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From: "Michał Kazior" <kazikcz@gmail.com>
To: Wen Gong <wgong@codeaurora.org>
Cc: "Toke Høiland-Jørgensen" <toke@toke.dk>,
	ath10k@lists.infradead.org,
	"Johannes Berg" <johannes@sipsolutions.net>,
	linux-wireless <linux-wireless@vger.kernel.org>
Subject: Re: [PATCH 2/2] ath10k: Set sk_pacing_shift to 6 for 11AC WiFi chips
Date: Fri, 27 Jul 2018 14:33:35 +0200	[thread overview]
Message-ID: <CABvG-CUpcK=NbC1DaNw330W4YKwH7vb0ZFwPeWt20ODUa+QyXQ@mail.gmail.com> (raw)
In-Reply-To: <6715f59dc8e834cddd701c6f9ee9f344@codeaurora.org>

On 27 July 2018 at 11:39, Wen Gong <wgong@codeaurora.org> wrote:
> On 2018-07-26 21:02, Micha=C5=82 Kazior wrote:
>>
>> On 26 July 2018 at 13:45, Toke H=C3=B8iland-J=C3=B8rgensen <toke@toke.dk=
> wrote:
>>>
>>> Wen Gong <wgong@codeaurora.org> writes:
>>>
>>>> Upstream kernel has an interface to help adjust sk_pacing_shift to hel=
p
>>>> 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.
>>>
>>>
>>> When I tested this, a pacing shift of 8 was quite close to optimal as
>>> well for ath10k. Why are you getting different results?
>>>
>>>> Tested with QCA6174 PCI with firmware
>>>> WLAN.RM.4.4.1-00109-QCARMSWPZ-1, but this will also affect QCA9377 PCI=
.
>>>> 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:
>>
>>
>> Different firmware releases have different tx buffering
>> characteristics. In some 10.2 firmware running on QCA9888 you can have
>> up to 5ms of delayed aggregation. Ideally sk_pacing_shift should be
>> adjusted per firmware release. Maybe this should become part of the
>> ath10k firmware wrapping "fw features" stuff?
>>
> recently we do not want to do like this since no test data for each
> firmware.

All the more reason to *not* change the pacing shift from 8 to 6 for
entire ath10k because you have no idea what impact that is going to
have on other chips/firmwares, e.g. QCA4019, QCA9888X, QCA9984.


Micha=C5=82

WARNING: multiple messages have this Message-ID
From: "Michał Kazior" <kazikcz@gmail.com>
To: Wen Gong <wgong@codeaurora.org>
Cc: "Johannes Berg" <johannes@sipsolutions.net>,
	"Toke Høiland-Jørgensen" <toke@toke.dk>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	ath10k@lists.infradead.org
Subject: Re: [PATCH 2/2] ath10k: Set sk_pacing_shift to 6 for 11AC WiFi chips
Date: Fri, 27 Jul 2018 14:33:35 +0200	[thread overview]
Message-ID: <CABvG-CUpcK=NbC1DaNw330W4YKwH7vb0ZFwPeWt20ODUa+QyXQ@mail.gmail.com> (raw)
In-Reply-To: <6715f59dc8e834cddd701c6f9ee9f344@codeaurora.org>

On 27 July 2018 at 11:39, Wen Gong <wgong@codeaurora.org> wrote:
> On 2018-07-26 21:02, Michał Kazior wrote:
>>
>> On 26 July 2018 at 13:45, Toke Høiland-Jørgensen <toke@toke.dk> wrote:
>>>
>>> Wen Gong <wgong@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.
>>>
>>>
>>> When I tested this, a pacing shift of 8 was quite close to optimal as
>>> well for ath10k. Why are you getting different results?
>>>
>>>> Tested with QCA6174 PCI with firmware
>>>> WLAN.RM.4.4.1-00109-QCARMSWPZ-1, but this will also affect QCA9377 PCI.
>>>> 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:
>>
>>
>> Different firmware releases have different tx buffering
>> characteristics. In some 10.2 firmware running on QCA9888 you can have
>> up to 5ms of delayed aggregation. Ideally sk_pacing_shift should be
>> adjusted per firmware release. Maybe this should become part of the
>> ath10k firmware wrapping "fw features" stuff?
>>
> recently we do not want to do like this since no test data for each
> firmware.

All the more reason to *not* change the pacing shift from 8 to 6 for
entire ath10k because you have no idea what impact that is going to
have on other chips/firmwares, e.g. QCA4019, QCA9888X, QCA9984.


Michał

_______________________________________________
ath10k mailing list
ath10k@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/ath10k

  reply	other threads:[~2018-07-27 13:55 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-26  7:21 [PATCH 0/2] Change sk_pacing_shift in ieee80211_hw for best tx throughput Wen Gong
2018-07-26  7:21 ` Wen Gong
2018-07-26  7:21 ` [PATCH 1/2] mac80211: Save sk_pacing_shift to ieee80211_hw Wen Gong
2018-07-26  7:21   ` Wen Gong
2018-07-26 14:52   ` kbuild test robot
2018-07-26 14:52     ` kbuild test robot
2018-07-27  8:35     ` Wen Gong
2018-07-27  8:35       ` Wen Gong
2018-07-27  9:30       ` Kalle Valo
2018-07-27  9:30         ` Kalle Valo
2018-07-26  7:21 ` [PATCH 2/2] ath10k: Set sk_pacing_shift to 6 for 11AC WiFi chips Wen Gong
2018-07-26  7:21   ` Wen Gong
2018-07-26 11:45   ` Toke Høiland-Jørgensen
2018-07-26 11:45     ` Toke Høiland-Jørgensen
2018-07-26 13:02     ` Michał Kazior
2018-07-26 13:02       ` Michał Kazior
2018-07-27  9:39       ` Wen Gong
2018-07-27  9:39         ` Wen Gong
2018-07-27 12:33         ` Michał Kazior [this message]
2018-07-27 12:33           ` Michał Kazior
2018-07-27  9:29     ` Wen Gong
2018-07-27  9:29       ` Wen Gong
2018-07-27 20:06       ` Toke Høiland-Jørgensen
2018-07-27 20:06         ` Toke Høiland-Jørgensen
  -- strict thread matches above, loose matches on Subject: below --
2018-07-26  7:16 [PATCH 0/2] Change sk_pacing_shift in ieee80211_hw for best tx throughput Wen Gong
2018-07-26  7:16 ` [PATCH 2/2] ath10k: Set sk_pacing_shift to 6 for 11AC WiFi chips Wen Gong
2018-07-26  7:16   ` Wen Gong

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