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authorMark Haverkamp <markh@osdl.org>2005-08-03 18:38:51 -0400
committerJames Bottomley <jejb@mulgrave.(none)>2005-08-05 17:49:46 -0400
commitbed30de47b034b5f28fb7db2fae4860b9d9c0622 (patch)
tree1dd29e4f8ae3122d8cc642523a6f0cd2ca70bfd3 /drivers/scsi
parentfc789a93994858b5e5a46afb96d0dcf6cc1b6f08 (diff)
[SCSI] aacraid: interupt mitigation
Received from Mark Salyzyn from Adaptec: If more than two commands are outstanding to the controller, there is no need to notify the adapter via a PCI bus transaction of additional commands added into the queue; it will get to them when it works through the produce/consumer indexes. This reduced the PCI traffic in the driver to submit a command to the queue to near zero allowing a significant number of commands to be turned around with no need to block for the PCI bridge to flush the notify request to the adapter. Interrupt mitigation has always been present in the driver; it was turned off because of a bug that prevented one from realizing the usefulness of the feature. This bug is fixed in this patch. Signed-off-by: Mark Haverkamp <markh@osdl.org> Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Diffstat (limited to 'drivers/scsi')
-rw-r--r--drivers/scsi/aacraid/comminit.c4
-rw-r--r--drivers/scsi/aacraid/commsup.c20
2 files changed, 20 insertions, 4 deletions
diff --git a/drivers/scsi/aacraid/comminit.c b/drivers/scsi/aacraid/comminit.c
index 43557bf661f6..75abd0453289 100644
--- a/drivers/scsi/aacraid/comminit.c
+++ b/drivers/scsi/aacraid/comminit.c
@@ -44,7 +44,9 @@
44 44
45#include "aacraid.h" 45#include "aacraid.h"
46 46
47struct aac_common aac_config; 47struct aac_common aac_config = {
48 .irq_mod = 1
49};
48 50
49static int aac_alloc_comm(struct aac_dev *dev, void **commaddr, unsigned long commsize, unsigned long commalign) 51static int aac_alloc_comm(struct aac_dev *dev, void **commaddr, unsigned long commsize, unsigned long commalign)
50{ 52{
diff --git a/drivers/scsi/aacraid/commsup.c b/drivers/scsi/aacraid/commsup.c
index 5322865942e2..a1d303f03480 100644
--- a/drivers/scsi/aacraid/commsup.c
+++ b/drivers/scsi/aacraid/commsup.c
@@ -254,6 +254,7 @@ static void fib_dealloc(struct fib * fibptr)
254static int aac_get_entry (struct aac_dev * dev, u32 qid, struct aac_entry **entry, u32 * index, unsigned long *nonotify) 254static int aac_get_entry (struct aac_dev * dev, u32 qid, struct aac_entry **entry, u32 * index, unsigned long *nonotify)
255{ 255{
256 struct aac_queue * q; 256 struct aac_queue * q;
257 unsigned long idx;
257 258
258 /* 259 /*
259 * All of the queues wrap when they reach the end, so we check 260 * All of the queues wrap when they reach the end, so we check
@@ -263,10 +264,23 @@ static int aac_get_entry (struct aac_dev * dev, u32 qid, struct aac_entry **entr
263 */ 264 */
264 265
265 q = &dev->queues->queue[qid]; 266 q = &dev->queues->queue[qid];
266 267
267 *index = le32_to_cpu(*(q->headers.producer)); 268 idx = *index = le32_to_cpu(*(q->headers.producer));
268 if ((*index - 2) == le32_to_cpu(*(q->headers.consumer))) 269 /* Interrupt Moderation, only interrupt for first two entries */
270 if (idx != le32_to_cpu(*(q->headers.consumer))) {
271 if (--idx == 0) {
272 if (qid == AdapHighCmdQueue)
273 idx = ADAP_HIGH_CMD_ENTRIES;
274 else if (qid == AdapNormCmdQueue)
275 idx = ADAP_NORM_CMD_ENTRIES;
276 else if (qid == AdapHighRespQueue)
277 idx = ADAP_HIGH_RESP_ENTRIES;
278 else if (qid == AdapNormRespQueue)
279 idx = ADAP_NORM_RESP_ENTRIES;
280 }
281 if (idx != le32_to_cpu(*(q->headers.consumer)))
269 *nonotify = 1; 282 *nonotify = 1;
283 }
270 284
271 if (qid == AdapHighCmdQueue) { 285 if (qid == AdapHighCmdQueue) {
272 if (*index >= ADAP_HIGH_CMD_ENTRIES) 286 if (*index >= ADAP_HIGH_CMD_ENTRIES)