<h3>Entries from August 2016.</h3>
+ <div class="entry">
+ <div class="title">
+ <a href="http://people.skolelinux.org/pere/blog/Coz_can_help_you_find_bottlenecks_in_multi_threaded_software___nice_free_software.html">Coz can help you find bottlenecks in multi-threaded software - nice free software</a>
+ </div>
+ <div class="date">
+ 11th August 2016
+ </div>
+ <div class="body">
+ <p>This summer, I read a great article
+"<a href="https://www.usenix.org/publications/login/summer2016/curtsinger">coz:
+This Is the Profiler You're Looking For</a>" in USENIX ;login: about
+how to profile multi-threaded programs. It presented a system for
+profiling software by running experiences in the running program,
+testing how run time performance is affected by "speeding up" parts of
+the code to various degrees compared to a normal run. It does this by
+slowing down parallel threads while the "faster up" code is running
+and measure how this affect processing time. The processing time is
+measured using probes inserted into the code, either using progress
+counters (COZ_PROGRESS) or as latency meters (COZ_BEGIN/COZ_END). It
+can also measure unmodified code by measuring complete the program
+runtime and running the program several times instead.</p>
+
+<p>The project and presentation was so inspiring that I would like to
+get the system into Debian. I
+<a href="https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=830708">created
+a WNPP request for it</a> and contacted upstream to try to make the
+system ready for Debian by sending patches. The build process need to
+be changed a bit to avoid running 'git clone' to get dependencies, and
+to include the JavaScript web page used to visualize the collected
+profiling information included in the source package.
+But I expect that should work out fairly soon.</p>
+
+<p>The way the system work is fairly simple. To run an coz experiment
+on a binary with debug symbols available, start the program like this:
+
+<p><blockquote><pre>
+coz run --- program-to-run
+</pre></blockquote></p>
+
+<p>This will create a text file profile.coz with the instrumentation
+information. To show what part of the code affect the performance
+most, use a web browser and either point it to
+<a href="http://plasma-umass.github.io/coz/">http://plasma-umass.github.io/coz/</a>
+or use the copy from git (in the gh-pages branch). Check out this web
+site to have a look at several example profiling runs and get an idea what the end result from the profile runs look like. To make the
+profiling more useful you include <coz.h> and insert the
+COZ_PROGRESS or COZ_BEGIN and COZ_END at appropriate places in the
+code, rebuild and run the profiler. This allow coz to do more
+targeted experiments.</p>
+
+<p>A video published by ACM
+<a href="https://www.youtube.com/watch?v=jE0V-p1odPg">presenting the
+Coz profiler</a> is available from Youtube. There is also a paper
+from the 25th Symposium on Operating Systems Principles available
+titled
+<a href="https://www.usenix.org/conference/atc16/technical-sessions/presentation/curtsinger">Coz:
+finding code that counts with causal profiling</a>.</p>
+
+<p><a href="https://github.com/plasma-umass/coz">The source code</a>
+for Coz is available from github. It will only build with clang
+because it uses a
+<a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55606">C++
+feature missing in GCC</a>, but I've submitted
+<a href="https://github.com/plasma-umass/coz/pull/67">a patch to solve
+it</a> and hope it will be included in the upstream source soon.</p>
+
+<p>Please get in touch if you, like me, would like to see this piece
+of software in Debian. I would very much like some help with the
+packaging effort, as I lack the in depth knowledge on how to package
+C++ libraries.</p>
+
+ </div>
+ <div class="tags">
+
+
+ Tags: <a href="http://people.skolelinux.org/pere/blog/tags/debian">debian</a>, <a href="http://people.skolelinux.org/pere/blog/tags/english">english</a>, <a href="http://people.skolelinux.org/pere/blog/tags/nice free software">nice free software</a>.
+
+
+ </div>
+ </div>
+ <div class="padding"></div>
+
<div class="entry">
<div class="title">
<a href="http://people.skolelinux.org/pere/blog/Sales_number_for_the_Free_Culture_translation__first_half_of_2016.html">Sales number for the Free Culture translation, first half of 2016</a>
<li><a href="http://people.skolelinux.org/pere/blog/archive/2016/07/">July (2)</a></li>
-<li><a href="http://people.skolelinux.org/pere/blog/archive/2016/08/">August (3)</a></li>
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2016/08/">August (4)</a></li>
</ul></li>
<li><a href="http://people.skolelinux.org/pere/blog/tags/chrpath">chrpath (2)</a></li>
- <li><a href="http://people.skolelinux.org/pere/blog/tags/debian">debian (133)</a></li>
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/debian">debian (134)</a></li>
<li><a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu (157)</a></li>
<li><a href="http://people.skolelinux.org/pere/blog/tags/drivstoffpriser">drivstoffpriser (4)</a></li>
- <li><a href="http://people.skolelinux.org/pere/blog/tags/english">english (325)</a></li>
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/english">english (326)</a></li>
<li><a href="http://people.skolelinux.org/pere/blog/tags/fiksgatami">fiksgatami (23)</a></li>
<li><a href="http://people.skolelinux.org/pere/blog/tags/multimedia">multimedia (39)</a></li>
- <li><a href="http://people.skolelinux.org/pere/blog/tags/nice free software">nice free software (7)</a></li>
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/nice free software">nice free software (8)</a></li>
<li><a href="http://people.skolelinux.org/pere/blog/tags/norsk">norsk (276)</a></li>
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