Experimental feature; may or may not be useful. Dump the current value of half a dozen VM mutexes. This will tell us if they're unlocked, locked, or contended-for at the point somebody does a thread dump. For example, when the GC notices the HeapWorker watchdog has expired: I/dalvikvm( 2828): DALVIK THREADS: I/dalvikvm( 2828): (mutexes: tll=0 tsl=0 tscl=0 ghl=1 hwl=1 hwll=0) In this case, gcHeapLock and heapWorkerLock are held, the rest are not. If this turns out to be useful we can put more effort into the output format. The pthread lib doesn't insert the thread ID unless you're using recursive or errorcheck mutexes, which (for performance reasons) we try not to use. Change-Id: I272534d8c9db6340cfc23bfdddb47beefc2efbfb