perf backtraces miss libepoxy function and function that calls it

[vvavrychuk]

I am debugging virglrenderer which uses libepoxy on Adreno GPU. I use following perf command for that:

perf record -e kgsl:kgsl_mem_alloc -g -p PID

as result I obtain following data traces like

ffffff800877a910 gpumem_alloc_entry ([kernel.kallsyms])
ffffff800877a910 gpumem_alloc_entry ([kernel.kallsyms])
ffffff800877a9a4 kgsl_ioctl_gpuobj_alloc ([kernel.kallsyms])
ffffff8008787b30 kgsl_ioctl_helper ([kernel.kallsyms])
ffffff8008787ba8 kgsl_ioctl ([kernel.kallsyms])
ffffff8008294f14 do_vfs_ioctl ([kernel.kallsyms])
ffffff800829537c sys_ioctl ([kernel.kallsyms])
ffffff8008083918 __sys_trace_return ([kernel.kallsyms])
           d87dc ioctl (/lib/libc-2.28.so)
           10cf0 vrend_decode_clear (/lib/libvirglrenderer.so.1.4.2)
           147a8 vrend_decode_block (/lib/libvirglrenderer.so.1.4.2)
            f79c virgl_renderer_submit_cmd (/lib/libvirglrenderer.so.1.4.2)

The problem is that in that backtrace I miss actual OpenGL call (glClear) and one function which calls it (vrend_clear). Even though I have compiled everything with -O0. This situation is similiar for all virglrenderer/libepoxy backtraces. Correct backtrace could be

           d87dc ioctl (/lib/libc-2.28.so)
               ????? glClear
               ????? vrend_clear (/lib/libvirglrenderer.so.1.4.2)
           10cf0 vrend_decode_clear (/lib/libvirglrenderer.so.1.4.2)

Could you please suggest anything.

Thank you!