On 09.01.2012 21:01, Maksim Yevmenkin wrote:
2012/1/9 Alexander Motin<m...@freebsd.org>:
On 09.01.2012 20:54, Maksim Yevmenkin wrote:
On Wed, Dec 28, 2011 at 2:49 PM, Alexander Motin<m...@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?
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.
I don't really think that it is perfect place for such tunable. It is a
bit strange IMHO to have different maxio for different types of HBAs
except physical limitations. I would prefer it to be configurable on
above layers, for example, file systems, if needed. But if you need it
here for something, I won't object against adding it.
Have you found any benefits of having maxio below MAXPHYS while
experimenting? May be those results could be used to improve FS behavior
somehow to make tuning not needed?
--
Alexander Motin
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