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@xxxxxxxxxxxxxxxxxxxxxxxxxx; hch@xxxxxx; robin.murphy@xxxxxxx;
m.szyprowski@xxxxxxxxxxx
Cc: Linuxarm <linuxarm@xxxxxxxxxx>; linux-kselftest@xxxxxxxxxxxxxxx; xuwei
(O) <xuwei5@xxxxxxxxxx>; Song Bao Hua (Barry Song)
<song.bao.hua@xxxxxxxxxxxxx>; Joerg Roedel <joro@xxxxxxxxxx>; Will Deacon
<will@xxxxxxxxxx>; Shuah Khan <shuah@xxxxxxxxxx>
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@xxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Cc: Robin Murphy <robin.murphy@xxxxxxx>
Signed-off-by: Barry Song <song.bao.hua@xxxxxxxxxxxxx>
---
Thanks,
John
