svn commit: r323834 - head/sys/dev/nvme

[Warner Losh]

Author: imp
Date: Wed Sep 20 21:42:25 2017
New Revision: 323834
URL: https://svnweb.freebsd.org/changeset/base/323834

Log:
  Fix queue depth for nda.
  
  1/4 of the number of queues times queue entries is too limiting. It
  works up to about 4k IOPS / 3.0GB/s for hardware that can do
  4.4k/3.2GB/s with nvd. 3/4 works better, though it highlights issues
  in the fairness of nda's choice of TRIM vs READ. That will be fixed
  separately.

Modified:
  head/sys/dev/nvme/nvme_ctrlr.c

Modified: head/sys/dev/nvme/nvme_ctrlr.c
==============================================================================
--- head/sys/dev/nvme/nvme_ctrlr.c	Wed Sep 20 21:29:54 2017	(r323833)
+++ head/sys/dev/nvme/nvme_ctrlr.c	Wed Sep 20 21:42:25 2017	(r323834)
@@ -151,7 +151,7 @@ nvme_ctrlr_construct_io_qpairs(struct nvme_controller 
 	 * not a hard limit and will need to be revisitted when the upper layers
 	 * of the storage system grows multi-queue support.
 	 */
-	ctrlr->max_hw_pend_io = num_trackers * ctrlr->num_io_queues / 4;
+	ctrlr->max_hw_pend_io = num_trackers * ctrlr->num_io_queues * 3 / 4;
 
 	/*
 	 * This was calculated previously when setting up interrupts, but