[PATCH 1/4] common/scsi_debug: don't slow down I/O

scsi_debug by defaults delays I/O and doesn't support multi-page I/O.
Flipping these defaults speed up each test using scsi_debug by more than
an order of magnitute on my test systems.

Signed-off-by: Christoph Hellwig <[email protected]>
---
 common/scsi_debug | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/common/scsi_debug b/common/scsi_debug
index c3fe7be623fa..91665547bc0c 100644
--- a/common/scsi_debug
+++ b/common/scsi_debug
@@ -59,7 +59,9 @@ _get_scsi_debug_dev()
 		let physical=physical/2
 		let phys_exp=phys_exp+1
 	done
-	opts="sector_size=$logical physblk_exp=$phys_exp lowest_aligned=$unaligned dev_size_mb=$size $@"
+	opts="sector_size=$logical physblk_exp=$phys_exp"
+	opts="${opts} lowest_aligned=$unaligned dev_size_mb=$size"
+	opts="${opts} delay=0 clustering=1 $@"
 	echo "scsi_debug options $opts" >> $seqres.full
 	modprobe scsi_debug $opts
 	[ $? -eq 0 ] || _fail "scsi_debug modprobe failed"
-- 
2.53.0