Threads Oversleep for seconds

Question

Hi,
I have a problem that in my application threads tend to oversleep for long periods of time.
I set the sleeping time for 1 second, but the thread may wakeup after 13 seconds.
I also tried to use quartz scheduling and TimerTask with similar results.
The basic run is as follows:
while(true) {
   try{
     Thread.sleep(1000);
   } catch (InterruptedException e){;     }
  }The application consumes about 2GB of memory and has about 100 threads dedicated to TCP communication at all times, but the load average on the Linux machine doesn't pass 2.00
I am running my application on a strong Linux machine with 12 CPUs and 16GB of RAM with 32-bit JVM.
Any idea what can be causing this?
thanks,
Roy

Answer 1

I have check the CPU load and it appear to be heavy.
Perhaps its worth to note that that are about 150 threads in the application. 100 of them are dedicated to read TCP connection (in block mode).
another curious thing i have noted is that in jstack all the threads appear to have priority of 10 but when i query the treads in the code they have normal priority (5):
"Thread-19" prio=10 tid=0x0abc7800 nid=0x3802 runnable [0x12a5c000]
"Attach Listener" daemon prio=10 tid=0x0ae05000 nid=0x366a waiting on condition [0x00000000]
"Timer-3" daemon prio=10 tid=0x0a494800 nid=0x3600 in Object.wait() [0x129ba000]
"Thread-15" prio=10 tid=0x0a493400 nid=0x35ff sleeping[0x12a0b000]
"GC Daemon" daemon prio=10 tid=0x0a456800 nid=0x35f9 in Object.wait() [0x12c5c000]
"RMI RenewClean-[172.16.4.215:45120]" daemon prio=10 tid=0x0a455800 nid=0x35f8 in Object.wait() [0x12cad000]
"RMI Scheduler(0)" daemon prio=10 tid=0x0a45a000 nid=0x35f7 waiting on condition [0x12cfe000]
"TimeIntervalListener" prio=10 tid=0x0a424800 nid=0x3565 waiting on condition [0x131fe000]
is jstack inaccurate?