Function sample_process_with_window

src/runtime_telemetry.rs:170–210

(cpu_sample_window: Duration)

}

fn sample_process_with_window(cpu_sample_window: Duration) -> ProcessSnapshot {
    let pid = Pid::from_u32(std::process::id());

    // Refresh only *our own* process. The previous implementation passed
    // `.with_processes(..)` to `System::new_with_specifics`, which enumerates
    // and samples every process on the host — by far the heaviest part of the
    // reported Windows `tracedecay_runtime` crash (STATUS_STACK_OVERFLOW on a
    // host with a large process table). The primary fix for that crash is the
    // explicit-stack entrypoint in `main.rs` (`ASYNC_STACK_BYTES`: Windows
    // gives the main thread only 1 MiB); scoping the refresh to our PID
    // additionally bounds this handler's work and memory regardless of host
    // process count. `sample_process_fits_in_a_small_stack` guards the stack
    // footprint of this path.
    let refresh = ProcessRefreshKind::new().with_cpu().with_memory();
    let mut sys = System::new_with_specifics(
        RefreshKind::new()
            .with_memory(sysinfo::MemoryRefreshKind::new().with_ram())
            .with_cpu(sysinfo::CpuRefreshKind::new()),
    );
    // Two reads bracketing a sleep are required: sysinfo reports
    // `cpu_usage()` as the delta between successive refreshes.
    sys.refresh_processes_specifics(sysinfo::ProcessesToUpdate::Some(&[pid]), true, refresh);
    std::thread::sleep(cpu_sample_window);
    sys.refresh_processes_specifics(sysinfo::ProcessesToUpdate::Some(&[pid]), true, refresh);

    let proc = sys.process(pid);
    let rss_bytes = proc.map_or(0, sysinfo::Process::memory);
    let virtual_bytes = proc.map_or(0, sysinfo::Process::virtual_memory);
    let cpu_percent = proc.map_or(0.0, sysinfo::Process::cpu_usage);
    let uptime_secs = proc.map_or(0, sysinfo::Process::run_time);

    ProcessSnapshot {
        pid: std::process::id(),
        rss_bytes,
        virtual_bytes,
        cpu_percent,
        uptime_secs,
        system_cpu_count: sys.cpus().len(),
        system_total_memory_bytes: sys.total_memory(),
    }
}

// ---------------------------------------------------------------------------
// Database sampling