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| author | Avri Altman <avri.altman@wdc.com> | 2024-05-30 16:25:07 +0200 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2024-05-31 02:34:38 +0200 |
| commit | 9ec54934ce857065e38523a2010e20182e76f515 (patch) | |
| tree | c2895352ebdb62596722f0aaaf7f8a84027a88bb /include/ufs/ufshci.h | |
| parent | Linux 6.10-rc1 (diff) | |
| download | linux-9ec54934ce857065e38523a2010e20182e76f515.tar.xz linux-9ec54934ce857065e38523a2010e20182e76f515.zip | |
scsi: ufs: core: Allow RTT negotiation
The rtt-upiu packets precede any data-out upiu packets, thus synchronizing
the data input to the device: this mostly applies to write operations, but
there are other operations that requires rtt as well.
There are several rules binding this rtt - data-out dialog, specifically
There can be at most outstanding bMaxNumOfRTT such packets. This might
have an effect on write performance (sequential write in particular), as
each data-out upiu must wait for its rtt sibling.
UFSHCI expects bMaxNumOfRTT to be min(bDeviceRTTCap, NORTT). However, as of
today, there does not appears to be no-one who sets it: not the host
controller nor the driver. It wasn't an issue up to now: bMaxNumOfRTT is
set to 2 after manufacturing, and wasn't limiting the write performance.
UFS4.0, and specifically gear 5 changes this, and requires the device to be
more attentive. This doesn't come free - the device has to allocate more
resources to that end, but the sequential write performance improvement is
significant. Early measurements shows 25% gain when moving from rtt 2 to
9. Therefore, set bMaxNumOfRTT to be min(bDeviceRTTCap, NORTT) as UFSHCI
expects.
Signed-off-by: Avri Altman <avri.altman@wdc.com>
Link: https://lore.kernel.org/r/20240530142510.734-2-avri.altman@wdc.com
Reviewed-by: Bean Huo <beanhuo@micron.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'include/ufs/ufshci.h')
| -rw-r--r-- | include/ufs/ufshci.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/ufs/ufshci.h b/include/ufs/ufshci.h index 385e1c6b8d60..c50f92bf2e1d 100644 --- a/include/ufs/ufshci.h +++ b/include/ufs/ufshci.h @@ -68,6 +68,7 @@ enum { /* Controller capability masks */ enum { MASK_TRANSFER_REQUESTS_SLOTS = 0x0000001F, + MASK_NUMBER_OUTSTANDING_RTT = 0x0000FF00, MASK_TASK_MANAGEMENT_REQUEST_SLOTS = 0x00070000, MASK_EHSLUTRD_SUPPORTED = 0x00400000, MASK_AUTO_HIBERN8_SUPPORT = 0x00800000, |