Messages in this thread | | | Date | Fri, 20 Feb 2009 09:39:02 +0100 | From | Ingo Molnar <> | Subject | Re: [rfd] function-graph augmentation |
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* Peter Zijlstra <peterz@infradead.org> wrote:
> Hi, > > I was thinking how best to augment the function graph tracer > with various information. It seemed useful to add > argument/return tracer entries which, when found after a > function entry, or function exit entry would be rendered in > the trace. > > So supposing something like; > > 3) | handle_mm_fault() { > 3) | count_vm_event() { > 3) 0.243 us | test_ti_thread_flag(); > 3) 0.754 us | } > 3) 0.249 us | pud_alloc(); > 3) 0.251 us | pmd_alloc(); > 3) | __do_fault() { > 3) | filemap_fault() { > 3) | find_lock_page() { > 3) | find_get_page() { > 3) 0.248 us | test_ti_thread_flag(); > 3) 0.844 us | } > 3) 1.341 us | } > 3) 1.837 us | } > 3) 0.275 us | _spin_lock(); > 3) 0.257 us | page_add_file_rmap(); > 3) 0.233 us | native_set_pte_at(); > 3) | _spin_unlock() { > 3) 0.248 us | test_ti_thread_flag(); > 3) 0.742 us | } > 3) | unlock_page() { > 3) 0.243 us | page_waitqueue(); > 3) 0.237 us | __wake_up_bit(); > 3) 1.209 us | } > 3) 6.274 us | } > 3) 8.806 us | } > > Say we found: > > trace_graph_entry -- handle_mm_fault() > trace_func_arg -- address:0xffffffff > trace_func_arg -- write_access:1 > > We'd render: > > 3) | handle_mm_fault(.address=0xffffffff, .write_access=1) { > > trace_graph_return -- handle_mm_fault() > trace_func_ret -- 2 > > We'd render: > > 3) 8.806 us | } = 2 > > Then we can register with tracepoints inside functions to add > these generic trace_func_arg/_ret entries to augment the graph > (and or function) tracer. > > Does that make sense?
Yeah, it looks really nice that way.
Ingo
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