Re: Recompile QEMU with frame-pointers

[Salvatore Mazzarino]

Unfortunately it did not work.

Here the flags

../configure \
    --enable-werror \
    --extra-cflags="-fno-omit-frame-pointer" \
    --target-list="x86_64-softmmu" \
    --disable-gcrypt \
    --enable-nettle \
    --enable-docs \
    --enable-fdt=system \
    --enable-slirp=system \
    --enable-capstone=system

 And the profile I’m using is this https://github.com/iovisor/bcc/blob/master/tools/profile.py

But the result I get is still 

profile -F 99 -d -f -K -p $(pgrep qemu) 20
qemu-system-x86;[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown] 1
qemu-system-x86;[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown] 1
qemu-system-x86;[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown] 1
qemu-system-x86;[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown] 1

On 28 January 2021 at 19:13:35, Peter Maydell (peter.maydell@linaro.org) wrote:

On Thu, 28 Jan 2021 at 18:08, Salvatore Mazzarino
<apocalipse89@gmail.com> wrote:
>
> I have compiled QEMU with the following flags
>
> ../configure \
> --enable-werror \
> --enable-trace-backend=simple \
> --enable-debug \
> --target-list="x86_64-softmmu" \
> --disable-gcrypt \
> --enable-nettle \
> --enable-docs \
> --enable-fdt=system \
> --enable-slirp=system \
> --enable-capstone=system
>
>
> what I still get when I run perf command bcc/tools/profile is
>
>
> qemu-system-x86;[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown];[unknown] 1

Nope, because I have no idea what that profiling tool is looking at.
You can check the executables that get built to see if they have
the debug info you need in them. If the framepointer is the issue
you can use --extra-cflags as I suggested.

PS: run the executable in the build tree, not after install, because
I have a feeling 'make install' might run 'strip' on it.

thanks
-- PMM