Suganath Prabu S 787f2448c2 scsi: mpt3sas: Use firmware recommended queue depth ...

Currently, the mpt3sas driver sets the default queue depth based on the
physical interface of the attached device:

 - SAS : 254
 - SATA:  32
 - NVMe: 128

The IOC firmware provides a recommended queue depth for each device through
SAS IO Unit Page1 for SAS/SATA and PCIe IO Unit Page 1 for NVMe devices.

If the host sets the queue depth greater than the firmware recommended
value, then the IOC places the I/Os above the recommended queue depth in an
internal pending queue. This consumes outstanding host-credit/resources,
thereby leading to potential starvation of other devices.

To avoid this, use the device depth recommended by the IOC firmware.

Link: https://lore.kernel.org/r/20210809072639.21228-2-suganath-prabu.subramani@broadcom.com
Signed-off-by: Suganath Prabu S <suganath-prabu.subramani@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

2021-08-09 23:07:04 -04:00

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