From: David Lechner <dlechner@baylibre.com>
To: Dharma Balasubiramani <dharma.b@microchip.com>,
Kamel Bouhara <kamel.bouhara@bootlin.com>,
William Breathitt Gray <wbg@kernel.org>,
Nicolas Ferre <nicolas.ferre@microchip.com>,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
Claudiu Beznea <claudiu.beznea@tuxon.dev>
Cc: linux-arm-kernel@lists.infradead.org, linux-iio@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] counter: microchip-tcb-capture: Add DMA support for TC_RAB register reads
Date: Thu, 29 May 2025 10:33:20 -0500 [thread overview]
Message-ID: <b45ea46b-3e17-4cb9-8e69-9eea0a3f8241@baylibre.com> (raw)
In-Reply-To: <20250528-mchp-tcb-dma-v1-2-083a41fb7b51@microchip.com>
On 5/28/25 1:13 AM, Dharma Balasubiramani wrote:
> Add optional DMA-based data transfer support to read the TC_RAB register,
> which provides the next unread captured value from either RA or RB. This
> improves performance and offloads CPU when mchp,use-dma-cap is enabled in
> the device tree.
It looks like this is using DMA to read a single register in the implementation
of a sysfs read. Do you have measurements to show the performance difference?
I find it hard to believe that this would actually make a significant difference
compared to the overhead of the read syscall to read the sysfs attribute.
next prev parent reply other threads:[~2025-05-29 15:33 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-28 6:13 [PATCH 0/2] TCB: Add DMA support to read the capture register AB Dharma Balasubiramani
2025-05-28 6:13 ` [PATCH 1/2] counter: microchip-tcb-capture: Retrieve and map parent base address Dharma Balasubiramani
2025-05-28 6:13 ` [PATCH 2/2] counter: microchip-tcb-capture: Add DMA support for TC_RAB register reads Dharma Balasubiramani
2025-05-29 9:21 ` kernel test robot
2025-05-29 15:33 ` David Lechner [this message]
2025-06-04 6:15 ` Dharma.B
2025-06-04 13:21 ` David Lechner
2025-05-29 15:26 ` [PATCH 0/2] TCB: Add DMA support to read the capture register AB David Lechner
2025-06-04 6:17 ` Dharma.B
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