On Mon, May 6, 2024 at 3:17 PM Miquel Raynal <miquel.raynal@xxxxxxxxxxx> wrote: > > Hi, > > devnull+keguang.zhang.gmail.com@xxxxxxxxxx wrote on Tue, 30 Apr 2024 > 19:11:11 +0800: > > > From: Keguang Zhang <keguang.zhang@xxxxxxxxx> > > > > nand_read_subpage() reads data and ECC data by two separate > > operations. > > This patch allows the NAND controllers who support > > monolithic page read to do subpage read by a single operation, > > which is more effective than nand_read_subpage(). > > I am a bit puzzled by this change. Usually nand_read_subpage is used > for optimizations (when less data than a full page must be retrieved). > I know it may be used in other cases (because it's easier for the core > in order to support a wide range of controllers). Can you please show a > speed test showing the results before I consider merging this patch? > With this patch: # flash_speed -c 128 -d /dev/mtd1 scanning for bad eraseblocks scanned 128 eraseblocks, 0 are bad testing eraseblock write speed eraseblock write speed is 2112 KiB/s testing eraseblock read speed eraseblock read speed is 3454 KiB/s testing page write speed page write speed is 1915 KiB/s testing page read speed page read speed is 2999 KiB/s testing 2 page write speed 2 page write speed is 2000 KiB/s testing 2 page read speed 2 page read speed is 3207 KiB/s Testing erase speed erase speed is 72495 KiB/s Testing 2x multi-block erase speed 2x multi-block erase speed is 74135 KiB/s Testing 4x multi-block erase speed 4x multi-block erase speed is 74812 KiB/s Testing 8x multi-block erase speed 8x multi-block erase speed is 75502 KiB/s Testing 16x multi-block erase speed 16x multi-block erase speed is 75851 KiB/s Testing 32x multi-block erase speed 32x multi-block erase speed is 75851 KiB/s Testing 64x multi-block erase speed 64x multi-block erase speed is 76204 KiB/s finished Without this patch: # flash_speed -c 128 -d /dev/mtd1 scanning for bad eraseblocks scanned 128 eraseblocks, 0 are bad testing eraseblock write speed eraseblock write speed is 2074 KiB/s testing eraseblock read speed eraseblock read speed is 2895 KiB/s testing page write speed page write speed is 998 KiB/s testing page read speed page read speed is 1499 KiB/s testing 2 page write speed 2 page write speed is 1002 KiB/s testing 2 page read speed 2 page read speed is 1554 KiB/s Testing erase speed erase speed is 76560 KiB/s Testing 2x multi-block erase speed 2x multi-block erase speed is 74019 KiB/s Testing 4x multi-block erase speed 4x multi-block erase speed is 74769 KiB/s Testing 8x multi-block erase speed 8x multi-block erase speed is 75149 KiB/s Testing 16x multi-block erase speed 16x multi-block erase speed is 75921 KiB/s Testing 32x multi-block erase speed 32x multi-block erase speed is 75921 KiB/s Testing 64x multi-block erase speed 64x multi-block erase speed is 75921 KiB/s finished The throughput of the former is twice that of the latter. > The monolithic thing was not supposed to improve throughput but to help > with very limited controllers. > > Thanks, > Miquèl -- Best regards, Keguang Zhang
