Re: [PATCH 1/2] tracing/function-graph-tracer: signal interrupts entry/exit points on outpout

[Frédéric Weisbecker]

2008/12/8 Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>:
> On Mon, 2008-12-08 at 01:54 +0100, Frederic Weisbecker wrote:
>> Impact: provide interrupt detection on output
>>
>> Suggested by Ingo.
>> If a hardirq is raised, we want it to be signaled on output, so this patch
>> adds two arrows on the output to find entry and exit points of a hardirq.
>>
>> Unfortunately, there are many interrupt entrypoints and these can be differents
>> from one arch to another.
>>
>> The approach here is one of the easiest, but doesn't shine by its scalability:
>> we have an array of the interrupt entrypoints names that we compare with the
>> symbol of the current traced function, if it matches, we draw the arrow.
>>
>> Ie:
>>
>>  1)               |                                unlock_buffer() {
>>  1)               |                                  wake_up_bit() {
>>  1)               |                                    bit_waitqueue() {
>>  1)   0.872 us    |                                      __phys_addr();
>>  1)   2.722 us    |                                    }
>>  1)               |                                    __wake_up_bit() {
>>  1)              ==>                                   __wake_up_bit() {
>>  1)               |                                      do_IRQ() {
>
> Would be much nicer, the current proposal is lost when grepping and adds
> a weird visual break in the output.


Ok, I will apply it like this in the V2.
Thanks!
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