svn commit: r228939 - head/sys/dev/mps

[Garrett Cooper]

2012/1/9 Alexander Motin <mav at freebsd.org>:
> On 09.01.2012 20:54, Maksim Yevmenkin wrote:
>>
>> On Wed, Dec 28, 2011 at 2:49 PM, Alexander Motin<mav at freebsd.org>  wrote:
>>
>>> Author: mav
>>> Date: Wed Dec 28 22:49:28 2011
>>> New Revision: 228939
>>> URL: http://svn.freebsd.org/changeset/base/228939
>>>
>>> Log:
>>>  Set maximum I/O size for mps(4) to MAXPHYS. Looking into the code, I see
>>>  no reason why it should be limited to 64K of DFLTPHYS. DMA data tag is
>>> any
>>>  way set to allow MAXPHYS, S/G lists (chain elements) are sufficient and
>>>  overflows are also handled. On my tests even 1MB I/Os are working fine.
>>>
>>>  Reviewed by:  ken@
>>>
>>> Modified:
>>>  head/sys/dev/mps/mps_sas.c
>>>
>>> Modified: head/sys/dev/mps/mps_sas.c
>>>
>>> ==============================================================================
>>> --- head/sys/dev/mps/mps_sas.c  Wed Dec 28 22:18:53 2011        (r228938)
>>> +++ head/sys/dev/mps/mps_sas.c  Wed Dec 28 22:49:28 2011        (r228939)
>>> @@ -937,6 +937,7 @@ mpssas_action(struct cam_sim *sim, union
>>>                cpi->transport_version = 0;
>>>                cpi->protocol = PROTO_SCSI;
>>>                cpi->protocol_version = SCSI_REV_SPC;
>>> +               cpi->maxio = MAXPHYS;
>>>                cpi->ccb_h.status = CAM_REQ_CMP;
>>>                break;
>>>        }
>>
>>
>> sorry for the late reply, but can we make in into tunable please? i
>> have in local tree
>>
>> --- mps_sas.c.orig      2011-11-17 02:05:04.000000000 -0800
>> +++ mps_sas.c   2011-12-28 16:05:10.000000000 -0800
>> @@ -121,6 +121,11 @@
>>
>>  MALLOC_DEFINE(M_MPSSAS, "MPSSAS", "MPS SAS memory");
>>
>> +int mps_maxio = MAXPHYS;
>> +TUNABLE_INT("hw.mps.maxio",&mps_maxio);
>> +SYSCTL_INT(_hw_mps, OID_AUTO, maxio, CTLFLAG_RD,&mps_maxio, 0,
>> +       "CAM maxio override\n");
>> +
>>  static __inline int mpssas_set_lun(uint8_t *lun, u_int ccblun);
>>  static struct mpssas_target * mpssas_alloc_target(struct mpssas_softc *,
>>      struct mpssas_target *);
>> @@ -938,6 +943,7 @@
>>
>>                cpi->protocol = PROTO_SCSI;
>>                cpi->protocol_version = SCSI_REV_SPC;
>>                cpi->ccb_h.status = CAM_REQ_CMP;
>> +               cpi->maxio = mps_maxio;
>>                break;
>>        }
>>        case XPT_GET_TRAN_SETTINGS:
>
>
> We can. but could you explain why? Have you found any problems this change?

    It would make it nice when dealing with different controllers -- a
similar example is that mfi(4) has a tunable called hw.mfi.max_cmds
which controls the I/O command queue size as not all MegaRAID cards
have the same I/O queue size capabilities.
Thanks,
-Garrett