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Run a multi-thread program in 2.4 kernal, I can see each thread has its own PID in top command, while in 2.6 kernal, it seems all threads share a unique ...
  1. 09-03-2009 #1
    fisherg
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    Thread ID in Linux

    Run a multi-thread program in 2.4 kernal, I can see each thread has its own PID in top command, while in 2.6 kernal, it seems all threads share a unique ID, since in top command, I can see only one PID for my program.

    Is this correct?
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  2. 09-04-2009 #2
    Rubberman
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    The 2.6 kernel has integrated threading much more thoroughly than 2.4 and earlier kernels. Yes, it is correct in that a thread id is not a process id in 2.6, even though each thread can be scheduled separately, allowing each thread to run on a different CPU/core.
    Sometimes, real fast is almost as good as real time.
    Just remember, Semper Gumbi - always be flexible!
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  3. 09-04-2009 #3
    fisherg
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    Thanks for your reply.

    In Top command window, I can only get the single PID for all threads, is there any tool I can check thread ID for each thread?
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  4. 09-04-2009 #4
    Rubberman
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    You can get thread info from the ps command with the -L option. See the ps man pages for more information. Also, you can get thread info from top with the 'H' toggle.
    Sometimes, real fast is almost as good as real time.
    Just remember, Semper Gumbi - always be flexible!
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  5. 09-06-2009 #5
    cosmicmittens
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    You can associate thread id with master pid using pstree -p. It's useful for visual display.
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  6. 09-07-2009 #6
    fisherg
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    Is there any way I can print out the current process/thread info on each cpu in my own program?
    I guess there may be some function calls I can use in Linux, but I am not sure.
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