Author: rgoers
Date: Fri Apr 19 06:09:53 2013
New Revision: 1469709
URL: http://svn.apache.org/r1469709
Log:
LOG4J2-214 - Async documentation update
Added:
logging/log4j/log4j2/trunk/src/site/resources/images/async-latency-histogram-64-threads.png
(with props)
Modified:
logging/log4j/log4j2/trunk/core/src/site/xdoc/index.xml
logging/log4j/log4j2/trunk/src/changes/changes.xml
logging/log4j/log4j2/trunk/src/site/resources/images/async-average-latency.png
logging/log4j/log4j2/trunk/src/site/resources/images/async-max-latency-99.99pct.png
logging/log4j/log4j2/trunk/src/site/xdoc/index.xml
logging/log4j/log4j2/trunk/src/site/xdoc/manual/async.xml
Modified: logging/log4j/log4j2/trunk/core/src/site/xdoc/index.xml
URL:
http://svn.apache.org/viewvc/logging/log4j/log4j2/trunk/core/src/site/xdoc/index.xml?rev=1469709&r1=1469708&r2=1469709&view=diff
==============================================================================
--- logging/log4j/log4j2/trunk/core/src/site/xdoc/index.xml (original)
+++ logging/log4j/log4j2/trunk/core/src/site/xdoc/index.xml Fri Apr 19 06:09:53
2013
@@ -46,6 +46,7 @@
<li>Async Loggers require the LMAX Disruptor.</li>
<li>SMTPAppender requires Javax Mail.</li>
<li>JMSQueueAppender and JMSTopicAppender require a JMS
implementation like geronimo-jms.</li>
+ <li>Windows color support requires Jansi.</li>
</ul>
</section>
Modified: logging/log4j/log4j2/trunk/src/changes/changes.xml
URL:
http://svn.apache.org/viewvc/logging/log4j/log4j2/trunk/src/changes/changes.xml?rev=1469709&r1=1469708&r2=1469709&view=diff
==============================================================================
--- logging/log4j/log4j2/trunk/src/changes/changes.xml (original)
+++ logging/log4j/log4j2/trunk/src/changes/changes.xml Fri Apr 19 06:09:53 2013
@@ -23,6 +23,9 @@
<body>
<release version="2.0-beta5" date="@TBD@" description="Bug fixes and
enhancements">
+ <action issue="LOG4J2-214" dev="rgoers" type="update" due-to="Remko
Popma">
+ Async documentation update.
+ </action>
<action issue="LOG4J2-212" dev="rgoers" type="fix">
Loggers without a "." had no parent logger.
</action>
Modified:
logging/log4j/log4j2/trunk/src/site/resources/images/async-average-latency.png
URL:
http://svn.apache.org/viewvc/logging/log4j/log4j2/trunk/src/site/resources/images/async-average-latency.png?rev=1469709&r1=1469708&r2=1469709&view=diff
==============================================================================
Binary files - no diff available.
Added:
logging/log4j/log4j2/trunk/src/site/resources/images/async-latency-histogram-64-threads.png
URL:
http://svn.apache.org/viewvc/logging/log4j/log4j2/trunk/src/site/resources/images/async-latency-histogram-64-threads.png?rev=1469709&view=auto
==============================================================================
Binary file - no diff available.
Propchange:
logging/log4j/log4j2/trunk/src/site/resources/images/async-latency-histogram-64-threads.png
------------------------------------------------------------------------------
svn:mime-type = application/octet-stream
Modified:
logging/log4j/log4j2/trunk/src/site/resources/images/async-max-latency-99.99pct.png
URL:
http://svn.apache.org/viewvc/logging/log4j/log4j2/trunk/src/site/resources/images/async-max-latency-99.99pct.png?rev=1469709&r1=1469708&r2=1469709&view=diff
==============================================================================
Binary files - no diff available.
Modified: logging/log4j/log4j2/trunk/src/site/xdoc/index.xml
URL:
http://svn.apache.org/viewvc/logging/log4j/log4j2/trunk/src/site/xdoc/index.xml?rev=1469709&r1=1469708&r2=1469709&view=diff
==============================================================================
--- logging/log4j/log4j2/trunk/src/site/xdoc/index.xml (original)
+++ logging/log4j/log4j2/trunk/src/site/xdoc/index.xml Fri Apr 19 06:09:53 2013
@@ -97,7 +97,7 @@
<subsection name="Requirements">
<p>
- Log4j 2 requires Java 5 but takes advantage of enhancements in
Java 6 to improve performance.
+ Log4j 2 requires Java 6.
Some features require optional dependencies; the documentation
for these features specifies the
dependencies.
</p>
Modified: logging/log4j/log4j2/trunk/src/site/xdoc/manual/async.xml
URL:
http://svn.apache.org/viewvc/logging/log4j/log4j2/trunk/src/site/xdoc/manual/async.xml?rev=1469709&r1=1469708&r2=1469709&view=diff
==============================================================================
--- logging/log4j/log4j2/trunk/src/site/xdoc/manual/async.xml (original)
+++ logging/log4j/log4j2/trunk/src/site/xdoc/manual/async.xml Fri Apr 19
06:09:53 2013
@@ -761,25 +761,101 @@
<a name="Latency" />
<h4>Latency</h4>
- <p>The latency comparison below is done by
logging at
+ <p>Latency tests are done by logging at
less than saturation, measuring how long a call
to Logger.log
takes to return. After each call to Logger.log,
the test waits
for 10 microseconds * threadCount before
continuing.
Each thread logs 5 million messages.
</p>
+ <p>All the latency measurements below are
results of tests run
+ on Solaris 10 (64bit) with JDK1.7.0_06, 4-core
Xeon X5570 dual CPU
+ @2.93Ghz with hyperthreading switched on (16
virtual cores).</p>
+ <p><img
src="../images/async-latency-histogram-64-threads.png" /></p>
+ <p>Note that this is log-scale, not linear.
+ The above graph compares the latency
distributions of
+ an asynchronous logger and a Log4j 1.2.17 Async
Appender.
+ This shows the latency of one thread
+ during a test where 64 threads are logging in
parallel.
+ The test was run once for the async logger and
once for the
+ async appender.</p>
+ <table>
+ <tr>
+ <th></th>
+ <th colspan="2" >Average latency</th>
+ <th colspan="2">99% observations
+ less than</th>
+ <th colspan="2">99.99%
+ observations less than</th>
+ </tr>
+ <tr>
+ <th></th>
+ <th>1 thread</th>
+ <th>64 threads</th>
+ <th>1 thread</th>
+ <th>64 threads</th>
+ <th>1 thread</th>
+ <th>64 threads</th>
+ </tr>
+ <tr>
+ <td>Log4j2: Loggers all async</td>
+ <td align="right">677</td>
+ <td align="right">4,135</td>
+ <td align="right">1,638</td>
+ <td align="right">4,096</td>
+ <td align="right">8,192</td>
+ <td align="right">16,128</td>
+ </tr>
+ <tr>
+ <td>Log4j2: Loggers mixed
+ sync/async</td>
+ <td align="right">648</td>
+ <td align="right">4,873</td>
+ <td align="right">1,228</td>
+ <td align="right">4,096</td>
+ <td align="right">8,192</td>
+ <td align="right">16,384</td>
+ </tr>
+ <tr>
+ <td>Log4j2: Async Appender</td>
+ <td align="right">2,423</td>
+ <td align="right">2,117,722</td>
+ <td align="right">4,096</td>
+ <td align="right">67,108,864</td>
+ <td align="right">16,384</td>
+ <td align="right">268,435,456</td>
+ </tr>
+ <tr>
+ <td>Log4j1: Async Appender</td>
+ <td align="right">1,562</td>
+ <td align="right">1,781,404</td>
+ <td align="right">4,096</td>
+ <td align="right">109,051,904</td>
+ <td align="right">16,384</td>
+ <td align="right">268,435,456</td>
+ </tr>
+ <tr>
+ <td>Logback: Async Appender</td>
+ <td align="right">2,123</td>
+ <td align="right">2,079,020</td>
+ <td align="right">3,276</td>
+ <td align="right">67,108,864</td>
+ <td align="right">14,745</td>
+ <td align="right">268,435,456</td>
+ </tr>
+ <caption align="top">Latency of a call to Logger.log()
in nanoseconds</caption>
+ </table>
<p>
- <img src="../images/async-average-latency.png"
/>
- </p>
- <p>
- Note that the scale of the latency comparison
graphs is
- logarithmic, not linear.
- That makes it a bit difficult to see, but the
average latency of
- asynchronous loggers is half to one third of
the latency of
- ArrayBlockingQueue-based asynchronous appenders
in scenarios
- up to 8 threads. With more threads, the average
latency of
+ The latency comparison graph below is also
log-scale,
+ and shows the average latency of asynchronous
loggers and
+ ArrayBlockingQueue-based asynchronous appenders
+ in scenarios with more and more threads running
in parallel.
+ Up to 8 threads asynchronous appenders have
comparable
+ average latency, two or three times that of
asynchronous loggers.
+ With more threads, the average latency of
asynchronous appenders is orders of magnitude
larger than
asynchronous loggers.
</p>
+ <p><img
src="../images/async-average-latency.png" /></p>
<p>
Applications interested in low latency often
care not only about
average latency, but also about worst-case
latency.
@@ -787,9 +863,9 @@
better when comparing the maximum latency of
99.99% of
observations with other logging methods.
When increasing the number of threads
- the worst case latency of asynchronous loggers
remains more or
- less the same (around 10-20 microseconds)
- where Asynchronous Appenders start experiencing
worst-case
+ the vast majority of latency measurements for
asynchronous
+ loggers stay in the 10-20 microseconds range
+ where Asynchronous Appenders start experiencing
many
latency spikes in the 100 millisecond range, a
difference of
four orders of magnitude.
</p>
