Comment 256 for bug 595047

Hi Ben,

Thank you for the clarification. I think I was really lost on this. I expected the process to wait while IO but then it's supposed that the rest of the system should take the rest of the processor power while it's not. The system seems to hang until IO stops.

So I think best way to proceed is to start to discard problems.

I propose to start with:

    I will try to do CPU intensive with no IO task while other process will write a file with no CPU intensive to check if the first process take the same time to execute under high IO or not.
            Process 1: CPU / No IO
            Process 2: High UI / No CPU
    And measure times...

    Should this test trigger the problem? As no IO for process 1 it should finish almost in the same time than under no load at all. Right?

    Can we discard a ext3 related problem? Test case (Test writing files 1 thread, over ext3 and ext4, reiser, etc) and observe responsivness.

    Can we track if this is a fsync problem? How (commands, test case)?

    How can we test this without making filesystem take part on the tests?

    Can we show differences between kernel 2.6.16 and >=2.6.28? (I will do this today)

    How to measure responsiveness? Can we put a numeric value to this?

Thank you all.