Hi Adrian,
On 6/29/2016 6:54 PM, Adrian Hunter wrote:
Hi
Here is an updated version of the Software Command Queuing patches,
re-based on the SDHCI patches that I have.
Ulf, there are a lot of patches now and I think it would be worth taking
some of them. For example, the first 25 affect SDHCI only. If you accept
the "Command during Transfer" API introduced in patch 26, then you could
take patches 26-30 as well.
Are these patches affecting anything w.r.t. SW/HW CMDQ solution?
Although not yet gone through in detail.
But otherwise do you think it will be worthwhile to check both the
solutions before merging any particular design to upstream?
Well actually as you are aware of, HW CMDQ solution separate out itself
from legacy w.r.t. pulling/issuing/completing of reqs.
So mostly it should not affect much here w.r.t. SW CMDQ, but it will be
good if we could consider, how both solution will look into upstream
going forward.
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.
Agree.
I haven't had a chance to go through the hardware Command Queuing patches
in detail yet, but otherwise these patches are ready to go.
Request you to kindly review HW CMDQ patches as well before we plan to
merge both of them to upstream?
We do as well plan to go through SW CMDQ set of patches.
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 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 - 30. 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
31 - 38 make preparations for an arbitrary sized queue. Patches 39 - 42
introduce Command Queue definitions and helpers. Patches 43 - 49
complete the job of making the block driver use a queue. Patches 50 - 52
finally add Software Command Queuing, and 53 - 54 enable it for Intel eMMC
controllers. Most of the Software Command Queuing functionality is added
in patch 51.
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 (54):
mmc: sdhci: Do not call implementations of mmc host ops directly
mmc: sdhci: Split sdhci_add_host()
mmc: sdhci: Make signal voltage support explicit
mmc: sdhci: Tidy caps variables in sdhci_setup_host()
mmc: sdhci: Add sdhci_read_caps()
mmc: sdhci-pci: Do not runtime suspend at the end of sdhci_pci_probe()
mmc: sdhci: Move busy signal handling into sdhci_finish_cmd()
mmc: sdhci: Get rid of redundant BUG_ONs
mmc: sdhci: Simplify sdhci_finish_command() by clearing host->cmd at the start
mmc: sdhci: Record what command is using the data lines
mmc: sdhci: Get rid of host->busy_handle
mmc: sdhci: Reduce the use of host->mrq
mmc: sdhci: Move host->data warning
mmc: sdhci: Factor out sdhci_finish_mrq()
mmc: sdhci: Factor out sdhci_needs_reset()
mmc: sdhci: Track whether a reset is pending
mmc: sdhci: Clear pointers when a request finishes
mmc: sdhci: Ensure all requests get errored out
mmc: sdhci: Factor out sdhci_data_line_cmd()
mmc: sdhci: Separate timer timeout for command and data requests
mmc: sdhci: Allow for finishing multiple requests
mmc: sdhci: Factor out sdhci_auto_cmd12()
mmc: sdhci: Do not reset cmd or data circuits that are in use
mmc: sdhci: Avoid STOP cmd triggering warning in sdhci_send_command()
mmc: sdhci: sdhci_execute_tuning() must delete timer
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: 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
drivers/mmc/card/block.c | 738 +++++++++++++++++++++++++++++++++++---
drivers/mmc/card/mmc_test.c | 321 +++++++++++++++++
drivers/mmc/card/queue.c | 296 +++++++++------
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 | 8 +-
drivers/mmc/host/sdhci.c | 602 +++++++++++++++++++++----------
drivers/mmc/host/sdhci.h | 26 +-
include/linux/mmc/card.h | 5 +
include/linux/mmc/core.h | 12 +
include/linux/mmc/host.h | 9 +-
include/linux/mmc/mmc.h | 17 +
17 files changed, 1853 insertions(+), 399 deletions(-)
Regards
Adrian
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