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From: | Naman patel |
Subject: | Re: [Qemu-devel] Call Trace for QEMU functions |
Date: | Fri, 31 Jul 2015 14:59:10 +0530 |
Peter Maydell <address@hidden> writes:
> 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.
With the perf JIT patch you can get a better handle on the profile. I'll
see if I can re-spin them tomorrow for the latest tree.
>
> thanks
> -- PMM
--
Alex Bennée
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