[MJAR-140] Performance degredation

[jira-importer]

Eran Harel opened MJAR-140 and commented

I migrated maven to version 3.0.1 in order to utilize the parallel build experimental feature.
As a result I get the following warning:

[WARNING] *****************************************************************
[WARNING] * Your build is requesting parallel execution, but project      *
[WARNING] * contains the following plugin(s) that are not marked as       *
[WARNING] * @threadSafe to support parallel building.                     *
[WARNING] * While this /may/ work fine, please look for plugin updates    *
[WARNING] * and/or request plugins be made thread-safe.                   *
[WARNING] * If reporting an issue, report it against the plugin in        *
[WARNING] * question, not against maven-core                              *
[WARNING] *****************************************************************
[WARNING] The following plugins are not marked @threadSafe in DataBuilder:
[WARNING] org.apache.maven.plugins:maven-eclipse-plugin:2.8
[WARNING] org.apache.maven.plugins:maven-jar-plugin:2.2
[WARNING] *****************************************************************

I upgraded the maven-jar-plugin to the latest version (2.3.1), and the message is gone, but now the builds take much longer: minutes added!!!
The build takes about x 1.5 longer now.

I also compared the maven 3 parallel build time with the new jar-plugin VS a serial build with the old 2.2 plugin version I had. The results are that same, while when using the parallel build with the 2.2 plugin I see a significant ~30% performance boost.

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Affects: 2.3, 2.3.1

1 votes, 0 watchers

[jira-importer]

Eran Harel commented

BTW, the 2.3.1 jar-plugin version has the same effect on maven 2.2.1 if it helps.

[jira-importer]

Dennis Lundberg commented

Can you please try with version 2.3 of the plugin to see what results you get?

[jira-importer]

Eran Harel commented

2.2 results:

[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2:25.773s
[INFO] Finished at: Thu Dec 30 12:24:16 IST 2010
[INFO] Final Memory: 1001M/1575M

2.3 results

[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 4:30.299s
[INFO] Finished at: Thu Dec 30 15:06:08 IST 2010
[INFO] Final Memory: 1014M/1831M
[INFO] ------------------------------------------------------------------------

[jira-importer]

Kristian Rosenvold commented

It would seem to me like this degradation occured when plexus-archiver switched to using PlexusIoProxyResourceCollection (0c17e83ae31786fd96f24d7ed5484e0e5df99a47) which possibly retrieves quite a lot of information we dont use. Especially on Linux this can be bad since plexus-io still uses forks to determine file attributes, which I am still not sure if we use/need.

[jira-importer]

Erez Mazor commented

Any updates on this issue?

[jira-importer]

Kristian Rosenvold commented

Yes, but it's not a simple answer.

The update to PlexusIoResourceCollection was done to achieve file attribute correctness. So the incorrect behaviour was fast but the correct behaviour is slower.

But all is not entirely lost. I have published pleus-archiver 2.0, plexus-io 2.0 and plexus-utils 3.0. If you add all of these to your plugin dependencies you will get an improvement in performance. To get back to the "original" speed you will actually have to use java 1.7. plexus-io 2.0 supports native file attributes through the java 1.7 api's. So with java 1.7 you should see little or no difference in performance from 2.2. For java 1.5/1.6, plexus-io 2.0 now forks the two "ls" forks in parallel, which should help some on the observed slowdown.

The slowdown affects all posix compliant systems.

[jira-importer]

Kristian Rosenvold commented

I'm closing this as fixed with the 2.4 release. It is not /as/ fast as 2.3 (unless you use java7), but it's at least better. And correctnes is better than fast.

[jira-importer]

Eran Harel commented

When will the 2.3.2 / 2.4 artifacts be available in the maven repository?

[jira-importer]

Kristian Rosenvold commented

2.3.2 is available now