On 22-07-25, 15:46, Dmitry Baryshkov wrote:
On Tue, Jul 22, 2025 at 05:50:08PM +0530, Jyothi Kumar Seerapu wrote:
On 7/19/2025 3:27 PM, Dmitry Baryshkov wrote:
On Mon, Jul 07, 2025 at 09:58:30PM +0530, Jyothi Kumar Seerapu wrote:
On 7/4/2025 1:11 AM, Dmitry Baryshkov wrote:
On Thu, 3 Jul 2025 at 15:51, Jyothi Kumar Seerapu
[Folks, would be nice to trim replies]
Could you please confirm if can go with the similar approach of unmap the processed TREs based on a fixed threshold or constant value, instead of unmapping them all at once?
I'd still say, that's a bad idea. Please stay within the boundaries of the DMA API.
I agree with the approach you suggested—it's the GPI's responsibility to manage the available TREs.
However, I'm curious whether can we set a dynamic watermark value perhaps half the available TREs) to trigger unmapping of processed TREs ? This would allow the software to prepare the next set of TREs while the hardware continues processing the remaining ones, enabling better parallelism and throughput.
Let's land the simple implementation first, which can then be improved. However I don't see any way to return 'above the watermark' from the DMA controller. You might need to enhance the API.
Traditionally, we set the dma transfers for watermark level and we get a interrupt. So you might want to set the callback for watermark level and then do mapping/unmapping etc in the callback. This is typical model for dmaengines, we should follow that well
BR