android_kernel_motorola_sm6225/drivers/mmc
Ulf Hansson 859dd55d91 ARM: 7215/1: mmc: mmci: Increase max_segs from 16 to 128
A significant increase (10-20%) in performance throughput for
USB mass storage is the reason for incrementing the value.
By some reason the USB driver allocates buffers which requires
a scattergather list to contain a lot more than 16 elements to
get optimal performance. This change sets the maximum elements
to 128.

Tests with large reads and large writes (100 MiB) show that the
throughput increase is significant for write (10% for this test)
but not for read. Tests are run on a Linux host with ext4 FS on
the gadget mass storage device. The sg-len still exceeds 16 for
the read tests but the performance gain is low or nothing.

Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Per Forlin <per.forlin@stericsson.com>
Signed-off-by: Ulf Hansson <ulf.hansson@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-01-20 00:00:54 +00:00
..
card MMC highlights for 3.3: 2012-01-13 20:41:15 -08:00
core Autogenerated GPG tag for Rusty D1ADB8F1: 15EE 8D6C AB0E 7F0C F999 BFCB D920 0E6C D1AD B8F1 2012-01-14 12:32:16 -08:00
host ARM: 7215/1: mmc: mmci: Increase max_segs from 16 to 128 2012-01-20 00:00:54 +00:00
Kconfig mmc: explicitly mention SDIO support in Kconfig 2008-10-12 11:04:36 +02:00
Makefile mmc: sdhci-pci: add platform data 2012-01-11 23:58:47 -05:00