Add notes for 2020-02-07

content/posts/2020-02.md

@@ -303,4 +303,40 @@ $ ./run.sh -s http://localhost:8983/solr/statistics -a import -o ~/Downloads/sta
 
 - OK that imported! I wonder if it works... maybe I'll try another day
 
+## 2020-02-07
+
+- I did some investigation into DSpace indexing performance using flame graphs
+  - Excellent introduction: http://www.brendangregg.com/flamegraphs.html
+  - Using flame graphs with java: https://netflixtechblog.com/java-in-flames-e763b3d32166
+  - Fantastic wrapper scripts for doing perf on Java processes: https://github.com/jvm-profiling-tools/perf-map-agent
+
+```
+$ cd ~/src/git/perf-map-agent
+$ cmake     .
+$ make
+$ ./bin/create-links-in ~/.local/bin
+$ export FLAMEGRAPH_DIR=/home/aorth/src/git/FlameGraph
+$ export JAVA_HOME=/usr/lib/jvm/java-8-openjdk
+$ export JAVA_OPTS="-XX:+PreserveFramePointer"
+$ ~/dspace63/bin/dspace index-discovery -b &
+# pid of tomcat java process
+$ perf-java-flames 4478
+# pid of java indexing process
+$ perf-java-flames 11359
+```
+
+- All Java processes need to have `-XX:+PreserveFramePointer` if you want to trace their methods
+- I did the same tests against DSpace 5.8 and 6.4-SNAPSHOT's CLI indexing process and Tomcat process
+  - For what it's worth, it appears all the Hibernate stuff is in the CLI processes, so we don't need to trace the Tomcat process
+- Here is the flame graph for DSpace 5.8's `dspace index-discovery -b` java process:
+
+![DSpace 5.8 index-discovery flame graph](/cgspace-notes/2020/02/flamegraph-java-cli-dspace58.svg)
+
+- Here is the flame graph for DSpace 6.4-SNAPSHOT's `dspace index-discovery -b` java process:
+
+![DSpace 6.4-SNAPSHOT index-discovery flame graph](/cgspace-notes/2020/02/flamegraph-java-cli-dspace64-snapshot.svg)
+
+- If the width of the stacks indicates time, then it's clear that Hibernate takes longer...
+- Apparently there is a "flame diff" tool, I wonder if we can use that to compare!
+
 <!-- vim: set sw=2 ts=2: -->

docs/2020-02/index.html

@@ -20,7 +20,7 @@ The code finally builds and runs with a fresh install
 <meta property="og:type" content="article" />
 <meta property="og:url" content="https://alanorth.github.io/cgspace-notes/2020-02/" />
 <meta property="article:published_time" content="2020-02-02T11:56:30+02:00" />
-<meta property="article:modified_time" content="2020-02-06T12:47:25+02:00" />
+<meta property="article:modified_time" content="2020-02-06T16:54:41+02:00" />
 
 <meta name="twitter:card" content="summary"/>
 <meta name="twitter:title" content="February, 2020"/>
@@ -45,9 +45,9 @@ The code finally builds and runs with a fresh install
   "@type": "BlogPosting",
   "headline": "February, 2020",
   "url": "https:\/\/alanorth.github.io\/cgspace-notes\/2020-02\/",
-  "wordCount": "2069",
+  "wordCount": "2254",
   "datePublished": "2020-02-02T11:56:30+02:00",
-  "dateModified": "2020-02-06T12:47:25+02:00",
+  "dateModified": "2020-02-06T16:54:41+02:00",
   "author": {
     "@type": "Person",
     "name": "Alan Orth"
@@ -420,6 +420,46 @@ $ ./run.sh -s http://localhost:8080/solr/statistics-2019 -a import -o ~/Download
 </code></pre><ul>
 <li>OK that imported! I wonder if it works&hellip; maybe I&rsquo;ll try another day</li>
 </ul>
+<h2 id="2020-02-07">2020-02-07</h2>
+<ul>
+<li>I did some investigation into DSpace indexing performance using flame graphs
+<ul>
+<li>Excellent introduction: <a href="http://www.brendangregg.com/flamegraphs.html">http://www.brendangregg.com/flamegraphs.html</a></li>
+<li>Using flame graphs with java: <a href="https://netflixtechblog.com/java-in-flames-e763b3d32166">https://netflixtechblog.com/java-in-flames-e763b3d32166</a></li>
+<li>Fantastic wrapper scripts for doing perf on Java processes: <a href="https://github.com/jvm-profiling-tools/perf-map-agent">https://github.com/jvm-profiling-tools/perf-map-agent</a></li>
+</ul>
+</li>
+</ul>
+<pre><code>$ cd ~/src/git/perf-map-agent
+$ cmake     .
+$ make
+$ ./bin/create-links-in ~/.local/bin
+$ export FLAMEGRAPH_DIR=/home/aorth/src/git/FlameGraph
+$ export JAVA_HOME=/usr/lib/jvm/java-8-openjdk
+$ export JAVA_OPTS=&quot;-XX:+PreserveFramePointer&quot;
+$ ~/dspace63/bin/dspace index-discovery -b &amp;
+# pid of tomcat java process
+$ perf-java-flames 4478
+# pid of java indexing process
+$ perf-java-flames 11359
+</code></pre><ul>
+<li>All Java processes need to have <code>-XX:+PreserveFramePointer</code> if you want to trace their methods</li>
+<li>I did the same tests against DSpace 5.8 and 6.4-SNAPSHOT&rsquo;s CLI indexing process and Tomcat process
+<ul>
+<li>For what it&rsquo;s worth, it appears all the Hibernate stuff is in the CLI processes, so we don&rsquo;t need to trace the Tomcat process</li>
+</ul>
+</li>
+<li>Here is the flame graph for DSpace 5.8&rsquo;s <code>dspace index-discovery -b</code> java process:</li>
+</ul>
+<p><img src="/cgspace-notes/2020/02/flamegraph-java-cli-dspace58.svg" alt="DSpace 5.8 index-discovery flame graph"></p>
+<ul>
+<li>Here is the flame graph for DSpace 6.4-SNAPSHOT&rsquo;s <code>dspace index-discovery -b</code> java process:</li>
+</ul>
+<p><img src="/cgspace-notes/2020/02/flamegraph-java-cli-dspace64-snapshot.svg" alt="DSpace 6.4-SNAPSHOT index-discovery flame graph"></p>
+<ul>
+<li>If the width of the stacks indicates time, then it&rsquo;s clear that Hibernate takes longer&hellip;</li>
+<li>Apparently there is a &ldquo;flame diff&rdquo; tool, I wonder if we can use that to compare!</li>
+</ul>
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docs/sitemap.xml

@@ -4,27 +4,27 @@
   
   <url>
     <loc>https://alanorth.github.io/cgspace-notes/categories/</loc>
-    <lastmod>2020-02-06T12:47:25+02:00</lastmod>
+    <lastmod>2020-02-06T16:54:41+02:00</lastmod>
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   <url>
     <loc>https://alanorth.github.io/cgspace-notes/</loc>
-    <lastmod>2020-02-06T12:47:25+02:00</lastmod>
+    <lastmod>2020-02-06T16:54:41+02:00</lastmod>
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   <url>
     <loc>https://alanorth.github.io/cgspace-notes/2020-02/</loc>
-    <lastmod>2020-02-06T12:47:25+02:00</lastmod>
+    <lastmod>2020-02-06T16:54:41+02:00</lastmod>
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     <loc>https://alanorth.github.io/cgspace-notes/categories/notes/</loc>
-    <lastmod>2020-02-06T12:47:25+02:00</lastmod>
+    <lastmod>2020-02-06T16:54:41+02:00</lastmod>
   </url>
   
   <url>
     <loc>https://alanorth.github.io/cgspace-notes/posts/</loc>
-    <lastmod>2020-02-06T12:47:25+02:00</lastmod>
+    <lastmod>2020-02-06T16:54:41+02:00</lastmod>
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