Opened 3 years ago

Closed 3 years ago

Last modified 3 years ago

#19641 closed enhancement (fixed)

Please enable "Proportional Integral controller Enhanced (PIE) scheduler" (CONFIG_NET_SCH_PIE)

Reported by: anonymous Owned by: developers
Priority: normal Milestone: Chaos Calmer 15.05
Component: kernel Version: Trunk
Keywords: Proportional Integral controller Enhanced sch_pie qdisc PIE AQM NET_SCH_PIE CONFIG_NET_SCH_PIE Cc:


PIE is a new AQM like (FQ_)CoDel which has been available since Linux 3.14

It doesn't use packet timestamping, so it incurs less overhead than (FQ_)CoDel according to the paper.

Maybe it can be added to KernelPackage/sched (i.e. add CONFIG_NET_SCH_PIE to package/kernel/linux/modules/

Patch is attached.


Is it possible to add "Deficit Round Robin scheduler" (CONFIG_NET_SCH_DRR) too? Ticket 17852 was created some time ago.

Attachments (1) (453 bytes) - added by anonymous 3 years ago.

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Change History (6)

Changed 3 years ago by anonymous

comment:1 Changed 3 years ago by dtaht

the sqm-scripts support pie (and multiple other qdiscs) if it were built outside the cerowrt project.

What is lacking for adding pie support to openwrt: is any proof that it is more effective than fq_codel in any circumstance.

While it is claimed it uses less cpu resources in the paper, it turns out that htb + {pie or fq_codel} the run time cost is dominated by htb.

I would like all of the newer advanced qdiscs available for linux (pie, drr, hhf, and the new cake ( ) being made available in openwrt mainline but I think it would be better if it/they ended up in their own separately installable packages.

comment:2 Changed 3 years ago by anonymous

I agree that it's better to have them in optional packages, but I didn't want the changes to look like a hassle to implement, so I tried to keep it simple (i.e. 1 line change) to avoid discouragement.

comment:3 Changed 3 years ago by anonymous

Please close this ticket, it's resolved in r45885.

I'm looking forward to seeing sch_drr (CONFIG_NET_SCH_DRR) too. #17852

comment:4 Changed 3 years ago by florian

  • Resolution set to fixed
  • Status changed from new to closed

comment:5 Changed 3 years ago by dtaht

If you are going to add pie and fq to this package, I favor adding drr also, as it is what uses (with fq_codel) so successfully.

In the longer term, making this a meta package and breaking out the other schedulers into their own seems more appropo. QFQ is also of interest.

I note that fq makes me nervous on memory limited boxes. It is a darn good choice for *servers* that run tcp *only*. It is not for routers, routing.

There are also a fq_pie and cake still out of tree that I would like to find a way to include optionally as well, but they are evolving too fast to have in mainline openwrt.

The barrier to kmod-sch_cake, kmod-sch_fq_pie is presently that there seems no way to override the default iproute2 package, so I think the way forward there is to create a new iproute2-adv package (containing those two)?

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