Hello,
Seems community already have some implementation for the eMMC5.1 device command
queue feature, but that require the eMMC host controller to support CMDQ. In my
platform, I don't have this kind of eMMC host controller but I have a
Samsung eMMC5.1 device which can support the Command queue.
With this limitation, I have to let eMMC host controller to manually send the
CMD44/45/13/46/47. So in this way, more commands are needed for an I/O request,
more interrupts/schedule are needed in driver.
Even this way have some more software overhead, but it can still use the eMMC5.1
device Command queue feature. After test with the iozone command:
"iozone -zec -t 4 -i0 -i2 -F iozonefile1 iozonefile2 iozonefile3 iozonefile4 -+n
-I -r 4k -s 500m -O -R -+r -+D" to test random performance, I saw a performance
improvment for random read on my eMMC5.1 device:
Random read
SW CMDQ: 5544.6
Normal Read: 3993.05
So I want to send this serial patches as RFC patch for reviewing
Chuanxiao Dong (5):
mmc: replace sbc to precmd and add postcmd
mmc: host: add runtime PM for host class dev
mmc: queue: change mqrq_cur and mqrq_pre to mq qdepth
mmc: core: add support for CMDQ feature in MMC Core stack
mmc: sdhci: add SW CMDQ support for CHT SDHCI host
drivers/mmc/card/block.c | 538 ++++++++++++++++++++++++++++++++++++++---
drivers/mmc/card/queue.c | 213 ++++++++--------
drivers/mmc/card/queue.h | 14 +-
drivers/mmc/core/core.c | 78 +++++-
drivers/mmc/core/host.c | 14 ++
drivers/mmc/core/mmc.c | 43 +++-
drivers/mmc/host/dw_mmc.c | 8 +-
drivers/mmc/host/mmci.c | 14 +-
drivers/mmc/host/omap_hsmmc.c | 18 +-
drivers/mmc/host/sdhci-acpi.c | 1 -
drivers/mmc/host/sdhci-pci.c | 1 -
drivers/mmc/host/sdhci.c | 137 +++++++++--
include/linux/mmc/card.h | 3 +
include/linux/mmc/core.h | 5 +-
include/linux/mmc/host.h | 5 +
include/linux/mmc/mmc.h | 21 ++
include/linux/mmc/pm.h | 1 +
include/linux/mmc/sdhci.h | 1 +
18 files changed, 909 insertions(+), 206 deletions(-)
--
1.7.10.4
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