# Darwin debugging for the Linux developer These technical notes are meant to explain to a Linux developer what are the equivalents to debug certain things over Darwin. ### Key differences from Linux Linux tool | macOS equivalent | Purpose -----------|-----------------------------------------|------------------------ `strace` | `dtruss` (1), [`strace-macos`](https://github.com/Mic92/strace-macos) | System call tracing `perf` | `sample`, `spindump`, `Instruments` (2) | Performance profiling `ss` | `netstat -nv` | Socket statistics `iostat` | `iostat -Id` | Disk I/O statistics `lsof` | `lsof` | Open file listings `/proc` | `vmmap`, `heap`, `lsof` | Process/memory information `blktrace` | `fs_usage -wf filesys` | Trace real-time IO activity (1): `dtruss` is unavailable on systems with System Integrity Protection enabled (SIP). Lix CI machines have SIP enabled. (2): `Instruments` is a graphical application that requires a remote desktop and cannot be used over SSH. ### Getting flamegraphs out of `sample` Combine with . ### Inspecting memory allocations `heap` can give a list of allocations sorted by sizes when it can recognize the type in-memory (doesn't always work for everything). ### `iostat` tips `iostat -Id` on macOS will return as the first row the cumulative data *SINCE* the first boot. `xfrs` := IO operations per second. ### Listing file descriptors `/proc` doesn't exist on macOS, therefore, `lsof` is the only thing that can list file descriptors and let you understand the relationships. ### Tracing network activity `fs_usage -wf network` can trace real-time network activity on file descriptors. ### Checking Internet quality `networkQuality -v` will dump an Apple-infrastructure Internet connection check for bandwidth and latency.