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    SubjectRe: perf_events: zero time running and enabled, but non-zero count
    Anyone had a chance to look at this test case yet?

    Regards,

    - Corey

    Corey Ashford wrote:
    > On 10/23/2009 01:57 PM, Ingo Molnar wrote:
    >>
    >> * Corey Ashford<cjashfor@linux.vnet.ibm.com> wrote:
    >>
    >>>> Btw., you might want to consider putting such testcases into a new
    >>>> 'perf test' kind of utility (under tools/perf/builtin-test.c) that
    >>>> does various tests such as reading a count and validating the
    >>>> time-running/time-enabled values - so that we can see any bugs
    >>>> directly.
    >>>
    >>> I'll see if I can put the test case in some sort of acceptable format
    >>> like that. Maybe we can use this one test case as the starting point
    >>> for builtin-test.c.
    >>
    >> Yeah. Feel free to add just something minimal that solves your problem.
    >> Others will add their testcases too i'm sure, once the basic command is
    >> there.
    >>
    >> Ingo
    >
    > Hi Ingo and Paul,
    >
    > I followed the directions Ingo provided for getting the -tip tree and
    > then attempted to build the perf tool that's in it and it doesn't build.
    > I'm getting this error on a Power5 box:
    >
    > ../../lib/find_next_bit.c: In function ‘ext2_swabp’:
    > ../../lib/find_next_bit.c:168: warning: passing argument 1 of
    > ‘__swab64p’ from incompatible pointer type
    > make: *** [util/find_next_bit.o] Error 1
    >
    > I looked at the code and it looks ok to me. There's a cast from an
    > "unsigned long *" to a "unsigned long long *", but those types should be
    > of the same size (in -m64 mode), so I don't know why this is failing.
    >
    > Some good news is that I have created a simple test case which
    > demonstrates the bug, but I haven't formulated it in the builtin-test.c
    > format yet, since I have been able to build perf.
    >
    > If you toss the attached file into the perf source directory and compile
    > it as follows:
    >
    > gcc -m64 -o petb perf_events_time_bug.c -lrt
    >
    > it will show the error:
    > % ./petb
    > [0] = 1
    > [1] = 0 <- time enabled
    > [2] = 0 <- time running
    > [3] = 4559d1f8
    > [4] = 1
    > test failed!
    >
    > perf_events_time_bug.c -lrt
    >
    > If you compile it with:
    >
    > gcc -DDO_DISABLE -m66 -o petb perf_events_time_bug.c -lrt
    >
    > This will disable the event before reading it and then you will get the
    > correct times.
    >
    > % ./petb
    > [0] = 1
    > [1] = 2a50c1c8 <- time enabled
    > [2] = 2a50c1c8 <- time running
    > [3] = 460dea97
    > [4] = 2
    > test passed!
    >

    --
    Regards,

    - Corey

    Corey Ashford
    Software Engineer
    IBM Linux Technology Center, Linux Toolchain
    Beaverton, OR
    503-578-3507
    cjashfor@us.ibm.com

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