Received From Mark Salyzyn.
The Jaguar and Corsair class of adapters (2410, 2810, 2610, 21610, CERC)
perform better (about 10% better read performance, write performance
neutral) with current Firmware if the OS limits the number of scatter
gather elements to 17 per request.
Signed-off-by: Mark Haverkamp <markh@xxxxxxxx>
--- scsi-misc-aac.orig/drivers/scsi/aacraid/aacraid.h 2006-01-11 09:19:50.000000000 -0800
+++ scsi-misc-aac/drivers/scsi/aacraid/aacraid.h 2006-01-11 09:20:11.000000000 -0800
@@ -532,6 +532,13 @@
#define AAC_QUIRK_MASTER 0x0008
/*
+ * Some adapter firmware perform poorly when it must split up scatter gathers
+ * in order to deal with the limits of the underlying CHIM. This limit in this
+ * class of adapters is 17 scatter gather elements.
+ */
+#define AAC_QUIRK_17SG 0x0010
+
+/*
* The adapter interface specs all queues to be located in the same
* physically contigous block. The host structure that defines the
* commuication queues will assume they are each a separate physically
--- scsi-misc-aac.orig/drivers/scsi/aacraid/linit.c 2006-01-11 09:20:08.000000000 -0800
+++ scsi-misc-aac/drivers/scsi/aacraid/linit.c 2006-01-11 09:20:11.000000000 -0800
@@ -201,10 +201,10 @@
{ aac_rkt_init, "aacraid", "ADAPTEC ", "Callisto ", 2, AAC_QUIRK_MASTER }, /* Jupiter Platform */
{ aac_rx_init, "aacraid", "ADAPTEC ", "ASR-2020SA ", 1 }, /* ASR-2020SA SATA PCI-X ZCR (Skyhawk) */
{ aac_rx_init, "aacraid", "ADAPTEC ", "ASR-2025SA ", 1 }, /* ASR-2025SA SATA SO-DIMM PCI-X ZCR (Terminator) */
- { aac_rx_init, "aacraid", "ADAPTEC ", "AAR-2410SA SATA ", 1 }, /* AAR-2410SA PCI SATA 4ch (Jaguar II) */
- { aac_rx_init, "aacraid", "DELL ", "CERC SR2 ", 1 }, /* CERC SATA RAID 2 PCI SATA 6ch (DellCorsair) */
- { aac_rx_init, "aacraid", "ADAPTEC ", "AAR-2810SA SATA ", 1 }, /* AAR-2810SA PCI SATA 8ch (Corsair-8) */
- { aac_rx_init, "aacraid", "ADAPTEC ", "AAR-21610SA SATA", 1 }, /* AAR-21610SA PCI SATA 16ch (Corsair-16) */
+ { aac_rx_init, "aacraid", "ADAPTEC ", "AAR-2410SA SATA ", 1, AAC_QUIRK_17SG }, /* AAR-2410SA PCI SATA 4ch (Jaguar II) */
+ { aac_rx_init, "aacraid", "DELL ", "CERC SR2 ", 1, AAC_QUIRK_17SG }, /* CERC SATA RAID 2 PCI SATA 6ch (DellCorsair) */
+ { aac_rx_init, "aacraid", "ADAPTEC ", "AAR-2810SA SATA ", 1, AAC_QUIRK_17SG }, /* AAR-2810SA PCI SATA 8ch (Corsair-8) */
+ { aac_rx_init, "aacraid", "ADAPTEC ", "AAR-21610SA SATA", 1, AAC_QUIRK_17SG }, /* AAR-21610SA PCI SATA 16ch (Corsair-16) */
{ aac_rx_init, "aacraid", "ADAPTEC ", "ASR-2026ZCR ", 1 }, /* ESD SO-DIMM PCI-X SATA ZCR (Prowler) */
{ aac_rx_init, "aacraid", "ADAPTEC ", "AAR-2610SA ", 1 }, /* SATA 6Ch (Bearcat) */
{ aac_rx_init, "aacraid", "ADAPTEC ", "ASR-2240S ", 1 }, /* ASR-2240S (SabreExpress) */
@@ -854,6 +854,13 @@
= (aac->scsi_host_ptr->sg_tablesize * 8) + 112;
}
+ if ((aac_drivers[index].quirks & AAC_QUIRK_17SG) &&
+ (aac->scsi_host_ptr->sg_tablesize > 17)) {
+ aac->scsi_host_ptr->sg_tablesize = 17;
+ aac->scsi_host_ptr->max_sectors
+ = (aac->scsi_host_ptr->sg_tablesize * 8) + 112;
+ }
+
/*
* Firware printf works only with older firmware.
*/
--
Mark Haverkamp <markh@xxxxxxxx>
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