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Posted to log4j-dev@logging.apache.org by "Remko Popma (JIRA)" <ji...@apache.org> on 2016/05/02 16:50:12 UTC
[jira] [Updated] (LOG4J2-1179) Log4j performance documentation
[ https://issues.apache.org/jira/browse/LOG4J2-1179?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Remko Popma updated LOG4J2-1179:
--------------------------------
Description:
Reorganize and extend performance data on the site.
*Async Loggers Manual Page*
Should be more focussed. Proposed changes:
* Move _"Location, location, location..."_ section on Location Info to general Performance page (keep anchors and link to the relevant Performance page section to avoid breaking existing links)
* Similarly, move _"Throughput of Logging With Location (includeLocation="true")"_ table with throughput results to general Performance page
* Move _"FileAppender vs. RandomAccessFileAppender"_ section to general Performance page. (Again, keep anchors and link to new section on Performance page to avoid breaking links.)
* Rewrite opening paragraph of Async Logger manual page to remove reference to RandomAccessFile appender
* Rewrite section on _Latency_
** The histogram shows service time (more useful for users is response time: service time + wait time).
** Bar chart diagram on "average latency" is nonsense. Latency is not a normal distribution so terms like "average latency" don't make sense. Remove this. (A histogram showing the full range of percentiles _does_ make sense.)
** Bar chart diagram with max of 99.99% of observations is better than average but still has large drawbacks: this is service time (omitting the crucial wait time) and how high are the peaks in the 0.01% we did not report? Better to remove this and instead show a histogram with the full range of percentages.
*Performance Page*
# Briefly explain about various aspects of "performance": peak measured throughput (what kind of bursts can we deal with?), sustained throughput, and response time (service time + wait time).
# Then show how Log4j 2 compares to the alternatives (Logback, Log4j-1.2 and JUL) on all these three performance dimensions.
# Finally, document some performance trade-offs for Log4j 2 functionality.
*2. Comparison to alternative logging libraries*
Link to Async Loggers page for bursty logging.
Clarify that Async Appender exists to minimize dependencies but should be avoided if performance is a concern. Async Appender is NOT the default and should NOT be used for benchmarking. (I found [this loggly article|https://www.loggly.com/blog/benchmarking-java-logging-frameworks/] very frustrating in that respect.) Should probably also clarify that any benchmark that tests with only one thread doing logging is of limited use.
For various appenders, compare Log4j2 to alternatives with regards to max sustained throughput (and separately, response time).
* [File Appender max sustained thoughput|https://issues.apache.org/jira/browse/LOG4J2-1297?focusedCommentId=15256490&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15256490]
* Socket appender (TCP/UDP)
* Syslog appender (TCP/UDP)
*3. Log4j 2 functionality performance trade-offs*
* including location
* Cost of various layouts (HTML, XML, CSV, Pattern)
* Cost of various Pattern Layout options
* Cost of various appenders (File, RandomAccess File, MemoryMapped File, Console, Rewrite, other?) TODO: decide on layout for these tests.
* Cost of various APIs/wrappers (SLF4J, Log4j1, JUL, Commons Logging)
* JDBC appenders? - different JDBC drivers and target databases may have very different performance. May become a big project. We could do a quick comparison of the JDBC appender to the JDK Derby DB compared against FileAppender just to get an idea of max sustained throughput?
-------------------
Of the existing Performance page sections:
* Briefly mention that disabled logging has no measurable cost, but de-emphasize this section by moving it down the page.
* Parameterized messages: use these JMH [benchmark results|https://issues.apache.org/jira/browse/LOG4J2-1278?focusedCommentId=15216236&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15216236]? (Looks like parameterized messages are currently quite expensive...)
* I like the part about the filters because it a) compares Log4j 2 to Logback and b) considers multithreaded applications. I'll turn this into a JMH test and show the result as a bar chart.
was:
_(Work in progress. Still thinking this through.)_
The web site currently has two performance pages:
*[Performance|https://logging.apache.org/log4j/2.x/performance.html]*
A general performance page comparing Log4j 2 to Logback and Log4j 1. This page is not part of the manual, and the only link to it is from the About top page. This page covers:
* logging turned off (with is<Level>Enabled)
* Parameters vs. String concatenation
* Synchronous logging (to unspecified appender with unspecified layout) - stale (log4j-2.4 improvements are not included)
* Filters (ThreadContextMapFilter and MarkerFilter)
* Environment: MacBook Pro laptop specifying clock speed but omitting OS, JDK and # cores.
*[Async Loggers Performance|https://logging.apache.org/log4j/2.x/manual/async.html#Performance]*
Intended as in-depth analysis of async loggers. Mostly a comparison of Log4j 2 to Logback and Log4j 1. This page covers:
* Synchronous vs. asynchronous logging (stale: synchronous log4j2 logging especially has improved a lot since 2.0-beta5)
* Async Logger vs. Async Appender
* Cost of logging location information (may be improved with LOG4J2-1029)
* Separate analysis for throughput and latency
* FileAppender vs. RandomAccessFileAppender (should not be on this page)
* Environment: laptop Windows 7 with JDK1.7 on 4 cores and enterprise server Solaris 10 with JDK1.7 on 16 cores
*TODO: dedicated Performance section on web site*
I would like to add a Performance section to the site (accessible from the nav side menu). Not sure if this should be part of the manual or under APACHE LOG4J™ 2 in the nav side menu.
This section would include and reorganize what we already have, and in addition have sections (separate pages?) on:
* General tips to improve logging performance
* Cost of various layouts (HTML, XML, CSV, Pattern)
* Cost of various Pattern Layout options
* Cost of various appenders (File, RandomAccess File, MemoryMapped File, Console, Rewrite, other?) TODO: decide on layout for these tests.
* Cost of various APIs/wrappers (SLF4J, Log4j1, JUL, Commons Logging)
> Log4j performance documentation
> -------------------------------
>
> Key: LOG4J2-1179
> URL: https://issues.apache.org/jira/browse/LOG4J2-1179
> Project: Log4j 2
> Issue Type: Documentation
> Components: Documentation, Performance Benchmarks
> Affects Versions: 2.4.1
> Reporter: Remko Popma
> Assignee: Remko Popma
> Fix For: 2.6
>
>
> Reorganize and extend performance data on the site.
> *Async Loggers Manual Page*
> Should be more focussed. Proposed changes:
> * Move _"Location, location, location..."_ section on Location Info to general Performance page (keep anchors and link to the relevant Performance page section to avoid breaking existing links)
> * Similarly, move _"Throughput of Logging With Location (includeLocation="true")"_ table with throughput results to general Performance page
> * Move _"FileAppender vs. RandomAccessFileAppender"_ section to general Performance page. (Again, keep anchors and link to new section on Performance page to avoid breaking links.)
> * Rewrite opening paragraph of Async Logger manual page to remove reference to RandomAccessFile appender
> * Rewrite section on _Latency_
> ** The histogram shows service time (more useful for users is response time: service time + wait time).
> ** Bar chart diagram on "average latency" is nonsense. Latency is not a normal distribution so terms like "average latency" don't make sense. Remove this. (A histogram showing the full range of percentiles _does_ make sense.)
> ** Bar chart diagram with max of 99.99% of observations is better than average but still has large drawbacks: this is service time (omitting the crucial wait time) and how high are the peaks in the 0.01% we did not report? Better to remove this and instead show a histogram with the full range of percentages.
> *Performance Page*
> # Briefly explain about various aspects of "performance": peak measured throughput (what kind of bursts can we deal with?), sustained throughput, and response time (service time + wait time).
> # Then show how Log4j 2 compares to the alternatives (Logback, Log4j-1.2 and JUL) on all these three performance dimensions.
> # Finally, document some performance trade-offs for Log4j 2 functionality.
> *2. Comparison to alternative logging libraries*
> Link to Async Loggers page for bursty logging.
> Clarify that Async Appender exists to minimize dependencies but should be avoided if performance is a concern. Async Appender is NOT the default and should NOT be used for benchmarking. (I found [this loggly article|https://www.loggly.com/blog/benchmarking-java-logging-frameworks/] very frustrating in that respect.) Should probably also clarify that any benchmark that tests with only one thread doing logging is of limited use.
> For various appenders, compare Log4j2 to alternatives with regards to max sustained throughput (and separately, response time).
> * [File Appender max sustained thoughput|https://issues.apache.org/jira/browse/LOG4J2-1297?focusedCommentId=15256490&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15256490]
> * Socket appender (TCP/UDP)
> * Syslog appender (TCP/UDP)
> *3. Log4j 2 functionality performance trade-offs*
> * including location
> * Cost of various layouts (HTML, XML, CSV, Pattern)
> * Cost of various Pattern Layout options
> * Cost of various appenders (File, RandomAccess File, MemoryMapped File, Console, Rewrite, other?) TODO: decide on layout for these tests.
> * Cost of various APIs/wrappers (SLF4J, Log4j1, JUL, Commons Logging)
> * JDBC appenders? - different JDBC drivers and target databases may have very different performance. May become a big project. We could do a quick comparison of the JDBC appender to the JDK Derby DB compared against FileAppender just to get an idea of max sustained throughput?
> -------------------
> Of the existing Performance page sections:
> * Briefly mention that disabled logging has no measurable cost, but de-emphasize this section by moving it down the page.
> * Parameterized messages: use these JMH [benchmark results|https://issues.apache.org/jira/browse/LOG4J2-1278?focusedCommentId=15216236&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15216236]? (Looks like parameterized messages are currently quite expensive...)
> * I like the part about the filters because it a) compares Log4j 2 to Logback and b) considers multithreaded applications. I'll turn this into a JMH test and show the result as a bar chart.
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