On 10/11/2020 08:10, Song Bao Hua (Barry Song) wrote:
Hello Robin, Christoph, Any further comment? John suggested that "depends on DEBUG_FS" should be added in Kconfig. I am collecting more comments to send v4 together with fixing this minor issue :-)
Thanks Barry
-----Original Message----- From: Song Bao Hua (Barry Song) Sent: Monday, November 2, 2020 9:07 PM To: iommu@lists.linux-foundation.org; hch@lst.de; robin.murphy@arm.com; m.szyprowski@samsung.com Cc: Linuxarm linuxarm@huawei.com; linux-kselftest@vger.kernel.org; xuwei (O) xuwei5@huawei.com; Song Bao Hua (Barry Song) song.bao.hua@hisilicon.com; Joerg Roedel joro@8bytes.org; Will Deacon will@kernel.org; Shuah Khan shuah@kernel.org Subject: [PATCH v3 1/2] dma-mapping: add benchmark support for streaming DMA APIs
Nowadays, there are increasing requirements to benchmark the performance of dma_map and dma_unmap particually while the device is attached to an IOMMU.
This patch enables the support. Users can run specified number of threads to do dma_map_page and dma_unmap_page on a specific NUMA node with the specified duration. Then dma_map_benchmark will calculate the average latency for map and unmap.
A difficulity for this benchmark is that dma_map/unmap APIs must run on a particular device. Each device might have different backend of IOMMU or non-IOMMU.
So we use the driver_override to bind dma_map_benchmark to a particual device by: For platform devices: echo dma_map_benchmark > /sys/bus/platform/devices/xxx/driver_override echo xxx > /sys/bus/platform/drivers/xxx/unbind echo xxx > /sys/bus/platform/drivers/dma_map_benchmark/bind
Hi Barry,
For PCI devices: echo dma_map_benchmark > /sys/bus/pci/devices/0000:00:01.0/driver_override echo 0000:00:01.0 > /sys/bus/pci/drivers/xxx/unbind echo 0000:00:01.0 > /sys/bus/pci/drivers/dma_map_benchmark/bind
Do we need to check if the device to which we attach actually has DMA mapping capability?
Cc: Joerg Roedel joro@8bytes.org Cc: Will Deacon will@kernel.org Cc: Shuah Khan shuah@kernel.org Cc: Christoph Hellwig hch@lst.de Cc: Marek Szyprowski m.szyprowski@samsung.com Cc: Robin Murphy robin.murphy@arm.com Signed-off-by: Barry Song song.bao.hua@hisilicon.com
Thanks, John