On 26/09/19 12:43 PM, Baolin Wang wrote: > Hi Adrian and Ulf, > > On Thu, 19 Sep 2019 at 13:59, Baolin Wang <baolin.wang@xxxxxxxxxx> wrote: >> >> Hi All, >> >> Now the MMC read/write stack will always wait for previous request is >> completed by mmc_blk_rw_wait(), before sending a new request to hardware, >> or queue a work to complete request, that will bring context switching >> overhead, especially for high I/O per second rates, to affect the IO >> performance. >> >> Thus this patch set will introduce the MMC software command queue support >> based on command queue engine's interfaces, and set the queue depth as 2, >> that means we do not need wait for previous request is completed and can >> queue 2 requests in flight. It is enough to let the irq handler always >> trigger the next request without a context switch and then ask the blk_mq >> layer for the next one to get queued, as well as avoiding a long latency. >> >> Moreover we can expand the MMC software queue interface to support >> MMC packed request or packed command instead of adding new interfaces, >> according to previosus discussion. >> >> Below are some comparison data with fio tool. The fio command I used >> is like below with changing the '--rw' parameter and enabling the direct >> IO flag to measure the actual hardware transfer speed in 4K block size. >> >> ./fio --filename=/dev/mmcblk0p30 --direct=1 --iodepth=20 --rw=read --bs=4K --size=512M --group_reporting --numjobs=20 --name=test_read >> >> My eMMC card working at HS400 Enhanced strobe mode: >> [ 2.229856] mmc0: new HS400 Enhanced strobe MMC card at address 0001 >> [ 2.237566] mmcblk0: mmc0:0001 HBG4a2 29.1 GiB >> [ 2.242621] mmcblk0boot0: mmc0:0001 HBG4a2 partition 1 4.00 MiB >> [ 2.249110] mmcblk0boot1: mmc0:0001 HBG4a2 partition 2 4.00 MiB >> [ 2.255307] mmcblk0rpmb: mmc0:0001 HBG4a2 partition 3 4.00 MiB, chardev (248:0) >> >> 1. Without MMC software queue >> I tested 3 times for each case and output a average speed. >> >> 1) Sequential read: >> Speed: 28.9MiB/s, 26.4MiB/s, 30.9MiB/s >> Average speed: 28.7MiB/s >> >> 2) Random read: >> Speed: 18.2MiB/s, 8.9MiB/s, 15.8MiB/s >> Average speed: 14.3MiB/s >> >> 3) Sequential write: >> Speed: 21.1MiB/s, 27.9MiB/s, 25MiB/s >> Average speed: 24.7MiB/s >> >> 4) Random write: >> Speed: 21.5MiB/s, 18.1MiB/s, 18.1MiB/s >> Average speed: 19.2MiB/s >> >> 2. With MMC software queue >> I tested 3 times for each case and output a average speed. >> >> 1) Sequential read: >> Speed: 44.1MiB/s, 42.3MiB/s, 44.4MiB/s >> Average speed: 43.6MiB/s >> >> 2) Random read: >> Speed: 30.6MiB/s, 30.9MiB/s, 30.5MiB/s >> Average speed: 30.6MiB/s >> >> 3) Sequential write: >> Speed: 44.1MiB/s, 45.9MiB/s, 44.2MiB/s >> Average speed: 44.7MiB/s >> >> 4) Random write: >> Speed: 45.1MiB/s, 43.3MiB/s, 42.4MiB/s >> Average speed: 43.6MiB/s >> >> Form above data, we can see the MMC software queue can help to improve the >> performance obviously. >> >> Any comments are welcome. Thanks a lot. >> >> Changes from v2: >> - Remove reference to 'struct cqhci_host' and 'struct cqhci_slot', >> instead adding 'struct sqhci_host', which is only used by software queue. >> >> Changes from v1: >> - Add request_done ops for sdhci_ops. >> - Replace virtual command queue with software queue for functions and >> variables. >> - Rename the software queue file and add sqhci.h header file. > > Do you have any comments for this patch set except the random config > building issue that will be fixed in the next version? Thanks. Pedantically, swhci is not a host controller interface, so the name still seems inappropriate. Otherwise I haven't had time to look at it, sorry. > >> >> Baolin Wang (3): >> mmc: Add MMC software queue support >> mmc: host: sdhci: Add request_done ops for struct sdhci_ops >> mmc: host: sdhci-sprd: Add software queue support >> >> drivers/mmc/core/block.c | 61 ++++++++ >> drivers/mmc/core/mmc.c | 13 +- >> drivers/mmc/core/queue.c | 25 ++- >> drivers/mmc/host/Kconfig | 9 ++ >> drivers/mmc/host/Makefile | 1 + >> drivers/mmc/host/sdhci-sprd.c | 26 ++++ >> drivers/mmc/host/sdhci.c | 12 +- >> drivers/mmc/host/sdhci.h | 2 + >> drivers/mmc/host/sqhci.c | 344 +++++++++++++++++++++++++++++++++++++++++ >> drivers/mmc/host/sqhci.h | 53 +++++++ >> include/linux/mmc/host.h | 3 + >> 11 files changed, 537 insertions(+), 12 deletions(-) >> create mode 100644 drivers/mmc/host/sqhci.c >> create mode 100644 drivers/mmc/host/sqhci.h >> >> -- >> 1.7.9.5 >> > >
