From db39363c029cd9e74661ef059a17785d1c62a851 Mon Sep 17 00:00:00 2001 From: Mark Haverkamp Date: Wed, 11 Jan 2006 09:28:29 -0800 Subject: [SCSI] aacraid: 17 element sg performance update 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 Signed-off-by: James Bottomley --- drivers/scsi/aacraid/aacraid.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'drivers/scsi/aacraid/aacraid.h') diff --git a/drivers/scsi/aacraid/aacraid.h b/drivers/scsi/aacraid/aacraid.h index 30fd8d6e3f3..66dbb6d2c50 100644 --- a/drivers/scsi/aacraid/aacraid.h +++ b/drivers/scsi/aacraid/aacraid.h @@ -531,6 +531,13 @@ struct aac_driver_ident */ #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 -- cgit v1.2.3