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https://issues.apache.org/jira/browse/TAP5-2461?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14354815#comment-14354815
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Michael Mikhulya commented on TAP5-2461:
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I also worried about creating new caches and increasing memory consumption.
Thanks to your suggestion I found a way to reuse existing cache. So no new
caches are introduced.
Please look changes in patch.
Performance measurements are following:
|| Concurrency Level || Requests per second (BEFORE) ||Requests per second
(AFTER) ||
| 8 | 490.31| 517.56 |
So we have 5% gain.
Test was done on processor with 4 physical cores each containing 2 virtual
cores (hyper threading).
I believe gain should be even better on server processor with many cores.
> Lock contention on ZipFile.getEntry
> -----------------------------------
>
> Key: TAP5-2461
> URL: https://issues.apache.org/jira/browse/TAP5-2461
> Project: Tapestry 5
> Issue Type: Bug
> Components: tapestry-core, tapestry-ioc
> Reporter: Michael Mikhulya
> Labels: performance
> Attachments: 0001-Get-rid-of-lock-contention-on-ZipFile.getEntry.patch
>
>
> Following locks are very very frequent on production environment.
> {noformat}
> "catalina-exec-244" #9143 daemon prio=5 os_prio=0 tid=0x00007fb350209800
> nid=0x4b0a waiting for monitor entry [0x00007fb1a76b3000]
> java.lang.Thread.State: BLOCKED (on object monitor)
> at java.util.zip.ZipFile.getEntry(ZipFile.java:309)
> - locked <0x00000006490a34a0> (a java.util.jar.JarFile)
> at java.util.jar.JarFile.getEntry(JarFile.java:240)
> at java.util.jar.JarFile.getJarEntry(JarFile.java:223)
> at sun.misc.URLClassPath$JarLoader.getResource(URLClassPath.java:841)
> at sun.misc.URLClassPath$JarLoader.findResource(URLClassPath.java:819)
> at sun.misc.URLClassPath.findResource(URLClassPath.java:176)
> at java.net.URLClassLoader$2.run(URLClassLoader.java:557)
> at java.net.URLClassLoader$2.run(URLClassLoader.java:555)
> at java.security.AccessController.doPrivileged(Native Method)
> at java.net.URLClassLoader.findResource(URLClassLoader.java:554)
> at java.lang.ClassLoader.getResource(ClassLoader.java:1093)
> at
> org.apache.catalina.loader.WebappClassLoaderBase.getResource(WebappClassLoaderBase.java:1042)
> at
> org.apache.tapestry5.ioc.internal.util.ClasspathResource.resolveURL(ClasspathResource.java:79)
> at
> org.apache.tapestry5.ioc.internal.util.ClasspathResource.toURL(ClasspathResource.java:61)
> at
> org.apache.tapestry5.ioc.internal.util.AbstractResource.computeExists(AbstractResource.java:236)
> at
> org.apache.tapestry5.ioc.internal.util.AbstractResource.exists(AbstractResource.java:218)
> at
> org.apache.tapestry5.ioc.internal.util.AbstractResource.findLocalizedResource(AbstractResource.java:177)
> at
> org.apache.tapestry5.ioc.internal.util.AbstractResource.populateLocalizationCache(AbstractResource.java:159)
> at
> org.apache.tapestry5.ioc.internal.util.AbstractResource.forLocale(AbstractResource.java:136)
> at
> org.apache.tapestry5.internal.services.AssetSourceImpl.getLocalizedAssetFromResource(AssetSourceImpl.java:134)
> at
> org.apache.tapestry5.internal.services.AssetSourceImpl.getAssetInLocale(AssetSourceImpl.java:107)
> at
> org.apache.tapestry5.internal.services.AssetSourceImpl.getAsset(AssetSourceImpl.java:87)
> at $AssetSource_ef3168bbfb42e.getAsset(Unknown Source)
> at
> org.apache.tapestry5.internal.services.javascript.CoreJavaScriptStack.getJavaScriptLibraries(CoreJavaScriptStack.java:154)
> {noformat}
> I investegated a reason of issue.
> Since tapestry-5.3.4 {{AbstractResource.forLocale}} returns the cached result.
> The problem is that cache is not used in this case.
> For example:
> {code:title=AssetSourceImpl.java}
> private Resource findResource(Resource baseResource, String path)
> {
> assert path != null;
> int colonx = path.indexOf(':');
> if (colonx < 0)
> {
> Resource root = baseResource != null ? baseResource :
> prefixToRootResource.get(AssetConstants.CLASSPATH);
> return root.forFile(path);
> ...
> {code}
> Here each time new resource is created with empty cache.
> So when we call {{AbstractResource.forLocale}} it is forced to call
> {{AbstractResource.findLocalizedResource}}.
> I suggest to add simple caches (ConcurrentHashMap) in {{ClasspathResource}}
> and {{ContextResource}} and use this cache inside {{newResource}} method.
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