On 5/13/19 8:24 AM, Uenal Mutlu wrote: > Increasing the SATA/AHCI DMA TX/RX FIFOs (P0DMACR.TXTS and .RXTS, ie. > TX_TRANSACTION_SIZE and RX_TRANSACTION_SIZE) from default 0x0 each > to 0x3 each, gives a write performance boost of 120 MiB/s to 132 MiB/s > from lame 36 MiB/s to 45 MiB/s previously. > Read performance is above 200 MiB/s. > [tested on SSD using dd bs=4K/8K/12K/16K/20K/24K/32K: peak-perf at 12K] > > Tested on the SBCs Banana Pi R1 (aka Lamobo R1) and Banana Pi M1 which > are based on the Allwinner A20 32bit-SoC (ARMv7-a / arm-linux-gnueabihf). > These devices are RaspberryPi-like small devices. > > This problem of slow SATA write-speed with these small devices lasts > for about 7 years now (beginning with the A10 SoC). Many commentators > throughout the years wrongly assumed the slow write speed was a > hardware limitation. This patch finally solves the problem, which > in fact was just a hard-to-find software problem due to lack of > SATA/AHCI documentation by the SoC-maker Allwinner Technology. > > Lists of the affected sunxi and other boards and SoCs with SATA using > the ahci_sunxi driver: > $ grep -i -e "^&ahci" arch/arm/boot/dts/sun*dts > and http://linux-sunxi.org/SATA#Devices_with_SATA_ports > See also http://linux-sunxi.org/Category:Devices_with_SATA_port Applied for 5.3, thanks. -- Jens Axboe
