Hi Here is an updated version of the Software Command Queuing patches, re-based on next, with patches 1-5 dropped because they have been applied, and 2 fixes that have been rolled in (refer Changes in V5 below). Performance results: Results can vary from run to run, but here are some results showing 1, 2 or 4 processes with 4k and 32k record sizes. They show up to 40% improvement in read performance when there are multiple processes. iozone -s 8192k -r 4k -i 0 -i 1 -i 2 -i 8 -I -t 1 -F /mnt/mmc/iozone1.tmp Children see throughput for 1 initial writers = 27909.87 kB/sec 24204.14 kB/sec -13.28 % Children see throughput for 1 rewriters = 28839.28 kB/sec 25531.92 kB/sec -11.47 % Children see throughput for 1 readers = 25889.65 kB/sec 24883.23 kB/sec -3.89 % Children see throughput for 1 re-readers = 25558.23 kB/sec 24679.89 kB/sec -3.44 % Children see throughput for 1 random readers = 25571.48 kB/sec 24689.52 kB/sec -3.45 % Children see throughput for 1 mixed workload = 25758.59 kB/sec 24487.52 kB/sec -4.93 % Children see throughput for 1 random writers = 24787.51 kB/sec 19368.99 kB/sec -21.86 % iozone -s 8192k -r 32k -i 0 -i 1 -i 2 -i 8 -I -t 1 -F /mnt/mmc/iozone1.tmp Children see throughput for 1 initial writers = 91344.61 kB/sec 102008.56 kB/sec 11.67 % Children see throughput for 1 rewriters = 87932.36 kB/sec 96630.44 kB/sec 9.89 % Children see throughput for 1 readers = 134879.82 kB/sec 110292.79 kB/sec -18.23 % Children see throughput for 1 re-readers = 147632.13 kB/sec 109053.33 kB/sec -26.13 % Children see throughput for 1 random readers = 93547.37 kB/sec 112225.50 kB/sec 19.97 % Children see throughput for 1 mixed workload = 93560.04 kB/sec 110515.21 kB/sec 18.12 % Children see throughput for 1 random writers = 92841.84 kB/sec 81153.81 kB/sec -12.59 % iozone -s 8192k -r 4k -i 0 -i 1 -i 2 -i 8 -I -t 2 -F /mnt/mmc/iozone1.tmp /mnt/mmc/iozone2.tmp Children see throughput for 2 initial writers = 31145.43 kB/sec 33771.25 kB/sec 8.43 % Children see throughput for 2 rewriters = 30592.57 kB/sec 35916.46 kB/sec 17.40 % Children see throughput for 2 readers = 31669.83 kB/sec 37460.13 kB/sec 18.28 % Children see throughput for 2 re-readers = 32079.94 kB/sec 37373.33 kB/sec 16.50 % Children see throughput for 2 random readers = 27731.19 kB/sec 37601.65 kB/sec 35.59 % Children see throughput for 2 mixed workload = 13927.50 kB/sec 14617.06 kB/sec 4.95 % Children see throughput for 2 random writers = 31250.00 kB/sec 33106.72 kB/sec 5.94 % iozone -s 8192k -r 32k -i 0 -i 1 -i 2 -i 8 -I -t 2 -F /mnt/mmc/iozone1.tmp /mnt/mmc/iozone2.tmp Children see throughput for 2 initial writers = 123255.84 kB/sec 131252.22 kB/sec 6.49 % Children see throughput for 2 rewriters = 115234.91 kB/sec 107225.74 kB/sec -6.95 % Children see throughput for 2 readers = 128921.86 kB/sec 148562.71 kB/sec 15.23 % Children see throughput for 2 re-readers = 127815.24 kB/sec 149304.32 kB/sec 16.81 % Children see throughput for 2 random readers = 125600.46 kB/sec 148406.56 kB/sec 18.16 % Children see throughput for 2 mixed workload = 44006.94 kB/sec 50937.36 kB/sec 15.75 % Children see throughput for 2 random writers = 120623.95 kB/sec 103969.05 kB/sec -13.81 % iozone -s 8192k -r 4k -i 0 -i 1 -i 2 -i 8 -I -t 4 -F /mnt/mmc/iozone1.tmp /mnt/mmc/iozone2.tmp /mnt/mmc/iozone3.tmp /mnt/mmc/iozone4.tmp Children see throughput for 4 initial writers = 24100.96 kB/sec 33336.58 kB/sec 38.32 % Children see throughput for 4 rewriters = 31650.20 kB/sec 33091.53 kB/sec 4.55 % Children see throughput for 4 readers = 33276.92 kB/sec 41799.89 kB/sec 25.61 % Children see throughput for 4 re-readers = 31786.96 kB/sec 41501.74 kB/sec 30.56 % Children see throughput for 4 random readers = 31991.65 kB/sec 40973.93 kB/sec 28.08 % Children see throughput for 4 mixed workload = 15804.80 kB/sec 13581.32 kB/sec -14.07 % Children see throughput for 4 random writers = 31231.42 kB/sec 34537.03 kB/sec 10.58 % iozone -s 8192k -r 32k -i 0 -i 1 -i 2 -i 8 -I -t 4 -F /mnt/mmc/iozone1.tmp /mnt/mmc/iozone2.tmp /mnt/mmc/iozone3.tmp /mnt/mmc/iozone4.tmp Children see throughput for 4 initial writers = 116567.42 kB/sec 119280.35 kB/sec 2.33 % Children see throughput for 4 rewriters = 115010.96 kB/sec 120864.34 kB/sec 5.09 % Children see throughput for 4 readers = 130700.29 kB/sec 177834.21 kB/sec 36.06 % Children see throughput for 4 re-readers = 125392.58 kB/sec 175975.28 kB/sec 40.34 % Children see throughput for 4 random readers = 132194.57 kB/sec 176630.46 kB/sec 33.61 % Children see throughput for 4 mixed workload = 56464.98 kB/sec 54140.61 kB/sec -4.12 % Children see throughput for 4 random writers = 109128.36 kB/sec 85359.80 kB/sec -21.78 % The current block driver supports 2 requests on the go at a time. Patches 1 - 8 make preparations for an arbitrary sized queue. Patches 9 - 12 introduce Command Queue definitions and helpers. Patches 13 - 19 complete the job of making the block driver use a queue. Patches 20 - 23 finally add Software Command Queuing, and 24 - 25 enable it for Intel eMMC controllers. Most of the Software Command Queuing functionality is added in patch 22. As noted below, the patches can also be found here: http://git.infradead.org/users/ahunter/linux-sdhci.git/shortlog/refs/heads/swcmdq Changes in V5: Patches 1-5 dropped because they have been applied. Re-based on next. Fixed use of blk_end_request_cur() when it should have been blk_end_request_all() to error out requests during error recovery. Fixed unpaired retune_hold / retune_release in the error recovery path. Changes in V4: Re-based on next + v4.8-rc2 + "block: Fix secure erase" patch Changes in V3: Patches 1-25 dropped because they have been applied. Re-based on next. mmc: queue: Allocate queue of size qdepth Free queue during cleanup mmc: mmc: Add Command Queue definitions Add cmdq_en to mmc-dev-attrs.txt documentation mmc: queue: Share mmc request array between partitions New patch Changes in V2: Added 5 patches already sent here: http://marc.info/?l=linux-mmc&m=146712062816835 Added 3 more new patches: mmc: sdhci-pci: Do not runtime suspend at the end of sdhci_pci_probe() mmc: sdhci: Avoid STOP cmd triggering warning in sdhci_send_command() mmc: sdhci: sdhci_execute_tuning() must delete timer Carried forward the V2 fix to: mmc: mmc_test: Disable Command Queue while mmc_test is used Also reset the cmd circuit for data timeout if it is processing the data cmd, in patch: mmc: sdhci: Do not reset cmd or data circuits that are in use There wasn't much comment on the RFC so there have been few changes. Venu Byravarasu commented that it may be more efficient to use Software Command Queuing only when there is more than 1 request queued - it isn't obvious how well that would work in practice, but it could be added later if it could be shown to be beneficial. Original Cover Letter: Chuanxiao Dong sent some patches last year relating to eMMC 5.1 Software Command Queuing. He did not follow-up but I have contacted him and he says it is OK if I take over upstreaming the patches. eMMC Command Queuing is a feature added in version 5.1. The card maintains a queue of up to 32 data transfers. Commands CMD45/CMD45 are sent to queue up transfers in advance, and then one of the transfers is selected to "execute" by CMD46/CMD47 at which point data transfer actually begins. The advantage of command queuing is that the card can prepare for transfers in advance. That makes a big difference in the case of random reads because the card can start reading into its cache in advance. A v5.1 host controller can manage the command queue itself, but it is also possible for software to manage the queue using an non-v5.1 host controller - that is what Software Command Queuing is. Refer to the JEDEC (http://www.jedec.org/) eMMC v5.1 Specification for more information about Command Queuing. While these patches are heavily based on Dong's patches, there are some changes: SDHCI has been amended to support commands during transfer. That is a generic change added in patches 1 - 5. [Those patches have now been applied] In principle, that would also support SDIO's CMD52 during data transfer. The original approach added multiple commands into the same request for sending CMD44, CMD45 and CMD13. That is not strictly necessary and has been omitted for now. The original approach also called blk_end_request() from the mrq->done() function, which means the upper layers learnt of completed requests slightly earlier. That is not strictly related to Software Command Queuing and is something that could potentially be done for all data requests. That has been omitted for now. The current block driver supports 2 requests on the go at a time. Patches 1 - 8 make preparations for an arbitrary sized queue. Patches 9 - 12 introduce Command Queue definitions and helpers. Patches 13 - 19 complete the job of making the block driver use a queue. Patches 20 - 23 finally add Software Command Queuing, and 24 - 25 enable it for Intel eMMC controllers. Most of the Software Command Queuing functionality is added in patch 22. The patches can also be found here: http://git.infradead.org/users/ahunter/linux-sdhci.git/shortlog/refs/heads/swcmdq The patches have only had basic testing so far. Ad-hoc testing shows a degradation in sequential read performance of about 10% but an increase in throughput for mixed workload of multiple processes of about 90%. The reduction in sequential performance is due to the need to read the Queue Status register between each transfer. These patches should not conflict with Hardware Command Queuing which handles the queue in a completely different way and thus does not need to share code with Software Command Queuing. The exceptions being the Command Queue definitions and queue allocation which should be able to be used. Adrian Hunter (25): mmc: queue: Fix queue thread wake-up mmc: queue: Factor out mmc_queue_alloc_bounce_bufs() mmc: queue: Factor out mmc_queue_alloc_bounce_sgs() mmc: queue: Factor out mmc_queue_alloc_sgs() mmc: queue: Factor out mmc_queue_reqs_free_bufs() mmc: queue: Introduce queue depth mmc: queue: Use queue depth to allocate and free mmc: queue: Allocate queue of size qdepth mmc: mmc: Add Command Queue definitions mmc: mmc: Add functions to enable / disable the Command Queue mmc: mmc_test: Disable Command Queue while mmc_test is used mmc: block: Disable Command Queue while RPMB is used mmc: core: Do not prepare a new request twice mmc: core: Export mmc_retune_hold() and mmc_retune_release() mmc: block: Factor out mmc_blk_requeue() mmc: block: Fix 4K native sector check mmc: block: Use local var for mqrq_cur mmc: block: Pass mqrq to mmc_blk_prep_packed_list() mmc: block: Introduce queue semantics mmc: queue: Share mmc request array between partitions mmc: queue: Add a function to control wake-up on new requests mmc: block: Add Software Command Queuing mmc: mmc: Enable Software Command Queuing mmc: sdhci-pci: Enable Software Command Queuing for some Intel controllers mmc: sdhci-acpi: Enable Software Command Queuing for some Intel controllers Documentation/mmc/mmc-dev-attrs.txt | 1 + drivers/mmc/card/block.c | 738 +++++++++++++++++++++++++++++++++--- drivers/mmc/card/mmc_test.c | 13 + drivers/mmc/card/queue.c | 332 ++++++++++------ drivers/mmc/card/queue.h | 35 +- drivers/mmc/core/core.c | 18 +- drivers/mmc/core/host.c | 2 + drivers/mmc/core/host.h | 2 - drivers/mmc/core/mmc.c | 43 ++- drivers/mmc/core/mmc_ops.c | 27 ++ drivers/mmc/host/sdhci-acpi.c | 2 +- drivers/mmc/host/sdhci-pci-core.c | 2 +- include/linux/mmc/card.h | 9 + include/linux/mmc/core.h | 5 + include/linux/mmc/host.h | 4 +- include/linux/mmc/mmc.h | 17 + 16 files changed, 1046 insertions(+), 204 deletions(-) Regards Adrian -- 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
