[Make-wifi-fast] [bbr-dev] Aggregating without bloating - hard times for tcp and wifi

[Muhammad Ahsan]

Hi dev group guys,

 

I need to use sysctl to set ms value for net.ipv4.tcp_limit_output_ms .

 

The TSQ patch attached is not working or letting me do that . I am on linux 5.13.12 

Manually changing tx_sk_pacing_shift <https://elixir.bootlin.com/linux/latest/C/ident/tx_sk_pacing_shift>  = 7;  variable in main.c  needs to recompile kernel everytime…

 

I need to have sysctl to control the ms value , to set  2TSQ,4TSQ,8TSQ  etc for my wifi chipset.

 

I will be thankful if anyone can help me in it. 

 

 

Rgds,

Ahsan

 

 

 

From: 'Neal Cardwell' via BBR Development <bbr-dev at googlegroups.com> 
Sent: Wednesday, November 23, 2022 1:10 AM
To: Bob McMahon <bob.mcmahon at broadcom.com>
Cc: Dave Taht <dave.taht at gmail.com>; Make-Wifi-fast <make-wifi-fast at lists.bufferbloat.net>; bloat <bloat at lists.bufferbloat.net>; BBR Development <bbr-dev at googlegroups.com>
Subject: Re: [bbr-dev] Aggregating without bloating - hard times for tcp and wifi

 

On Tue, Nov 22, 2022 at 2:43 PM 'Bob McMahon' via BBR Development <bbr-dev at googlegroups.com <mailto:bbr-dev at googlegroups.com> > wrote:

Thanks for sharing this. Curious about how the xTSQ value can be set? Can it be done with sysctl?

We continue our analysis by using the ms-version of TSQ patch, which enables the tune of the TSQ size allowing each TCP variant to enqueue more than 1 ms of data at the current TCP rate. In particular, we allow to enqueue the equivalent of x ms of data, naming each test xTSQ, with x being an integer value. It is important to notice that this patch has been included in the Linux kernel mainline, and each Wi-Fi driver can now set the desired xTSQ value.

 

I believe they are setting the xTSQ value using the sk_pacing_shift field, which was added here:

   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3a9b76fd0db9f0d426533f96a68a62a58753a51e

 

AFAIK the intent is only for drivers to set that, and there's no sysctl for that, but of course you could add a sysctl for testing if you wanted. :-)

 

cheers,

neal

 

 

 

Another thing that could be interesting is the WiFi aggregation stop reasons, e.g. how many times agg stopped per hitting the max mpdu per ampdu vs the software fifo going empty (i.e. no more packets available to the driver from the TCP stack) per that TXOP.

Finally, many (most?) APs are forwarding and feeding packets at at the hardware level so not sure that the linux stack matters as much for an AP based analysis, particularly when considering multi user transmissions, i.e. multiple WiFi clients are active and sharing TXOPs.

Bob

On Mon, Nov 21, 2022 at 10:04 PM Dave Taht <dave.taht at gmail.com <mailto:dave.taht at gmail.com> > wrote:

This paper came out last month. Good work, really exhaustive look at
two chipsets, multiple congestion controls and the interactions with
TSQ, with
lots and lots of flent.

https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=9772053

as for wifi6... don't make me start talking about wifi6... but some of
these tests look like a good baseline to start comparing the ath11k,
mt79, etc..

Paper kind of misses the negative impact of AQL in the ath10k (and
most likely also the mt76 and mt79 chips)

-- 
This song goes out to all the folk that thought Stadia would work:
https://www.linkedin.com/posts/dtaht_the-mushroom-song-activity-6981366665607352320-FXtz
Dave Täht CEO, TekLibre, LLC

-- 
You received this message because you are subscribed to the Google Groups "BBR Development" group.
To unsubscribe from this group and stop receiving emails from it, send an email to bbr-dev+unsubscribe at googlegroups.com <mailto:bbr-dev%2Bunsubscribe at googlegroups.com> .
To view this discussion on the web visit https://groups.google.com/d/msgid/bbr-dev/CAA93jw6yJU10wh9ajqX4yW2AvnJPStyWAAcV4%2BoQ8wSGsJgKZA%40mail.gmail.com.


This electronic communication and the information and any files transmitted with it, or attached to it, are confidential and are intended solely for the use of the individual or entity to whom it is addressed and may contain information that is confidential, legally privileged, protected by privacy laws, or otherwise restricted from disclosure to anyone else. If you are not the intended recipient or the person responsible for delivering the e-mail to the intended recipient, you are hereby notified that any use, copying, distributing, dissemination, forwarding, printing, or copying of this e-mail is strictly prohibited. If you received this e-mail in error, please return the e-mail to the sender, delete it from your computer, and destroy any printed copy of it. 

-- 
You received this message because you are subscribed to the Google Groups "BBR Development" group.
To unsubscribe from this group and stop receiving emails from it, send an email to bbr-dev+unsubscribe at googlegroups.com <mailto:bbr-dev+unsubscribe at googlegroups.com> .
To view this discussion on the web visit https://groups.google.com/d/msgid/bbr-dev/CAHb6LvrK_exkt_rbukYkF4_hwPXyy9T%2BZNGzdK79x91RrK49Mg%40mail.gmail.com <https://groups.google.com/d/msgid/bbr-dev/CAHb6LvrK_exkt_rbukYkF4_hwPXyy9T%2BZNGzdK79x91RrK49Mg%40mail.gmail.com?utm_medium=email&utm_source=footer> .

-- 
You received this message because you are subscribed to the Google Groups "BBR Development" group.
To unsubscribe from this group and stop receiving emails from it, send an email to bbr-dev+unsubscribe at googlegroups.com <mailto:bbr-dev+unsubscribe at googlegroups.com> .
To view this discussion on the web visit https://groups.google.com/d/msgid/bbr-dev/CADVnQyn9OSxPcF2JsUHdiWLTvAAdN5vs1uyiRBL0AS8yH8niYw%40mail.gmail.com <https://groups.google.com/d/msgid/bbr-dev/CADVnQyn9OSxPcF2JsUHdiWLTvAAdN5vs1uyiRBL0AS8yH8niYw%40mail.gmail.com?utm_medium=email&utm_source=footer> .

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.bufferbloat.net/pipermail/make-wifi-fast/attachments/20221124/26b9b682/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: TSQ.patch
Type: application/octet-stream
Size: 4670 bytes
Desc: not available
URL: <https://lists.bufferbloat.net/pipermail/make-wifi-fast/attachments/20221124/26b9b682/attachment-0001.obj>