Portlet Load monitoring is a portlet filter that allows portal administrators to protect their portal by defining a maximum number of concurrent requests and an average response time allowed for a JSR 168 or JSR 286 portlet. If the portlet exceeds either the defined maximum number of concurrent requests, or the average response time, then Portlet Load Monitoring will no longer allow further requests to the portlet. Instead, portal renders the portlet as unavailable and the portlet code is no longer called for further requests. This way, your portal installation is protected from non responsive portlets to consume more and more threads.
This requires WebSphere Portal 126.96.36.199 or 6.15 or higher, as well as APAR 05689, which is included in cumulative fix 3 (CFPM09968) or available on top of CF2. It is already included in WepSphere Portal 7.0.
Version 188.8.131.52 (published on Oct 26, 2010): APAR PM21203: Fixed problem that Portlet Load Monitoring does not reduce the request counter if a portlet throws an exception
Version 184.108.40.206 (published on Aug 9, 2010): Fixed problem that Portlet Load Monitoring does not evaluate portlet preferences set in portlet.xml