Re: [PATCH v2] tracing/function-graph-tracer: prevent from hrtimer interrupt infinite loop

From: Frédéric Weisbecker
Date: Mon Dec 22 2008 - 05:46:59 EST


2008/12/21 Frédéric Weisbecker <fweisbec@xxxxxxxxx>:
> 2008/12/21 Ingo Molnar <mingo@xxxxxxx>:
>>
>> * Ingo Molnar <mingo@xxxxxxx> wrote:
>>
>>> btw., a graph-tracer buglet i noticed:
>>
>> another thing. I turned off all the options that come ahead of the 'meat'
>> of the trace data:
>>
>> # cat /debug/tracing/trace_options
>> print-parent nosym-offset nosym-addr noverbose noraw nohex nobin noblock
>> nostacktrace nosched-tree ftrace_printk noftrace_preempt nobranch annotate
>> nouserstacktrace nosym-userobj printk-msg-only nofuncgraph-overrun
>> nofuncgraph-cpu nofuncgraph-overhead nofuncgraph-proc
>>
>> but i still got the 'duration' field printed:
>>
>> # tracer: function_graph
>> #
>> # DURATION FUNCTION CALLS
>> # | | | | |
>>
>> 0.865 us | }
>> | alloc_page_vma() {
>> 0.295 us | get_vma_policy();
>> 0.268 us | policy_zonelist();
>> | __alloc_pages_internal() {
>> 0.257 us | __might_sleep();
>> | get_page_from_freelist() {
>>
>>
>> i'd have expected to only see the flow of execution as it happens.
>>
>> Ingo
>>
>
>
> Strange. I will test that.
>

Did I say it was strange? No it isn't, there is no option to turn off
the duration :-)
I will add one.
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