Second, FWIW. Our users are constantly baffled as to why all of their blocked-on-epoll threads are listed as RUNNABLE.
Jeremy On Fri, Aug 13, 2010 at 10:18 AM, Martin Buchholz <marti...@google.com> wrote: > 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 >> > >
