linux-kernel - Re: [PATCH v3 2/3] spi: s3c64xx: add sleep during transfer

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Date:   Fri, 5 May 2023 11:09:29 +0200
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Jaewon Kim <jaewon02.kim@...sung.com>,
        Andi Shyti <andi@...zian.org>, Mark Brown <broonie@...nel.org>,
        Alim Akhtar <alim.akhtar@...sung.com>
Cc:     linux-spi@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Chanho Park <chanho61.park@...sung.com>
Subject: Re: [PATCH v3 2/3] spi: s3c64xx: add sleep during transfer

On 02/05/2023 08:28, Jaewon Kim wrote:
> In polling mode, the status register is continuously read to check data
> transfer completion. It can cause excessive CPU usage.
> To reduce this, we can calculate the transfer time and put the sleep during
> transfer.
> 
> When test on ExynosAuto9 SADK board, throughput remained the same, but
> 100% CPU utilization decreased to 40%.
> 
> Signed-off-by: Jaewon Kim <jaewon02.kim@...sung.com>
> ---

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>

Best regards,
Krzysztof