Wen Gong <wg...@qti.qualcomm.com> writes:
>> -----Original Message-----
>> From: ath10k <ath10k-boun...@lists.infradead.org> On Behalf Of Toke
>> Sent: Wednesday, August 8, 2018 6:44 PM
>> To: Wen Gong <wg...@codeaurora.org>; email@example.com;
>> Cc: linux-wirel...@vger.kernel.org
>> Subject: Re: [PATCH v2 2/2] ath10k: Set sk_pacing_shift to 6 for 11AC WiFi
>> Wen Gong <wg...@codeaurora.org> writes:
>> > Upstream kernel has an interface to help adjust sk_pacing_shift to
>> > help improve TCP UL throughput.
>> > The sk_pacing_shift is 8 in mac80211, this is based on test with 11N
>> > WiFi chips with ath9k. For QCA6174/QCA9377 PCI 11AC chips, the 11AC
>> > VHT80 TCP UL throughput testing result shows 6 is the optimal.
>> > Overwrite the sk_pacing_shift to 6 in ath10k driver for QCA6174/9377 PCI.
>> > Tested with QCA6174 PCI with firmware
>> > WLAN.RM.4.4.1-00109-QCARMSWPZ-1, but this will also affect QCA9377
>> > It's not a regression with new firmware releases.
>> > There have 2 test result of different settings:
>> > ARM CPU based device with QCA6174A PCI with different
>> > sk_pacing_shift:
>> > sk_pacing_shift throughput(Mbps) CPU utilization
>> > 6 500(-P5) ~75% idle, Focus on CPU1: ~14%idle
>> > 7 454(-P5) ~80% idle, Focus on CPU1: ~4%idle
>> > 8 288 ~90% idle, Focus on CPU1: ~35%idle
>> > 9 ~200 ~92% idle, Focus on CPU1: ~50%idle
>> > 5G TCP UL VTH80 on X86 platform with QCA6174A PCI with
>> > sk_packing_shift set to 6:
>> > tcp_limit_output_bytes throughput(Mbps)
>> > default(262144)+1 Stream 336
>> > default(262144)+2 Streams 558
>> > default(262144)+3 Streams 584
>> > default(262144)+4 Streams 602
>> > default(262144)+5 Streams 598
>> > changed(2621440)+1 Stream 598
>> > changed(2621440)+2 Streams 601
>> You still haven't provided any latency numbers for these tests, which makes
>> it impossible to verify that setting sk_pacing_shift to 6 is the right
>> As I said before, from your numbers I suspect the right setting is actually
>> which would be 10-20ms less latency under load; way more important than
>> ~50 Mbps...
> Hi Toke,
> Could you give the command line for the latency test?
> I used the command but test failed:
> flent tcp_download -p 1 -l 60 -H 192.168.1.5 -t text-to-be-included-in-plot
> -o file1.png
> error loading plotter: unable to find plot configuration "1"
Try something like:
flent -H 192.168.1.5 -t "sk_pacing_shift 7" tcp_nup --test-parameter
This will note the value of sk_pacing_shift you are testing in the data
file (so change that as appropriate), and you can vary the number of TCP
streams by changing the upload_streams parameter.
Note that in this case I'm assuming you are running Flent on the device
with the kernel you are trying to test, so you want a TCP transfer going
*from* the device. If not, change "tcp_nup" to "tcp_ndown" and
"upload_streams" to "download_streams". Upload is netperf TCP_STREAM
test, and download is TCP_MAERTS.
When running the above command you'll get a summary output on the
terminal that you can paste on the list; and also a data file to plot
things form. For instance, you can do something like 'flent -p ping_cdf
*.flent.gz' to get a CDF plot of all your test results afterwards. You
are also very welcome to send me the .flent.gz data files and I'll take
a look to make sure everything looks reasonable :)
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