Messages in this thread Patch in this message |  | | Date | Wed, 30 Aug 2006 13:55:48 -0700 | | From | "Darrick J. Wong" <> | | Subject | [PATCH v3] aic94xx: Increase can_queue for better performance |
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Hi all,
Below is a patch that sets can_queue in the aic94xx driver's scsi_host to better performing values than what's there currently. It seems that asd_ha->seq.can_queue reflects the number of requests that can be queued per controller; so long as there's one scsi_host per controller, it seems logical that the scsi_host ought to have the same can_queue value. To the best of my (still limited) knowledge, this method provides the correct value.
The effect of leaving this value set to 1 is terrible performance in the case of either (a) certain Maxtor SAS drives flying solo or (b) flooding several disks with I/O simultaneously (md-raid). There may be more scenarios where we see similar problems that I haven't uncovered.
--D
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
diff --git a/drivers/scsi/aic94xx/aic94xx_init.c b/drivers/scsi/aic94xx/aic94xx_init.c index 3e25e31..5c6d457 100644 --- a/drivers/scsi/aic94xx/aic94xx_init.c +++ b/drivers/scsi/aic94xx/aic94xx_init.c @@ -623,6 +623,8 @@ static int __devinit asd_pci_probe(struc asd_ha->hw_prof.bios.present ? "build " : "not present", asd_ha->hw_prof.bios.bld);
+ shost->can_queue = asd_ha->seq.can_queue; + if (use_msi) pci_enable_msi(asd_ha->pcidev);
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