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Date:      Mon, 9 Jan 2012 11:01:54 -0800
From:      Maksim Yevmenkin <emax@freebsd.org>
To:        Alexander Motin <mav@freebsd.org>
Cc:        svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org
Subject:   Re: svn commit: r228939 - head/sys/dev/mps
Message-ID:  <CAFPOs6rF1iSDMPdaXCbC_QXsEmqF5iqN3ZNcJkg5AFj15kmGCA@mail.gmail.com>
In-Reply-To: <4F0B38B9.1020302@FreeBSD.org>
References:  <201112282249.pBSMnTZu028304@svn.freebsd.org> <CAFPOs6oaMNsHP9VFtL-Szs=vDQj-Ss=JKCECqsUNTMXi7UwNHw@mail.gmail.com> <4F0B38B9.1020302@FreeBSD.org>

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2012/1/9 Alexander Motin <mav@freebsd.org>:
> On 09.01.2012 20:54, Maksim Yevmenkin wrote:
>>
>> On Wed, Dec 28, 2011 at 2:49 PM, Alexander Motin<mav@freebsd.org> =A0wro=
te:
>>>
>>> Author: mav
>>> Date: Wed Dec 28 22:49:28 2011
>>> New Revision: 228939
>>> URL: http://svn.freebsd.org/changeset/base/228939
>>>
>>> Log:
>>> =A0Set maximum I/O size for mps(4) to MAXPHYS. Looking into the code, I=
 see
>>> =A0no reason why it should be limited to 64K of DFLTPHYS. DMA data tag =
is
>>> any
>>> =A0way set to allow MAXPHYS, S/G lists (chain elements) are sufficient =
and
>>> =A0overflows are also handled. On my tests even 1MB I/Os are working fi=
ne.
>>>
>>> =A0Reviewed by: =A0ken@
>>>
>>> Modified:
>>> =A0head/sys/dev/mps/mps_sas.c
>>>
>>> Modified: head/sys/dev/mps/mps_sas.c
>>>
>>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D
>>> --- head/sys/dev/mps/mps_sas.c =A0Wed Dec 28 22:18:53 2011 =A0 =A0 =A0 =
=A0(r228938)
>>> +++ head/sys/dev/mps/mps_sas.c =A0Wed Dec 28 22:49:28 2011 =A0 =A0 =A0 =
=A0(r228939)
>>> @@ -937,6 +937,7 @@ mpssas_action(struct cam_sim *sim, union
>>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0cpi->transport_version =3D 0;
>>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0cpi->protocol =3D PROTO_SCSI;
>>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0cpi->protocol_version =3D SCSI_REV_SPC;
>>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 cpi->maxio =3D MAXPHYS;
>>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0cpi->ccb_h.status =3D CAM_REQ_CMP;
>>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0break;
>>> =A0 =A0 =A0 =A0}
>>
>>
>> sorry for the late reply, but can we make in into tunable please? i
>> have in local tree
>>
>> --- mps_sas.c.orig =A0 =A0 =A02011-11-17 02:05:04.000000000 -0800
>> +++ mps_sas.c =A0 2011-12-28 16:05:10.000000000 -0800
>> @@ -121,6 +121,11 @@
>>
>> =A0MALLOC_DEFINE(M_MPSSAS, "MPSSAS", "MPS SAS memory");
>>
>> +int mps_maxio =3D MAXPHYS;
>> +TUNABLE_INT("hw.mps.maxio",&mps_maxio);
>> +SYSCTL_INT(_hw_mps, OID_AUTO, maxio, CTLFLAG_RD,&mps_maxio, 0,
>>
>> + =A0 =A0 =A0 "CAM maxio override\n");
>> +
>> =A0static __inline int mpssas_set_lun(uint8_t *lun, u_int ccblun);
>> =A0static struct mpssas_target * mpssas_alloc_target(struct mpssas_softc=
 *,
>> =A0 =A0 =A0struct mpssas_target *);
>> @@ -938,6 +943,7 @@
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0cpi->protocol =3D PROTO_SCSI;
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0cpi->protocol_version =3D SCSI_REV_SPC;
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0cpi->ccb_h.status =3D CAM_REQ_CMP;
>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 cpi->maxio =3D mps_maxio;
>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0break;
>> =A0 =A0 =A0 =A0}
>> =A0 =A0 =A0 =A0case XPT_GET_TRAN_SETTINGS:
>
>
> We can. but could you explain why? Have you found any problems this chang=
e?

not really. i've had this patch in the local tree for a while now. we
are experimenting with various MAXPHYS/maxio settings and having this
tunable is very handy. basically, we can set MAXPHYS to some larger
value and tweak maxio (for testing purposes) without
recompiling/installing new kernel.

thanks,
max



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