Re: [PATCH] tracing/function-graph-tracer: adjustments of thetrace informations

From: Peter Zijlstra
Date: Sat Nov 29 2008 - 05:59:43 EST


On Sat, 2008-11-29 at 04:40 +0100, FrÃdÃric Weisbecker wrote:
> 2008/11/28 Ingo Molnar <mingo@xxxxxxx>:

> I tried to figure out a way to signal a hardirq in a trace, I like
> this arrow but It
> breaks the indentation.
> I would suggest:
>
> 0) | skb_dequeue() {
> 0) 0.365 us | _spin_lock_irqsave();
> 0) 0.422 us | _spin_unlock_irqrestore();
> 0) 1.912 us | }
> 0) | memcpy_toiovec() {
> 0) | copy_to_user() {
> =====>
> 0) | smp_apic_timer_interrupt() {
> 0) 0.450 us | native_apic_mem_write();
> 0) | irq_enter() {
> 0) 0.410 us | idle_cpu();
> 0) 1.167 us | }
> 0) | hrtimer_interrupt() {
>
> Your idea solves a part of one of the features I wanted to add: why
> not using a single character column to print
> the current context: workqueue, syscall, kernel thread, tasklet, hardirq .....

That was my initial suggestion too, like the latency tracer has.

Then again, most of that would be obvious from the comm/pid column, that
will show preemption and all those things.

But showing Hard,Soft irq disabled and perhaps the preempt count would
be handy.

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