Hi, On 14/12/20 1:43 pm, Peter Ujfalusi wrote: > Hi, > > Newer members of the KS3 family (after AM654) have support for burst_size > configuration for each DMA channel. > > The HW default value is 64 bytes but on higher throughput channels it can be > increased to 256 bytes (UCHANs) or 128 byes (HCHANs). > > Aligning the buffers and length of the transfer to the burst size also increases > the throughput. > > Numbers gathered on j721e (UCHAN pair): > echo 8000000 > /sys/module/dmatest/parameters/test_buf_size > echo 2000 > /sys/module/dmatest/parameters/timeout > echo 50 > /sys/module/dmatest/parameters/iterations > echo 1 > /sys/module/dmatest/parameters/max_channels > > Prior to this patch: ~1.3 GB/s > After this patch: ~1.8 GB/s > with 1 byte alignment: ~1.7 GB/s > > The patches are on top of the AM64 support series: > https://lore.kernel.org/lkml/20201208090440.31792-1-peter.ujfalusi@xxxxxx/ FWIW, tested this series with PCIe RC<->EP (using pcitest utility) Without this series READ => Size: 67108864 bytes DMA: YES Time: 0.137854270 seconds Rate: 475400 KB/s WRITE => Size: 67108864 bytes DMA: YES Time: 0.049701495 seconds Rate: 1318592 KB/s With this series READ => Size: 67108864 bytes DMA: YES Time: 0.045611175 seconds Rate: 1436840 KB/s WRITE => Size: 67108864 bytes DMA: YES Time: 0.042737440 seconds Rate: 1533456 KB/s Tested-by: Kishon Vijay Abraham I <kishon@xxxxxx> Thanks Kishon
