Hi Here is an updated version of the Software Command Queuing patches, re-based on next and with some changes - see Changes in V3. Ulf, as before, if you accept the "Command during Transfer" API introduced in patch 1, then you could take patches 1-5 in advance of the rest. I have begun going through the hardware Command Queuing patches. They are still some way from ready, and as a consequence I believe they should consider re-basing on top of these patches which are ready to go. I will go into more details when I reply to the hardware Command Queuing patches. As noted below, the patches can also be found here: http://git.infradead.org/users/ahunter/linux-sdhci.git/shortlog/refs/heads/swcmdq 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. 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 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. 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 6 - 13 make preparations for an arbitrary sized queue. Patches 14 - 17 introduce Command Queue definitions and helpers. Patches 18 - 24 complete the job of making the block driver use a queue. Patches 25 - 28 finally add Software Command Queuing, and 29 - 30 enable it for Intel eMMC controllers. Most of the Software Command Queuing functionality is added in patch 27. 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 (30): mmc: core: Add support for sending commands during data transfer mmc: mmc_test: Add tests for sending commands during transfer mmc: sdhci: Support cap_cmd_during_tfr requests mmc: sdhci-pci: Set MMC_CAP_CMD_DURING_TFR for Intel eMMC controllers mmc: sdhci-acpi: Set MMC_CAP_CMD_DURING_TFR for Intel eMMC controllers 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 | 740 +++++++++++++++++++++++++++++++++--- drivers/mmc/card/mmc_test.c | 321 ++++++++++++++++ drivers/mmc/card/queue.c | 332 ++++++++++------ drivers/mmc/card/queue.h | 27 +- drivers/mmc/core/core.c | 113 +++++- 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 | 4 +- drivers/mmc/host/sdhci-pci-core.c | 1 + drivers/mmc/host/sdhci.c | 21 +- include/linux/mmc/card.h | 9 + include/linux/mmc/core.h | 12 + include/linux/mmc/host.h | 9 +- include/linux/mmc/mmc.h | 17 + 17 files changed, 1476 insertions(+), 205 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
