and align the values to
improve readability.

Signed-off-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in>
Signed-off-by: Leslie Monis <lesliemonis@gmail.com>
Signed-off-by: Gautam Ramakrishnan <gautamramk@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-23 11:38:31 +01:00
Mohit P. Tahiliani 805a5a23a4 pie: use U64_MAX to denote (2^64 - 1)
Use the U64_MAX macro to denote the constant (2^64 - 1).

Signed-off-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in>
Signed-off-by: Leslie Monis <lesliemonis@gmail.com>
Signed-off-by: Gautam Ramakrishnan <gautamramk@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-23 11:38:31 +01:00
Mohit P. Tahiliani 84bf557fb0 net: sched: pie: move common code to pie.h
This patch moves macros, structures and small functions common
to PIE and FQ-PIE (to be added in a future commit) from the file
net/sched/sch_pie.c to the header file include/net/pie.h.
All the moved functions are made inline.

Signed-off-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in>
Signed-off-by: Leslie Monis <lesliemonis@gmail.com>
Signed-off-by: Gautam Ramakrishnan <gautamramk@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-23 11:38:30 +01:00