[SCM] systemtap: system-wide probe/trace tool branch, master, updated. release-0.9.7-198-gf517ee2

[jistone at sourceware dot org]

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- Log -----------------------------------------------------------------
commit f517ee24c58413f7de89ede71c728579c12ace5b
Author: Josh Stone <jistone@redhat.com>
Date:   Mon Jun 8 16:37:00 2009 -0700

    Remove dwflpp::default_name
    
    It was just a basic NULL check, but creating its string temporaries was
    causing a fair slowdown.  Removing this function and adjusting the
    callers shaves ~5% off the syscall.* elaboration time.

commit 0e14e0793ffb891bccd465cf518480685e3cd49e
Author: Josh Stone <jistone@redhat.com>
Date:   Mon Jun 8 15:36:42 2009 -0700

    Let query_module abort early for simple matches
    
    query_module was already returning DW_CB_ABORT when a simple match was
    found, but dwflpp::iterate_over_modules was ignoring that and instead
    forcing the module loop to restart.  The only way out of the loop was
    with the pending_interrupts flag, which is only for signalled
    interrupts.
    
    Now iterate_over_modules will only attempt the dwfl_getmodules loop
    once, since that loop will only abort if the CB returns DW_CB_ABORT.
    Then query_module is also modified to return ABORT if pending_interrupts
    is flagged.
    
    My trusty test, stap -l syscall.*, is nearly 2x faster with this change.
    Empirically, I found that the kernel object is always the first "module"
    returned, so the syscall probepoints always gets to short-circuit the
    loop right away.

-----------------------------------------------------------------------

Summary of changes:
 dwflpp.cxx  |   28 ++++++----------------------
 dwflpp.h    |    2 --
 tapsets.cxx |    6 +++---
 3 files changed, 9 insertions(+), 27 deletions(-)


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