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bac429f037
Impact: new profiling feature This patch adds a function profiler. In debugfs/tracing/ two new files are created. function_profile_enabled - to enable or disable profiling trace_stat/functions - the profiled functions. For example: echo 1 > /debugfs/tracing/function_profile_enabled ./hackbench 50 echo 0 > /debugfs/tracing/function_profile_enabled yields: cat /debugfs/tracing/trace_stat/functions Function Hit -------- --- _spin_lock 10106442 _spin_unlock 10097492 kfree 6013704 _spin_unlock_irqrestore 4423941 _spin_lock_irqsave 4406825 __phys_addr 4181686 __slab_free 4038222 dput 4030130 path_put 4023387 unroll_tree_refs 4019532 [...] The most hit functions are listed first. Functions that are not hit are not listed. This feature depends on and uses dynamic function tracing. When the function profiling is disabled, no overhead occurs. But it still takes up around 300KB to hold the data, thus it is not recomended to keep it enabled for systems low on memory. When a '1' is echoed into the function_profile_enabled file, the counters for is function is reset back to zero. Thus you can see what functions are hit most by different programs. Signed-off-by: Steven Rostedt <srostedt@redhat.com> |
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| linux | ||
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