[PATCH 1/1] aacraid: improve queue balancing

["Salyzyn, Mark" <Mark_Salyzyn@xxxxxxxxxxx>]

The adapter queue is divided up equally to all the arrays to prevent command starvation to any individual array. On the other hand, physical targets are only granted a queue depth of one each. The code prior to this patch used to deal with the incremental discovery of targets, but the driver knows how many arrays are present prior to the scan so this knowledge is used to generate a better estimate for the queue depth.

Remove the capability of 'physical=0' from preventing access to the class of adapters that have the RAID/SCSI mode of operation since none of the physicals on the SCSI channel are candidates ever for an array.

As always, the user can override this default queue depth policy by making the appropriate adjustments utilizing sysfs.

This attached patch is against current scsi-misc-2.6.

ObligatoryDisclaimer: Please accept my condolences regarding Outlook's handling of patch attachments (inline gets damaged, use attachment).

Signed-off-by: Mark Salyzyn <aacraid@xxxxxxxxxxx>

 drivers/scsi/aacraid/linit.c |   23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

--- a/drivers/scsi/aacraid/linit.c      2008-01-08 16:38:32.783320829 -0500
+++ b/drivers/scsi/aacraid/linit.c      2008-01-08 16:55:07.805050564 -0500
@@ -401,16 +401,14 @@

 static int aac_slave_configure(struct scsi_device *sdev)
 {
+       struct aac_dev *aac = (struct aac_dev *)sdev->host->hostdata;
        if ((sdev->type == TYPE_DISK) &&
-                       (sdev_channel(sdev) != CONTAINER_CHANNEL)) {
+                       (sdev_channel(sdev) != CONTAINER_CHANNEL) &&
+                       (!aac->raid_scsi_mode || (sdev_channel(sdev) != 2))) {
                if (expose_physicals == 0)
                        return -ENXIO;
-               if (expose_physicals < 0) {
-                       struct aac_dev *aac =
-                               (struct aac_dev *)sdev->host->hostdata;
-                       if (!aac->raid_scsi_mode || (sdev_channel(sdev) != 2))
-                               sdev->no_uld_attach = 1;
-               }
+               if (expose_physicals < 0)
+                       sdev->no_uld_attach = 1;
        }
        if (sdev->tagged_supported && (sdev->type == TYPE_DISK) &&
                        (sdev_channel(sdev) == CONTAINER_CHANNEL)) {
@@ -419,6 +417,7 @@
                unsigned num_lsu = 0;
                unsigned num_one = 0;
                unsigned depth;
+               unsigned cid;

                /*
                 * Firmware has an individual device recovery time typically
@@ -426,11 +425,15 @@
                 */
                if (sdev->timeout < (45 * HZ))
                        sdev->timeout = 45 * HZ;
+               for (cid = 0; cid < aac->maximum_num_containers; ++cid)
+                       if (aac->fsa_dev[cid].valid)
+                               ++num_lsu;
                __shost_for_each_device(dev, host) {
                        if (dev->tagged_supported && (dev->type == TYPE_DISK) &&

-                               (sdev_channel(dev) == CONTAINER_CHANNEL))
-                               ++num_lsu;
-                       else
+                               (sdev_channel(dev) == CONTAINER_CHANNEL)) {
+                               if (!aac->fsa_dev[sdev_id(dev)].valid)
+                                       ++num_lsu;
+                       } else
                                ++num_one;
                }
                if (num_lsu == 0)

Sincerely -- Mark Salyzyn

Attachment: aacraid_queue_depth.patch
Description: aacraid_queue_depth.patch