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From: Jiada Wang <jiada_wang@mentor.com>
To: Fabio Estevam <festevam@gmail.com>
Cc: Mark Brown <broonie@kernel.org>,
	"linux-spi@vger.kernel.org" <linux-spi@vger.kernel.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Sascha Hauer <s.hauer@pengutronix.de>
Subject: Re: [PATCH linux-next v3 1/1] spi: imx: dynamic burst length adjust for PIO mode
Date: Thu, 1 Jun 2017 00:55:53 -0700	[thread overview]
Message-ID: <592FC889.3020001@mentor.com> (raw)
In-Reply-To: <CAOMZO5D4O38M3ZQYxcT2w+oW=HBuk2WPMN7Ue4Va_gz3zbKZ=Q@mail.gmail.com>

Hello Fabio

On 05/29/2017 04:07 AM, Fabio Estevam wrote:
> Hi Jiada,
>
> On Fri, May 26, 2017 at 2:02 AM,<jiada_wang@mentor.com>  wrote:
>> From: Jiada Wang<jiada_wang@mentor.com>
>>
>> previously burst length (BURST_LENGTH) is always set to equal
>> to bits_per_word, causes a 10us gap between each word in
>> transfer, which significantly affects performance.
>>
>> This patch uses 32 bits transfer to simulate lower bits transfer,
>> and adjusts burst length runtimely to use biggeest burst length
>> as possible to reduce the gaps in transfer for PIO mode.
> Just curious: what is the performance gain you observe with this patch?
I did some performance test with 576/384/192 bytes data,
following is the result between the test w & w/o this patch
(ecspi controller works in PIO and loopback mode)

with this patch:
bytes      bpw      time (ms)
576         8           9.2
576         16         9.2
384         8            6.2
192          8           3.1

without this patch
bytes      bpw      time(ms)
576           8           14.4
576           16          11.6
384           8            9.6
384           16          7.8
192           8            4.8
192           16          3.9


Thanks,
Jiada

      reply	other threads:[~2017-06-01  7:56 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-26  5:02 [PATCH linux-next v3 1/1] spi: imx: dynamic burst length adjust for PIO mode jiada_wang
2017-05-26  5:02 ` jiada_wang-nmGgyN9QBj3QT0dZR+AlfA
2017-05-29  9:50 ` Sascha Hauer
2017-05-29  9:50   ` Sascha Hauer
2017-06-01 11:58   ` Jiada Wang
2017-06-01 11:58     ` Jiada Wang
2017-06-02  5:38     ` Sascha Hauer
2017-06-02  5:38       ` Sascha Hauer
2017-06-09  5:09       ` Jiada Wang
2017-06-09  5:09         ` Jiada Wang
2017-06-09  5:46         ` Sascha Hauer
2017-06-09  5:46           ` Sascha Hauer
2017-05-29 11:07 ` Fabio Estevam
2017-05-29 11:07   ` Fabio Estevam
2017-06-01  7:55   ` Jiada Wang [this message]

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