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Posted to dev@hc.apache.org by "Oleg Kalnichevski (JIRA)" <ji...@apache.org> on 2016/11/19 18:46:59 UTC
[jira] [Updated] (HTTPCORE-433) Setting validateAfterInactivity to
1ms increases lock contention in AbstractConnPool
[ https://issues.apache.org/jira/browse/HTTPCORE-433?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Oleg Kalnichevski updated HTTPCORE-433:
---------------------------------------
Fix Version/s: (was: 5.0)
5.0-alpha2
4.4.6
> Setting validateAfterInactivity to 1ms increases lock contention in AbstractConnPool
> ------------------------------------------------------------------------------------
>
> Key: HTTPCORE-433
> URL: https://issues.apache.org/jira/browse/HTTPCORE-433
> Project: HttpComponents HttpCore
> Issue Type: Bug
> Components: HttpCore
> Affects Versions: 4.4.4
> Reporter: Sergiu Prodan
> Fix For: 4.4.6, 5.0-alpha2
>
> Attachments: httpclient_thread_dump, threads_when_inactivity_set_to_1.png, threads_when_inactivity_set_to_2000.png
>
>
> This issue was observed after upgrading to httpclient v4.5.2 and httpcore v4.4.4.
> When configuring the PoolingHttpClientConnectionManager, I have set validateAfterInactivity to 1ms as this is the only way of maintaining the old behaviour, i.e. checking every connection if is stale before using it.
> I have observed a performance degradation under high load when the httpclient is shared between multiple threads. This httpclient is used only for one route.
> After taking a thread dump, one thing that got my attention was several threads waiting for same ReentrantLock instance while trying to AbstractConnPool#getPoolEntryBlocking/AbstractConnPool#release. The ReentrantLock instance in question was owned by another thread performing CPool#validate.
> It seems to me that performing this stale check inside the region protected by this lock is unnecessary and also induces a big performance hit when using the httpclient from multiple threads.
> I've atached a thread dump of a test application that reproduces this behaviour. ReentrantLock in question in this thread dump is 0x0000000706e8b9a8 and is owned by Thread-4.
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