[FS#294] linksys 1200ac (and most likely other mvneta) has a multi-flow lockout problem

[LEDE Bugs]

The following task has a new comment added:

FS#294 - linksys 1200ac (and most likely other mvneta) has a multi-flow lockout problem
User who did this - Dave Täht (dtaht)

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I have tested the mvneta with this and it no longer has the lockout behavior, and
can, indeed push netperf in one direction or the other at 1Gbit, with 12 flows.

I did not test "through" the router at a gbit.

It can't do both 12 flows up and down at the same time. (about 600mbit each way).

It might be good for the driver to stop exposing "mq" at all to the higher level bits of the stack, as allocating 8 fq_codel instances is somewhat wasteful, and confusing.

I have also seen bql "working" in this case.

I support closure until this is better fixed upstream.



2017-01-16 19:05 GMT+01:00 Felix Fietkau :
> On 2017-01-16 18:59, Dave Taht wrote:
>> On Mon, Jan 16, 2017 at 9:28 AM, Marcin Wojtas  wrote:
>>> I just took a look in the LEDE master branch and found his work-around:
>>>
>>> https://git.lede-project.org/?p=source.git;a=blob;f=target/linux/mvebu/patches-4.4/400-mvneta-tx-queue-workaround.patch;h=5dba311d93a6d325fc110b8218d56209bd78e9dd;hb=2e1f6f1682d3974d8ea52310e460f1bbe470390f#l1
>>>
>>> He simply uses TXQ0 for entire traffic. I'm not aware of any problem
>>> in HW. Maybe he can send a description of his findings to the kernel
>>> lists and then I'd poke Marvell so that it could at least try to get
>>> into their network team bug system?
> To me the behavior looks like the hardware is configured to service the
> queues in a fixed priority scheme. If I put the system under heavy load,
> one queue gets its packets out all the time, whereas all the other
> queues starve completely (>900 Mbit/s on one queue vs  I've tried to resolve this myself by looking at the data sheet and
> playing with the queue configuration registers, but didn't get anywhere
> with that.
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More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=294#comment1320