From 2ebe0a93a161e9d0fbbf06da60821ea529e549e9 Mon Sep 17 00:00:00 2001
From: mav <mav@FreeBSD.org>
Date: Thu, 2 Jun 2011 20:56:42 +0000
Subject: When possible, join ranges of subsequest BIO_DELETE requests to
 handle more (up to 2048 instead of 256 or even 64) of them with single TRIM
 request.

OCZ Vertex2/Vertex3 SSDs can handle no more then 64 ranges per TRIM request.
Due to lack of BIO_DELETE clustering now, it means that we could delete no
more then 2MB per request (on FS with 32K block) with limited request rate.
This change increases delete rate on Vertex2 from 250MB/s to 950MB/s.
---
 sys/cam/ata/ata_da.c | 34 +++++++++++++++++++++++++---------
 1 file changed, 25 insertions(+), 9 deletions(-)

(limited to 'sys')

diff --git a/sys/cam/ata/ata_da.c b/sys/cam/ata/ata_da.c
index 7418e1e..f918956 100644
--- a/sys/cam/ata/ata_da.c
+++ b/sys/cam/ata/ata_da.c
@@ -115,10 +115,11 @@ struct disk_params {
 };
 
 #define TRIM_MAX_BLOCKS	4
-#define TRIM_MAX_RANGES	TRIM_MAX_BLOCKS * 64
+#define TRIM_MAX_RANGES	(TRIM_MAX_BLOCKS * 64)
+#define TRIM_MAX_BIOS	(TRIM_MAX_RANGES * 8)
 struct trim_request {
 	uint8_t		data[TRIM_MAX_RANGES * 8];
-	struct bio	*bps[TRIM_MAX_RANGES];
+	struct bio	*bps[TRIM_MAX_BIOS];
 };
 
 struct ada_softc {
@@ -1067,7 +1068,8 @@ adastart(struct cam_periph *periph, union ccb *start_ccb)
 		    (bp = bioq_first(&softc->trim_queue)) != 0) {
 			struct trim_request *req = &softc->trim_req;
 			struct bio *bp1;
-			int bps = 0, ranges = 0;
+			uint64_t lastlba = (uint64_t)-1;
+			int bps = 0, c, lastcount = 0, off, ranges = 0;
 
 			softc->trim_running = 1;
 			bzero(req, sizeof(*req));
@@ -1078,10 +1080,22 @@ adastart(struct cam_periph *periph, union ccb *start_ccb)
 				    softc->params.secsize;
 
 				bioq_remove(&softc->trim_queue, bp1);
-				while (count > 0) {
-					int c = min(count, 0xffff);
-					int off = ranges * 8;
 
+				/* Try to extend the previous range. */
+				if (lba == lastlba) {
+					c = min(count, 0xffff - lastcount);
+					lastcount += c;
+					off = (ranges - 1) * 8;
+					req->data[off + 6] = lastcount & 0xff;
+					req->data[off + 7] =
+					    (lastcount >> 8) & 0xff;
+					count -= c;
+					lba += c;
+				}
+
+				while (count > 0) {
+					c = min(count, 0xffff);
+					off = ranges * 8;
 					req->data[off + 0] = lba & 0xff;
 					req->data[off + 1] = (lba >> 8) & 0xff;
 					req->data[off + 2] = (lba >> 16) & 0xff;
@@ -1092,11 +1106,14 @@ adastart(struct cam_periph *periph, union ccb *start_ccb)
 					req->data[off + 7] = (c >> 8) & 0xff;
 					lba += c;
 					count -= c;
+					lastcount = c;
 					ranges++;
 				}
+				lastlba = lba;
 				req->bps[bps++] = bp1;
 				bp1 = bioq_first(&softc->trim_queue);
-				if (bp1 == NULL ||
+				if (bps >= TRIM_MAX_BIOS ||
+				    bp1 == NULL ||
 				    bp1->bio_bcount / softc->params.secsize >
 				    (softc->trim_max_ranges - ranges) * 0xffff)
 					break;
@@ -1370,8 +1387,7 @@ adadone(struct cam_periph *periph, union ccb *done_ccb)
 			    (struct trim_request *)ataio->data_ptr;
 			int i;
 
-			for (i = 1; i < softc->trim_max_ranges &&
-			    req->bps[i]; i++) {
+			for (i = 1; i < TRIM_MAX_BIOS && req->bps[i]; i++) {
 				struct bio *bp1 = req->bps[i];
 				
 				bp1->bio_resid = bp->bio_resid;
-- 
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