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 -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
