On Wed, 12 Feb 2020 at 05:14, Baolin Wang <baolin.wang7@xxxxxxxxx> 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 64 > to allow more requests can be be prepared, merged and inserted into IO > scheduler, but we only allow 2 requests in flight, that is enough to let > the irq handler always trigger the next request without a context switch, > 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=1G --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 5 times for each case and output a average speed. > > 1) Sequential read: > Speed: 59.4MiB/s, 63.4MiB/s, 57.5MiB/s, 57.2MiB/s, 60.8MiB/s > Average speed: 59.66MiB/s > > 2) Random read: > Speed: 26.9MiB/s, 26.9MiB/s, 27.1MiB/s, 27.1MiB/s, 27.2MiB/s > Average speed: 27.04MiB/s > > 3) Sequential write: > Speed: 71.6MiB/s, 72.5MiB/s, 72.2MiB/s, 64.6MiB/s, 67.5MiB/s > Average speed: 69.68MiB/s > > 4) Random write: > Speed: 36.3MiB/s, 35.4MiB/s, 38.6MiB/s, 34MiB/s, 35.5MiB/s > Average speed: 35.96MiB/s > > 2. With MMC software queue > I tested 5 times for each case and output a average speed. > > 1) Sequential read: > Speed: 59.2MiB/s, 60.4MiB/s, 63.6MiB/s, 60.3MiB/s, 59.9MiB/s > Average speed: 60.68MiB/s > > 2) Random read: > Speed: 31.3MiB/s, 31.4MiB/s, 31.5MiB/s, 31.3MiB/s, 31.3MiB/s > Average speed: 31.36MiB/s > > 3) Sequential write: > Speed: 71MiB/s, 71.8MiB/s, 72.3MiB/s, 72.2MiB/s, 71MiB/s > Average speed: 71.66MiB/s > > 4) Random write: > Speed: 68.9MiB/s, 68.7MiB/s, 68.8MiB/s, 68.6MiB/s, 68.8MiB/s > Average speed: 68.76MiB/s > > Form above data, we can see the MMC software queue can help to improve some > performance obviously for random read and write, though no obvious improvement > for sequential read and write. > > Any comments are welcome. Thanks a lot. > > Changes from v8: > - Add more description in the commit message. > - Optimize the failure log when calling cqe_enable(). > > Changes from v7: > - Add reviewed tag from Arnd. > - Use the 'hsq' acronym for varibles and functions in the core layer. > - Check the 'card->ext_csd.cmdq_en' in cqhci.c to make sure the CQE > can work normally. > - Add a new patch to enable the host software queue for the SD card. > - Use the default MMC queue depth for host software queue. > > Changes from v6: > - Change the patch order and set host->always_defer_done = true for the > Spreadtrum host driver. > > Changes from v5: > - Modify the condition of defering to complete request suggested by Adrian. > > Changes from v4: > - Add a seperate patch to introduce a variable to defer to complete > data requests for some host drivers, when using host software queue. > > Changes from v3: > - Use host software queue instead of sqhci. > - Fix random config building issue. > - Change queue depth to 32, but still only allow 2 requests in flight. > - Update the testing data. > > 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. > > Baolin Wang (5): > mmc: Add MMC host software queue support > mmc: core: Enable the MMC host software queue for the SD card > mmc: host: sdhci: Add request_done ops for struct sdhci_ops > mmc: host: sdhci: Add a variable to defer to complete requests if > needed > mmc: host: sdhci-sprd: Add software queue support > > drivers/mmc/core/block.c | 61 ++++++++ > drivers/mmc/core/mmc.c | 18 ++- > drivers/mmc/core/queue.c | 22 ++- > drivers/mmc/core/sd.c | 10 ++ > drivers/mmc/host/Kconfig | 8 + > drivers/mmc/host/Makefile | 1 + > drivers/mmc/host/cqhci.c | 8 +- > drivers/mmc/host/mmc_hsq.c | 343 +++++++++++++++++++++++++++++++++++++++++ > drivers/mmc/host/mmc_hsq.h | 30 ++++ > drivers/mmc/host/sdhci-sprd.c | 28 ++++ > drivers/mmc/host/sdhci.c | 14 +- > drivers/mmc/host/sdhci.h | 3 + > include/linux/mmc/host.h | 3 + > 13 files changed, 534 insertions(+), 15 deletions(-) > create mode 100644 drivers/mmc/host/mmc_hsq.c > create mode 100644 drivers/mmc/host/mmc_hsq.h > > -- > 1.7.9.5 > Applied for next, thanks! Also, thanks for your patience while moving forward during the reviews! Note, I did some amending of patch1 to resolve some checkpatch warnings. SPDX licence and Kconfig help texts, please have a look and tell if there are something that doesn't look good. Kind regards Uffe
