Re: [Qemu-devel] About the trace framework

[Wang Dong]

On 07/11/2017 05:39 PM, Xie Changlong wrote:
> 在 7/11/2017 9:33 AM, Wang Dong 写道:
> > On 07/10/2017 01:24 PM, Xie Changlong wrote:
> > > 在 7/9/2017 5:57 PM, Wang Dong 写道:
> > > > Hi,
> > > >
> > > > I am new to QEMU. But I got some problem so that  I want to figure 
> > > > it out.
> > > >
> > > > So I try to debug qemu to see what happened.
> > > >
> > > > And I found trace framework. I think this will help me understand 
> > > > the point.
> > > >
> > > > So I compiled qemu with option:
> > > >
> > > > ## *--enable-trace-backends=simple*
> > > >
> > > > And did as the docs/tracing.txt tell. But when I execute the 
> > > > example command in it, nothing just happens.
> > > >
> > > > *./scripts/simpletrace.py trace-events-all trace-xxxxxx(my trace 
> > > > file produced by qemu)
> > > > I am not sure what happened. Just ask this.
> > > > Any clue will be appreciated. Thanks in advance.
> > > > *
> > >
> > > Did you set *trace-event*? I've encountered this issue in the past :)
> > > (qemu) help trace-event
> > > trace-event name on|off -- changes status of a specific trace event
> > > (qemu) info trace-events
> > yes, I set it. I just did as the docs told. If this does not work or 
> > misses something, it should be corrected I think.
> >
> > Have you also tried out the examples in docs? how did you do that? I 
>
> Yes, just follow the docs. No something special.
>
> > think I misses some. Could you tell more about
> > it? Thanks.
>
> You should confirm the *trace-event*s you set are really triggered by 
> qemu. Use gdb breakpoint to verify it is a good choice.
>
> >
OK, I will try that. Thanks for your advice.

--
Best regards. Wang Dong