From: Dave Taht <dave@taht.net>
To: Wen Gong <wgong@qti.qualcomm.com>
Cc: "ath10k\@lists.infradead.org" <ath10k@lists.infradead.org>,
"linux-wireless\@vger.kernel.org"
<linux-wireless@vger.kernel.org>
Subject: Re: [PATCH 2/7] ath10k: change max RX bundle size from 8 to 32 for sdio
Date: Wed, 04 Sep 2019 06:34:29 -0700 [thread overview]
Message-ID: <87lfv4chi2.fsf@taht.net> (raw)
In-Reply-To: <259d8d7f8c2a4c428ae14ff211c83c1a@aptaiexm02f.ap.qualcomm.com> (Wen Gong's message of "Wed, 4 Sep 2019 04:43:21 +0000")
Wen Gong <wgong@qti.qualcomm.com> writes:
>> -----Original Message-----
>> From: Dave Taht <dave@taht.net>
>> Sent: Wednesday, September 4, 2019 12:10 AM
>> To: Wen Gong <wgong@qti.qualcomm.com>; ath10k@lists.infradead.org;
>> linux-wireless@vger.kernel.org
>> Subject: [EXT] Re: [PATCH 2/7] ath10k: change max RX bundle size from 8 to
>> 32 for sdio
>>
>>
>> In terms of deeply grokking what increasing buffering to achieve high
>> bandwidth on a testbench, vs what it can do to clobber latency in the
>> real world at low bandwidths, I tend to point folk at:
>>
>> https://www.youtube.com/watch?v=Rb-UnHDw02o&t=25m40s
>>
>> where I got a whole bunch of hackers to stand up and act like packets
>> in an aggregating FIFO wifi queue.
>>
>> This key section is only 8 minutes long, and I promise, y'all laugh
>> at least 3 times at the demonstration.
>>
>> At the time, also, the ath10k was so overbuffered that on one test
>> I could try to start 100 flows, and only get five.
>>
>> https://lwn.net/Articles/705884/
>>
>> and on my slides:
>>
>> https://blog.linuxplumbersconf.org/2016/ocw//system/presentations/3963/
>> original/linuxplumbers_wifi_latency-3Nov.pdf
>>
> Hi Dave,
> So your mean is change 8 to 32 will impact latency? It will increase latency of rx?
Heh. for rx, in this case, probably not!
I just get twitchy every time folk fiddle with buffer sizes. In one
recent case someone had fiddled with the interrupt polling interval on
something, going from 1ms to 10ms - it saved on cpu, but...
... just trying to make sure folk grok the tradoffs with a bit of
laughter.
carry on!
>
>>
>> 0xFFFEFFFF
next prev parent reply other threads:[~2019-09-04 13:34 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-20 11:55 [PATCH 0/7] ath10k: improve throughout of tcp/udp TX/RX of sdio Wen Gong
2019-08-20 11:55 ` [PATCH 1/7] ath10k: enable RX bundle receive for sdio Wen Gong
2019-08-27 7:40 ` Nicolas Boichat
2019-08-27 8:02 ` Wen Gong
2019-08-27 8:08 ` Nicolas Boichat
2019-08-28 4:25 ` Wen Gong
2019-08-20 11:55 ` [PATCH 2/7] ath10k: change max RX bundle size from 8 to 32 " Wen Gong
2019-08-20 12:23 ` Toke Høiland-Jørgensen
2019-08-21 6:01 ` Wen Gong
2019-08-21 10:02 ` Toke Høiland-Jørgensen
2019-08-27 7:42 ` Nicolas Boichat
2019-08-28 2:31 ` Wen Gong
2019-09-03 16:09 ` Dave Taht
2019-09-04 4:43 ` Wen Gong
2019-09-04 13:34 ` Dave Taht [this message]
2019-09-05 10:12 ` Wen Gong
2019-08-20 11:55 ` [PATCH 3/7] ath10k: add workqueue for RX path of sdio Wen Gong
2019-09-04 2:31 ` Wen Gong
2019-08-20 11:55 ` [PATCH 4/7] ath10k: disable TX complete indication of htt for sdio Wen Gong
2019-08-20 12:23 ` Toke Høiland-Jørgensen
2019-08-21 6:20 ` Wen Gong
2019-08-21 10:10 ` Toke Høiland-Jørgensen
2019-08-21 10:20 ` Wen Gong
2019-08-22 12:12 ` Toke Høiland-Jørgensen
2019-08-23 2:46 ` Wen Gong
2019-08-23 8:39 ` Toke Høiland-Jørgensen
2019-08-27 7:56 ` Nicolas Boichat
2019-08-28 4:24 ` Wen Gong
2019-09-04 2:33 ` Wen Gong
2019-08-20 11:55 ` [PATCH 5/7] ath10k: add htt TX bundle " Wen Gong
2019-09-04 2:34 ` Wen Gong
2019-08-20 11:55 ` [PATCH 6/7] ath10k: enable alt data of TX path " Wen Gong
2019-09-04 2:36 ` Wen Gong
2019-08-20 11:55 ` [PATCH 7/7] ath10k: enable napi on RX " Wen Gong
2019-09-04 2:37 ` Wen Gong
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