[Make-wifi-fast] QCut - "Understanding on-device bufferbloat for cellular upload", Guo et al

[Make-wifi-fast] QCut - "Understanding on-device bufferbloat for cellular upload", Guo et al

[Rich Brown]

Google Alerts sent a link to this paper: "Understanding on-device bufferbloat for cellular upload" available at: http://dl.acm.org/citation.cfm?id=2987490 (ACM Paywall...)

In my two-minute skim of the paper, I see they describe how latency gets bad on cellular devices (no kidding) and then propose QCut, a queue inserted between the qdisc and the hardware. They say:

---
... QCut operates in the kernel space and takes as input only information of buffer occupancy and transmission statistics, which is exposed by most cellular radio firmware from Qualcomm and likely other vendors.

Since directly limiting the firmware buffer occupancy is difficult, QCut controls the firmware queuing delay indirectly in the kernel by controlling how fast packets from Qdisc flow into the firmware buffer. QCUT estimates the radio firmware buffer occupancy and queuing delay to decide the transmission of packets to the firmware dynamically...
---

Their analysis and charts show that QCut helps a lot.

I found it interesting that they make measurements with both weak and strong signal strength, to indicate the hits that are caused by differing signal strength.

Enjoy!

Rich

Re: [Make-wifi-fast] [Bloat] QCut - "Understanding on-device bufferbloat for cellular upload", Guo et al

[Stephen Hemminger]

On Tue, 15 Nov 2016 12:00:29 -0500
Rich Brown <richb.hanover@gmail.com> wrote:

> Google Alerts sent a link to this paper: "Understanding on-device bufferbloat for cellular upload" available at: http://dl.acm.org/citation.cfm?id=2987490 (ACM Paywall...)
> 
> In my two-minute skim of the paper, I see they describe how latency gets bad on cellular devices (no kidding) and then propose QCut, a queue inserted between the qdisc and the hardware. They say:
> 
> ---
> ... QCut operates in the kernel space and takes as input only information of buffer occupancy and transmission statistics, which is exposed by most cellular radio firmware from Qualcomm and likely other vendors.
> 
> Since directly limiting the firmware buffer occupancy is difficult, QCut controls the firmware queuing delay indirectly in the kernel by controlling how fast packets from Qdisc flow into the firmware buffer. QCUT estimates the radio firmware buffer occupancy and queuing delay to decide the transmission of packets to the firmware dynamically...
> ---
> 
> Their analysis and charts show that QCut helps a lot.
> 
> I found it interesting that they make measurements with both weak and strong signal strength, to indicate the hits that are caused by differing signal strength.
> 
> Enjoy!
> 
> Rich
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Reinvention of BQL?