From: Jaewon Kim <jaewon02.kim@samsung.com>
To: Mark Brown <broonie@kernel.org>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
Andi Shyti <andi@etezian.org>,
Alim Akhtar <alim.akhtar@samsung.com>,
Rob Herring <robh+dt@kernel.org>,
linux-spi@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Chanho Park <chanho61.park@samsung.com>
Subject: Re: [PATCH 3/3] spi: s3c64xx: support interrupt based pio mode
Date: Tue, 4 Apr 2023 22:15:05 +0900 [thread overview]
Message-ID: <e01900f0-e5ac-d2f9-9e1b-c5cc35d21713@samsung.com> (raw)
In-Reply-To: <61a67466-3467-4f71-bc27-d660e37c08ac@sirena.org.uk>
Hello Mark,
On 23. 4. 4. 21:58, Mark Brown wrote:
> On Tue, Apr 04, 2023 at 03:00:11PM +0900, Jaewon Kim wrote:
>
>> This patch adds IRQ based PIO mode instead of cpu polling.
>> By using the FIFO trigger level, interrupts are received.
>> CPU consumption is reduced in PIO mode because registers are not
>> constantly checked.
> Is there some lower limit where it's still worth using polling, for
> example for just one or two bytes like a register address? Taking an
> interrupt isn't free...
I did not considers lower limit.
According to your review, interrupt seems to be called too often.
However, It can't prevent the CPU utilization going to 100% during spi
transmission.
We will give more consideration and deliver a better solution to the
next patch version.
Thanks
Jaewon Kim
next prev parent reply other threads:[~2023-04-04 13:17 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20230404061409epcas2p2e97fff5459b405db0d5a206e2ad38f82@epcas2p2.samsung.com>
2023-04-04 6:00 ` [PATCH 0/3] spi: s3c64xx: improve SPI polling mode Jaewon Kim
[not found] ` <CGME20230404061409epcas2p15750d5844aa8d3655d1bfd094fac14a9@epcas2p1.samsung.com>
2023-04-04 6:00 ` [PATCH 1/3] spi: s3c64xx: support spi polling mode using devicetree Jaewon Kim
2023-04-04 10:54 ` Mark Brown
2023-04-04 11:17 ` Jaewon Kim
2023-04-04 11:41 ` Mark Brown
2023-04-04 12:22 ` Jaewon Kim
2023-04-04 12:41 ` Mark Brown
2023-04-05 5:42 ` Krzysztof Kozlowski
2023-04-05 11:42 ` Jaewon Kim
[not found] ` <CGME20230404061409epcas2p36402f7a84406ba9d831dcff0ddd994e9@epcas2p3.samsung.com>
2023-04-04 6:00 ` [PATCH 2/3] spi: dt-bindings: samsung: add samsung,spi-polling property Jaewon Kim
2023-04-04 12:36 ` Rob Herring
[not found] ` <CGME20230404061409epcas2p2b12a9cac014907e3930795cb67cb6040@epcas2p2.samsung.com>
2023-04-04 6:00 ` [PATCH 3/3] spi: s3c64xx: support interrupt based pio mode Jaewon Kim
2023-04-04 12:58 ` Mark Brown
2023-04-04 13:15 ` Jaewon Kim [this message]
2023-04-04 13:33 ` Mark Brown
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