Major Description
Class org.apache.wicket.page.PageAccessSynchronizer uses a global lock (org.apache.wicket.page.PageAccessSynchronizer.semaphore) that is needed e.g. when a new instance of a Page is created or when an instance of a page is retrieved, The lock is global and becomes quickly contented. When testing with two parallel threads, about 20% of all statistical stack samples waited for the lock, with four parallel threads about 50%.
The stack waiting for the lock is
at org.apache.wicket.page.PageAccessSynchronizer.lockPage(PageAccessSynchronizer.java:119)
at org.apache.wicket.page.PageAccessSynchronizer$1.getPage(PageAccessSynchronizer.java:187)
called either by
at org.apache.wicket.Page.dirty(Page.java:327)
as part of the Page ctor, or by
at org.apache.wicket.DefaultMapperContext.getPageInstance(DefaultMapperContext.java:117)
when retrieving page.
Some threads' stacks:
waiting on (a java.lang.Object@0xHEXADDR)
at org.apache.wicket.page.PageAccessSynchronizer.lockPage(PageAccessSynchronizer.java:119)
at org.apache.wicket.page.PageAccessSynchronizer$1.getPage(PageAccessSynchronizer.java:187)
at org.apache.wicket.DefaultMapperContext.getPageInstance(DefaultMapperContext.java:117)
at org.apache.wicket.request.handler.PageProvider.getPageInstance(PageProvider.java:246)
at org.apache.wicket.request.handler.PageProvider.getPageInstance(PageProvider.java:159)
at org.apache.wicket.request.handler.ListenerInterfaceRequestHandler.getPage(ListenerInterfaceRequestHandler.java:89)
at org.apache.wicket.request.handler.ListenerInterfaceRequestHandler.respond(ListenerInterfaceRequestHandler.java:141)
at org.apache.wicket.request.cycle.RequestCycle$HandlerExecutor.respond(RequestCycle.java:718)
at org.apache.wicket.request.RequestHandlerStack.execute(RequestHandlerStack.java:63)
at org.apache.wicket.request.cycle.RequestCycle.processRequest(RequestCycle.java:212)
at org.apache.wicket.request.cycle.RequestCycle.processRequestAndDetach(RequestCycle.java:253)
at org.apache.wicket.protocol.http.WicketFilter.processRequest(WicketFilter.java:138)
at org.apache.wicket.protocol.http.WicketFilter.doFilter(WicketFilter.java:194)
....
at java.lang.Object.wait(Native Method)
waiting on (a java.lang.Object@0xHEXADDR) at org.apache.wicket.page.PageAccessSynchronizer.lockPage(PageAccessSynchronizer.java:119)
at org.apache.wicket.page.PageAccessSynchronizer$1.touchPage(PageAccessSynchronizer.java:194)
at org.apache.wicket.Page.dirty(Page.java:327)
at org.apache.wicket.Page.init(Page.java:770)
at org.apache.wicket.Page.<init>(Page.java:223)
at org.apache.wicket.Page.<init>(Page.java:202)
at org.apache.wicket.markup.html.WebPage.<init>(WebPage.java:99)
at x.y.z.page.base.Page.<init>(Page.java:100)
at x.y.z.page.base.ControllerBasedPage.<init>(ControllerBasedPage.java:41)
....
at java.lang.Object.wait(Native Method)
waiting on (a java.lang.Object@0xHEXADDR) at org.apache.wicket.page.PageAccessSynchronizer.lockPage(PageAccessSynchronizer.java:119)
at org.apache.wicket.page.PageAccessSynchronizer$1.touchPage(PageAccessSynchronizer.java:194)
at org.apache.wicket.Page.dirty(Page.java:327)
at org.apache.wicket.Page.init(Page.java:770)
at org.apache.wicket.Page.<init>(Page.java:223)
at org.apache.wicket.Page.<init>(Page.java:202)
at org.apache.wicket.markup.html.WebPage.<init>(WebPage.java:99)
at x.y.z.page.base.Page.<init>(Page.java:100)
at x.y.z.page.base.ControllerBasedPage.<init>(ControllerBasedPage.java:41)
at x.y.z.page.NavigationAndContent.<init>(NavigationAndContent.java:43)
at x.y.z.page.MailDetail.<init>(MailDetail.java:84)
x.y.z.page.login.Login.<init>-wicket.Page.<init>-wicket.page.PageAccessSynchronizer.lockPage-WAIT_FOR_LOCK
at java.lang.Object.wait(Native Method)
waiting on (a java.lang.Object@0xHEXADDR) at org.apache.wicket.page.PageAccessSynchronizer.lockPage(PageAccessSynchronizer.java:119)
at org.apache.wicket.page.PageAccessSynchronizer$1.touchPage(PageAccessSynchronizer.java:194)
at org.apache.wicket.Page.dirty(Page.java:327)
at org.apache.wicket.Page.init(Page.java:770)
at org.apache.wicket.Page.<init>(Page.java:223)
at org.apache.wicket.Page.<init>(Page.java:202)
at org.apache.wicket.markup.html.WebPage.<init>(WebPage.java:99)
at x.y.z.page.base.Page.<init>(Page.java:100)
at x.y.z.page.login.Login.<init>(Login.java:23)
.....
at java.lang.Object.wait(Native Method)
waiting on (a java.lang.Object@0xHEXADDR) at org.apache.wicket.page.PageAccessSynchronizer.lockPage(PageAccessSynchronizer.java:119)
at org.apache.wicket.page.PageAccessSynchronizer$1.touchPage(PageAccessSynchronizer.java:194)
at org.apache.wicket.Page.dirty(Page.java:327)
at org.apache.wicket.Page.init(Page.java:770)
at org.apache.wicket.Page.<init>(Page.java:223)
at org.apache.wicket.Page.<init>(Page.java:202)
....
at java.lang.Object.wait(Native Method)
at org.apache.wicket.page.PageAccessSynchronizer.lockPage(PageAccessSynchronizer.java:119)
at org.apache.wicket.page.PageAccessSynchronizer$1.touchPage(PageAccessSynchronizer.java:194)
at org.apache.wicket.Page.dirty(Page.java:327)
at org.apache.wicket.Page.init(Page.java:770)
at org.apache.wicket.Page.<init>(Page.java:223)
at org.apache.wicket.Page.<init>(Page.java:202)
.....