Re: [Qemu-devel] Call Trace for QEMU functions

[Peter Maydell]

On 30 July 2015 at 13:20, Naman patel <address@hidden> wrote:
> Hi,
>
>      I have compiled QEMU (2.0) for x86_64 on Fedora 22 with tracing enabled
> and the tracing option I chose was dtrace. I have this script called
> callTrace.stp in which I try and get the Call Trace of the function
> helper_invlpg and later tlb_flush.  But I am not able to get the function
> name of the caller function and the call trace depth is only limited to 2.

The helper_invlpg function is called directly from code generated
by QEMU's built-in JIT, not from any other C function.

If you use a newer version of QEMU than 2.0 then I think we have
fixed some of the stack frame information up so that you can
get a backtrace that looks like:
 * helper function
 * [generated code]
 * QEMU execution loop code that handles executing guest code
 * other QEMU functions

This is not likely to be very useful for profiling why or when
we're calling a particular helper function, though.

thanks
-- PMM