From e24fb7a166deab8ef6033b1947bd5b8e0bdfebe5 Mon Sep 17 00:00:00 2001
From: Bart Van Assche <bvanassche@acm.org>
Date: Thu, 31 Jan 2013 14:05:25 +0000
Subject: [PATCH] ib_srpt README: Document cmd_sg_entries

git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@4750 d57e44dd-8a1f-0410-8b47-8ef2f437770f
---
 srpt/README | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/srpt/README b/srpt/README
index 7b43baf7c..1d86add1b 100644
--- a/srpt/README
+++ b/srpt/README
@@ -343,6 +343,13 @@ Performance Notes - Target Side
 Performance Notes - Initiator Side
 ----------------------------------
 
+* Choose a proper value for the ib_srp kernel module parameter
+  cmd_sg_entries. The default value 12 works well for buffered reads while
+  the throughput for write-dominated workloads improves by changing this value
+  into 255. One way to set this kernel module parameter is as follows:
+
+  echo options ib_srp cmd_sg_entries=255 >>/etc/modprobe.d/ib_srp.conf
+
 * For multithreaded workloads using small block sizes changing rq_affinity
   into 2 improves IOPS significantly (Linux kernel 3.1 and later; see also
   commit 5757a6d76cdf6dda2a492c09b985c015e86779b1).