From 37a08634993cffdab4d410ab13e5f11c7e6b73ab Mon Sep 17 00:00:00 2001
From: Ben Hutchings <ben@decadent.org.uk>
Date: Thu, 28 Aug 2014 12:06:55 -0700
Subject: [PATCH] Add blk-mq slide

---
 index.html | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/index.html b/index.html
index 68e0fe8..b58ae67 100644
--- a/index.html
+++ b/index.html
@@ -379,6 +379,32 @@
   </ul>
 </div>
 
+<div class="slide">
+  <h1>Multiqueue block devices [3.16]</h1>
+  <ul class="incremental">
+    <li>
+      Each block device has a command queue (possibly shared with
+      other devices)
+    </li>
+    <li>
+      Queue may be partly implemented by hardware (NCQ) or only
+      in software
+    </li>
+    <li>
+      A single queue means initiation is serialised and completion
+      involves IPI - can be bottleneck for fast devices
+    </li>
+    <li>
+      High-end SSDs support multiple queues, but kernel needed changes
+      to use them
+    </li>
+    <li>
+      <tt>mtip32xx</tt> driver now supports multiqueue, but SCSI
+      drivers don't yet - may be backport-able?
+    </li>
+  </ul>
+</div>
+
 <div class="slide">
   <h1>Questions?</h1>
 </div>
-- 
2.39.5