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    SubjectRe: [announce] Performance Counters for Linux, v6
    Ingo Molnar wrote:
    > We are pleased to announce version 6 of our performance counters subsystem
    > implementation. The shortlog, diffstat and the combo patch can be found
    > below. The combo patch against latest -git (2.6.29-rc2) can be also found
    > at:
    >
    > http://people.redhat.com/mingo/perfcounters/perfcounters-v6-v2.6.29-rc2.patch
    >
    > It's also available in tip/master at:
    >
    > http://people.redhat.com/mingo/tip.git/README
    >
    > There are many changes in the v6 release:
    >
    > - PowerPC performance counters support from Paul Mackerras, for POWER6
    > and for the PPC970 family.
    >
    > - ioctl API to disable/enable individual counters and groups without
    > closing their fd. This can be useful for libraries, ad-hoc
    > instrumentation and PAPI support.
    >
    > - 'pinned' and 'exclusive' counter attributes - for those
    > applications that want to influence counter scheduling explicitly.
    >
    > - The 'perfstat' utility (ex 'timec') has been updated:
    >
    > http://people.redhat.com/mingo/perfcounters/perfstat.c
    >
    > - 'kerneltop' (easy-to-use text mode NMI profiler) has been updated:
    >
    > http://people.redhat.com/mingo/perfcounters/kerneltop.c
    >
    > - Merged to latest mainline
    >
    > - Various fixes and other updates
    >
    > Ingo

    I'm not sure if this is the right place to propose such a thing, but I
    think it would be very valuable to have a standardized user-side library
    to accompany this addition to the kernel.

    In particular, as a starting place for the discussion, I'd like to see
    functions in it that are very similar to a subset of what is currently
    in libpfm. Specifically, I'd like to see the following functions (with
    the names changed to pcl_* perhaps):

    extern pfm_err_t pfm_find_event(const char *str, unsigned int *idx);
    extern pfm_err_t pfm_find_event_bycode(int code, unsigned int *idx);
    extern pfm_err_t pfm_find_event_bycode_next(int code, unsigned int start,
    unsigned int *next);
    extern pfm_err_t pfm_find_event_mask(unsigned int event_idx, const char
    *str,
    unsigned int *mask_idx);
    extern pfm_err_t pfm_find_full_event(const char *str, pfmlib_event_t *e);

    extern pfm_err_t pfm_get_max_event_name_len(size_t *len);

    extern pfm_err_t pfm_get_num_events(unsigned int *count);
    extern pfm_err_t pfm_get_num_event_masks(unsigned int event_idx,
    unsigned int *count);
    extern pfm_err_t pfm_get_event_name(unsigned int idx, char *name,
    size_t maxlen);
    extern pfm_err_t pfm_get_full_event_name(pfmlib_event_t *e, char *name,
    size_t maxlen);
    extern pfm_err_t pfm_get_event_code(unsigned int idx, int *code);
    extern pfm_err_t pfm_get_event_mask_code(unsigned int idx,
    unsigned int mask_idx,
    unsigned int *code);
    extern pfm_err_t pfm_get_event_description(unsigned int idx, char **str);
    extern pfm_err_t pfm_get_event_code_counter(unsigned int idx, unsigned
    int cnt,
    int *code);
    extern pfm_err_t pfm_get_event_mask_name(unsigned int event_idx,
    unsigned int mask_idx,
    char *name, size_t maxlen);
    extern pfm_err_t pfm_get_event_mask_description(unsigned int event_idx,
    unsigned int mask_idx,
    char **desc);


    Now, since it's not clear right now how unit masks are going to be
    handled in your proposal, I'm not sure the that *_event_mask_* functions
    are applicable, but I think something that fills that function will be
    needed.

    Architectures that have need for additional functionality should be free
    to add arch-specific functions.

    Full descriptions of these functions can be found in the man pages of
    the libpfm documentation.

    Any thoughts on this? Do you already have a user library structure in mind?

    --
    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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