As a related project, we could fix the JDK so that threads blocked in IO operations would be much more likely to also report a thread state of BLOCKED.
Martin On Fri, Aug 13, 2010 at 09:59, Doug Lea <d...@cs.oswego.edu> wrote: > Sorry for the long delay on this... > > > On 07/15/10 23:43, Mandy Chung wrote: > >> I think making Thread.threadStatus a volatile field and using >> JVMTI_JAVA_LANG_THREAD_STATE_MASK to convert Thread.threadStatus to >> Thread.State >> enum would be a good solution. >> >> >> It'd be great if Doug can do the experiment and evaluate the performance >> impact. >> If you want me to prototype the jdk change, let me know and I should be >> able to >> make some time to do it next week. >> >> > I did an equivalent experiment (of just directly accessing > threadState via Unsafe.getIntVolatile and comparing it to > cached values) and it was about 14X faster. So anything > along these lines would be grat. That said, I decided not > to try to rely on getState in the near term. (Among other > reasons, it does not usually reflect IO blockage.) So this > is off the critical path for now. But someday someone is sure > to run into similar performance issues unless implementation > is improved. > > -Doug > >
