Messages in this thread |  | | | Date | Wed, 06 Jan 2010 18:44:02 +0800 | | From | Lai Jiangshan <> | | Subject | tracing: confusing output of function_graph when notrace function calls traceable function |
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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?
Lai
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