Java thread start time

Question

Is it possible to retrieve the start time of a given java thread within the JVM?

I have a thread dump and am looking at some problematic threads which I would like to correlate to a specific operations in the application log using time.

Answer 1

There is no method in the Java API that provides you this information. Besides, it may not be up useful anyways. Consider the case of a thread pool where thread creation is not necessarily tied to application-level events.

If you are in full control of thread creation, then you may attach a thread-local variable to the thread that records its creation time.

Answer 2

Yes, it is possible if you are running Oracle JDK / OpenJDK on Linux.

The idea is to find native thread id (TID) and then look at the modification time of /proc/JAVA_PID/task/TID pseudo file.

If you have a Thread Dump, then this is trivial: the native thread id would be printed by the thread header.

For example, Java process PID is 2086. You type

$ jstack 2086

and get a stack trace with the following thread of interest:

"Thread-26" prio=10 tid=0x00007f96c80c2800 nid=0x86a waiting on condition [0x00007f96c0ff2000]
   java.lang.Thread.State: TIMED_WAITING (sleeping)

Where nid=0x86a is the native thread ID. 0x86a = 2154, so you'd like to explore task 2154 of the process 2086:

$ ls -ld /proc/2086/task/2154
dr-xr-xr-x 6 user user 0 Mar 10 23:12 /proc/2086/task/2154
                         ^^^^^^^^^^^^
                         the thread start time

Answer 3

尝试使用“ps -p $ pid -wLo lwp，lstart”