flamegraph comes out flat when using on Docker (debian)

[jasonwilliams]

Steps to reproduce

• Clone https://github.com/jasonwilliams/boa
• Start the docker container with the image provided (i do this via vscode)
• Install perf - sudo apt-get install linux-perf
• Run cargo flamegraph --dev --bin boa_cli
• Open up the flamegraph.svg

[jonas-schievink]

Does perf work?

[jasonwilliams]

Yeah perf is there on the path and working by the looks of it

[jonas-schievink]

Have you checked if the output of perf report looks similarly broken?

[jasonwilliams]

perf report seems fine from what i can see

[jasonwilliams]

removing --dev i did get

undefined[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.006 MB perf.data ]
thread 'main' panicked at 'assertion failed: self.event_filter.is_some()', /usr/local/cargo/registry/src/github.com-1ecc6299db9ec823/inferno-0.9.4/src/collapse/perf.rs:165:9
stack backtrace:
   0: backtrace::backtrace::libunwind::trace
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.40/src/backtrace/libunwind.rs:88
   1: backtrace::backtrace::trace_unsynchronized
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.40/src/backtrace/mod.rs:66
   2: std::sys_common::backtrace::_print_fmt
             at src/libstd/sys_common/backtrace.rs:84
   3: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
             at src/libstd/sys_common/backtrace.rs:61
   4: core::fmt::write
             at src/libcore/fmt/mod.rs:1025
   5: std::io::Write::write_fmt
             at src/libstd/io/mod.rs:1426
   6: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:65
   7: std::sys_common::backtrace::print
             at src/libstd/sys_common/backtrace.rs:50
   8: std::panicking::default_hook::{{closure}}
             at src/libstd/panicking.rs:193
   9: std::panicking::default_hook
             at src/libstd/panicking.rs:210
  10: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:471
  11: std::panicking::begin_panic
  12: <T as inferno::collapse::Collapse>::collapse
  13: flamegraph::generate_flamegraph_for_workload
  14: cargo_flamegraph::main
  15: std::rt::lang_start::{{closure}}
  16: std::rt::lang_start_internal::{{closure}}
             at src/libstd/rt.rs:52
  17: std::panicking::try::do_call
             at src/libstd/panicking.rs:292
  18: __rust_maybe_catch_panic
             at src/libpanic_unwind/lib.rs:78
  19: std::panicking::try
             at src/libstd/panicking.rs:270
  20: std::panic::catch_unwind
             at src/libstd/panic.rs:394
  21: std::rt::lang_start_internal
             at src/libstd/rt.rs:51
  22: main
  23: __libc_start_main
  24: _start
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

[jasonwilliams]

It also does that when i add --freq 2 (or any number)

[jonas-schievink]

Hmm, interesting. This might be an issue with inferno then.