[Cerowrt-devel] looking over ampdu stats
David P. Reed
dpreed at reed.com
Mon Jan 20 10:09:04 EST 2014
It's worth remembering that while aggregation of data in single units might reduce overhead, end to end latency is far more critical to most Internet apps.
Focusing on optimizing throughput for the last few percent in corner cases is NOT desirable. In fact, it is the cause of pervasive buffer bloated designs, and the creator of "Daddy broke the Internet" scenarios.
Since LTE is badly configured in the field for Internet use, causing denial of service to many users because of bloated (multisecond to drain) queues, I would stop focusing on this, which is only a 10 percent issue. Multisecond bloat is a disaster. You are fiddling while Rome burns imo.
On Jan 19, 2014, Sujith Manoharan <sujith at msujith.org> wrote:
>Dave Taht wrote:
>> Gotcha. I went later (at felix's urging) to look at the rc_stats
>> and that showed some decent averages for the actual number of
>> packets in the AMPDU. Never managed to get it much above 11,
>> regardless of what I set be_qlen to...
>Yes, something seems to be wrong.
>Using just 1 stream with iperf, the average A-MPDU length never
>goes above 10 and the throughput is about 90 Mbps.
>Using 4 iperf streams (using -P), the average A-MPDU length goes up to
>and throughput reaches about 102 Mbps.
>This is with HT20. Using HT40 shows the behavior for 1 iperf stream.
>Cerowrt-devel mailing list
>Cerowrt-devel at lists.bufferbloat.net
Sent from my Android device with <a href=https://play.google.com/store/apps/details?id=com.onegravity.k10.pro2><b>K-@ Mail</b></a>. Please excuse my brevity.
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