instrumened so cannot generate prof.fdata

I have libc.so.6(with relation and debug info arm64 ) and i want to instrument it
`llvm-bolt libc.so.6 --instrument --instrumentation-sleep-time=30 --o libc.so.proc.instr.30s.so.6`
however i found that it can work on arm64 device but it can not generata /tmp/prof.fdata(i check this dir is writeable)

i think it maybe many processed use libc.so.6 so it cannot generata prof file

is there any way to fix this

Start by reproducing the llvm-bolt command on the ARM64 device and inspect whether the instrumented libc process reaches the profiling output step. Check the writable /tmp location and the behavior when multiple processes use the instrumented library. Done means the command reliably generates /tmp/prof.fdata, with the failure cause documented or fixed.

Written by the indexing model from the issue text.