RE: [PATCH v3] scsi: ufs: Increase the maximum data buffer size

Avri Altman
2022-07-27T05:06:46Z

> Measurements for one particular UFS controller + UFS device show a 25%
> higher read bandwidth if the maximum data buffer size is increased from
> 512 KiB to 1 MiB. Hence increase the maximum size of the data buffer
> associated with a single request from SCSI_DEFAULT_MAX_SECTORS (1024)
> * 512 bytes = 512 KiB to 1 MiB.
>
> Notes:
> - The maximum data buffer size supported by the UFSHCI specification
> is 65535 * 256 KiB or about 16 GiB.
> - The maximum data buffer size for READ(10) commands is 65535 logical
> blocks. To transfer more than 65535 * 4096 bytes = 255 MiB with a
> single SCSI command, the READ(16) command is required. Support for
> READ(16) is optional in the UFS 3.1 and UFS 4.0 standards.
>
> Cc: Adrian Hunter <adrian.hunter@intel.com>
> Cc: Avri Altman <avri.altman@wdc.com>
> Cc: Bean Huo <beanhuo@micron.com>
> Cc: Stanley Chu <stanley.chu@mediatek.com>
> Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: Avri Altman <avri.altman@wdc.com>
Tested-by: Avri Altman <avri.altman@wdc.com>