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Problem Report 0201 Details

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Report 0201 Actions

    Problem Report Number 0201
    Submitter's Classification Test Suite problem
    State Resolved
    Resolution Test Suite Deficiency (TSD)
    Problem Resolution ID TSD.X.0201
    Raised 1995-01-05 08:00
    Updated 2003-03-13 08:00
    Published 1995-01-18 08:00
    Product Standard Internationalised System Calls and Libraries (XPG4)
    Certification Program The Open Brand certification program
    Test Suite VSX4 version 4.3.4
    Test Identification XOPEN.os/time/clock 2
    Problem Summary TSD4.201 This test is making an incorrect assumption of the clock() function. the XPG4 standard does not say that clock() should report the CPU time of child processes: "DESCRIPTION The {clock()} function retu...
    Problem Text
    This test is making an incorrect assumption of the clock() function.
    the XPG4 standard does not say that clock() should report the CPU time
    of child processes:

    "DESCRIPTION

    The {clock()} function returns the implementation's best
    approximation to the processor time used by the process since the
    beginning of an implementation-dependent time related only to the
    process invocation."

    The phrase "used by the process" is key. We believe the standard says
    that if clock() returns the time used by child processes, it would be
    working incorrectly.

    The test should not be using the tms_cutime components of the tms
    structure returned by times() to arrive at an independant CPU time
    approximation.
    Test Output
    /tset/XOPEN.os/time/clock/T.clock 2 Failed

    Test Description:
    The time reported is the sum of user and system times of the calling
    process and terminated child processes for which it has executed
    wait() or system().
    (See PARAMETERS : VSX_CLOCK_ERR below)

    Test Strategy:
    CALL clock() and times(), saving CPU times given by times()
    EXECUTE user and system code, using use_time() and sys_call()
    CREATE child process
    EXECUTE user and system code, using use_time() and sys_call()
    VERIFY that the value returned by clock() agrees with the increase in
    CPU times given by times() to within VSX_CLOCK_ERR percent

    Test Information:
    CPU time used as given by clock() does not correspond to value given by
    times() within tolerance limits
    CPU time as given by times is 140000 microseconds
    CPU time as given by clock is 99618 microseconds

    Review Information

    Review Type TSMA Review
    Start Date null
    Completed null
    Status Complete
    Review Recommendation No Resolution Given
    Review Response
    The test suite aligns with the statements in XPG3 rather than those
    in XSH4. The CHANGE HISTORY section of XSH4 states that the changes
    made in the Issue 4 update are "functionally equivalent to Issue 3".

    This statement seems to be misleading since in XPG3 it states that:

    "The clock() function returns the amount of CPU time used since the
    first call to clock()"

    and in XSH4 it states that:

    "The clock() function returns .... the processor time used since the
    beginning of ...... time related only to the process invocation."

    The current code follows the strategy defined for XPG3 and needs to be
    aligned with the XSH4 description.

    A permanent waiver is recommended on the basis of a test suite deficiency.

    Review Type SA Review
    Start Date null
    Completed null
    Status Complete
    Review Resolution Test Suite Deficiency (TSD)
    Review Conclusion
    This is an agreed Test Suite Deficiency.

    Problem Reporting System Options:

     

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