Messages in this thread | | | Date | Wed, 6 Jan 2010 14:08:06 +0100 | From | Jiri Olsa <> | Subject | Re: tracing: confusing output of function_graph when notrace function calls traceable function |
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On Wed, Jan 06, 2010 at 06:44:02PM +0800, Lai Jiangshan wrote: > cat <debugfs_dir>/tracing/trace > you can get these at the end of the outputs: > > 1) | nameidata_to_filp() { > 1) | __dentry_open() { > 1) | file_move() { > 1) 0.834 us | _raw_spin_lock(); > 1) 0.926 us | _raw_spin_unlock(); > 1) 4.768 us | } > > !!!! file_move() is really called by __dentry_open() > > 1) | kmem_cache_alloc_notrace() { > 1) 5.879 us | memset(); > 1) + 12.390 us | } > 1) 1.025 us | mutex_lock(); > 1) | kmem_cache_alloc_notrace() { > 1) 0.929 us | memset(); > 1) 3.329 us | } > 1) 1.195 us | memcpy(); > 1) 1.026 us | __mutex_init(); > > !!!! the above are actually called by __tracing_open() which called by __dentry_open() > (But at the first I was confused, I wondered why __dentry_open() calls them.) > > 1) | kmem_cache_alloc_notrace() { > 1) 0.978 us | memset(); > 1) 2.745 us | } > 1) | __alloc_percpu() { > 1) | pcpu_alloc() { > 1) 1.053 us | mutex_lock(); > 1) 1.282 us | _raw_spin_lock_irqsave(); > 1) | pcpu_size_to_slot() { > 1) 0.819 us | __pcpu_size_to_slot(); > 1) 5.455 us | } > 1) 1.135 us | pcpu_need_to_extend(); > 1) | pcpu_alloc_area() { > 1) | pcpu_chunk_slot() { > 1) | pcpu_size_to_slot() { > 1) 0.813 us | __pcpu_size_to_slot(); > 1) 2.535 us | } > 1) 8.349 us | } > 1) 1.160 us | memmove(); > 1) | pcpu_chunk_relocate() { > 1) | pcpu_chunk_slot() { > 1) | pcpu_size_to_slot() { > 1) 0.803 us | __pcpu_size_to_slot(); > 1) 2.478 us | } > 1) 4.129 us | } > 1) 8.583 us | } > 1) + 29.665 us | } > 1) 1.038 us | _raw_spin_unlock_irqrestore(); > 1) 1.178 us | pcpu_next_pop(); > 1) 1.087 us | pcpu_chunk_addr(); > 1) 0.975 us | memset(); > 1) 0.821 us | pcpu_chunk_addr(); > 1) 0.943 us | memset(); > 1) 0.896 us | mutex_unlock(); > 1) + 75.625 us | } > 1) + 77.453 us | } > > !!!! the above are actually called by graph_trace_open() which called by __tracing_open() > > == real graph ==: > > father_fun() > child_fun() > notrace_child_fun() > grandchild_fun1() > grandchild_fun2() > > ===function_graph shows===> > > father_fun() > child_fun() > grandchild_fun1() > grandchild_fun2() > > When the notrace function calls traceable function, function_graph will > get wrong depth of functions, and show wrong graph. > > Is there any method to fix it? I dont think so..
AFAIK the depth computation is based on the traced functions, and there's no other 'depth related' input apart from them.
jirka > > Lai > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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