I have been using the flamegraph profiler, rs-flamegraph, quite successfully over the past few days. When I run it from bash it works fine. No sudo or anything.
~/.cargo/bin/flamegraph -o "$f flamegraph.svg" ./binary
When I invoke the binary from Rust using process::Command it fails saying that it cannot sample collapsed stack.
let svgfilename = format!("{} flamegraph.svg", path);
let execution = std::process::Command::new("/home/arkadiusz/.cargo/bin/flamegraph")
.arg("-o").arg(&svgfilename)
.arg("./binary").arg("solve").arg("real-data").arg("/dev/null")
.output().unwrap();
Full error:
WARNING: Kernel address maps (/proc/{kallsyms,modules}) are restricted,
check /proc/sys/kernel/kptr_restrict and /proc/sys/kernel/perf_event_paranoid.
Samples in kernel functions may not be resolved if a suitable vmlinux
file is not found in the buildid cache or in the vmlinux path.
Samples in kernel modules won't be resolved at all.
If some relocation was applied (e.g. kexec) symbols may be misresolved
even with a suitable vmlinux or kallsyms file.
Couldn't record kernel reference relocation symbol
Symbol resolution may be skewed if relocation was used (e.g. kexec).
Check /proc/kallsyms permission or run as root.
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0,000 MB (null) ]
thread 'main' panicked at 'unable to generate a flamegraph from the collapsed stack data: Io(Custom { kind: InvalidData, error: "No stack counts found" })', /home/arkadiusz/.cargo/registry/src/github.com-1ecc6299db9ec823/flamegraph-0.4.0/src/lib.rs:315:6
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace