From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: Jakub Kicinski <kuba@kernel.org>, gautamramk@gmail.com
Cc: netdev@vger.kernel.org,
"Mohit P. Tahiliani" <tahiliani@nitk.edu.in>,
Jamal Hadi Salim <jhs@mojatatu.com>,
"David S . Miller" <davem@davemloft.net>,
Dave Taht <dave.taht@gmail.com>,
Leslie Monis <lesliemonis@gmail.com>,
"Sachin D . Patil" <sdp.sachin@gmail.com>,
"V . Saicharan" <vsaicharan1998@gmail.com>,
Mohit Bhasi <mohitbhasi1998@gmail.com>
Subject: Re: [PATCH net-next v3 2/2] net: sched: add Flow Queue PIE packet scheduler
Date: Mon, 13 Jan 2020 12:44:38 +0100 [thread overview]
Message-ID: <87eew3wpg9.fsf@toke.dk> (raw)
In-Reply-To: <20200112173624.5f7b754b@cakuba>
Jakub Kicinski <kuba@kernel.org> writes:
> On Fri, 10 Jan 2020 11:56:57 +0530, gautamramk@gmail.com wrote:
>> From: "Mohit P. Tahiliani" <tahiliani@nitk.edu.in>
>>
>> Principles:
>> - Packets are classified on flows.
>> - This is a Stochastic model (as we use a hash, several flows might
>> be hashed on 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 is at 10% by default.
>> - Uses timestamps to calculate queue delay by default.
>>
>> Usage:
>> tc qdisc ... fq_pie [ limit PACKETS ] [ flows NUMBER ]
>> [ alpha NUMBER ] [ beta NUMBER ]
>> [ target TIME us ] [ tupdate TIME us ]
>> [ memory_limit BYTES ] [ quantum BYTES ]
>> [ ecnprob PERCENTAGE ] [ [no]ecn ]
>> [ [no]bytemode ] [ [no_]dq_rate_estimator ]
>>
>> defaults:
>> limit: 10240 packets, flows: 1024
>> alpha: 1/8, beta : 5/4
>> target: 15 ms, tupdate: 15 ms (in jiffies)
>> memory_limit: 32 Mb, quantum: device MTU
>> ecnprob: 10%, ecn: off
>> bytemode: off, dq_rate_estimator: off
>
> Some reviews below, but hopefully someone who knows more about qdiscs
> will still review :)
I looked it over, and didn't find anything you hadn't already pointed
out below. It's pretty obvious that this started out as a copy of
sch_fq_codel. Which is good, because that's pretty solid. And bad,
because that means it introduces another almost-identical qdisc without
sharing any of the code...
I think it would be worthwhile to try to consolidate things at some
point. Either by just merging code from fq_{codel,pie}, but another
option would be to express fq_codel and fq_pie using the fq{,_impl}.h
includes. Maybe even sch_cake as well, but that may take a bit more
work. Not sure if we should require this before merging fq_pie, or just
leave it as a possible enhancement for later? WDYT?
-Toke
next prev parent reply other threads:[~2020-01-13 11:44 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-10 6:26 [PATCH net-next v3 0/2] net: sched: add Flow Queue PIE packet scheduler gautamramk
2020-01-10 6:26 ` [PATCH net-next v3 1/2] net: sched: pie: refactor code gautamramk
2020-01-10 6:26 ` [PATCH net-next v3 2/2] net: sched: add Flow Queue PIE packet scheduler gautamramk
2020-01-13 1:36 ` Jakub Kicinski
2020-01-13 11:44 ` Toke Høiland-Jørgensen [this message]
2020-01-13 12:19 ` Jakub Kicinski
2020-01-13 12:33 ` Toke Høiland-Jørgensen
2020-01-13 13:34 ` Gautam Ramakrishnan
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