How We Used eBPF + Rust to Observe AI Systems Without Instrumenting a Single Line of Code

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • MyrinNew
    Senior Member
    • Feb 2024
    • 5168

    #1

    How We Used eBPF + Rust to Observe AI Systems Without Instrumenting a Single Line of Code


    Production observability for AI systems is broken.

    We fixed it by moving below the application layer.


    Why Traditional Observability Completely Fails for AI Workloads

    Modern AI systems don’t behave like classical web services.


    They are:
    • Highly asynchronous
    • GPU-bound
    • Framework-heavy (PyTorch, TensorRT, CUDA, ONNX)
    • Opaque once deployed


    Yet we still observe them using:
    • HTTP middleware
    • Language-level tracing
    • Application instrumentation
      This creates three fatal problems:


    ❌ Problem 1: Instrumentation Bias


    You only see what the developer remembered to instrument.


    ❌ Problem 2: Runtime Overhead


    AI inference latency is measured in microseconds. Traditional tracing adds milliseconds.


    ❌ Problem 3: Blind Spots


    Once execution crosses into:
    • CUDA
    • Kernel drivers
    • Syscalls
    • GPU scheduling


    👉 Your observability stops existing.


    The Radical Idea: Observe AI Systems From the Kernel

    Instead of instrumenting applications, we observe reality.


    That means:
    • Syscalls
    • Memory allocations
    • Network traffic
    • GPU interactions
    • Thread scheduling
      And we do it using eBPF.


    What Is eBPF (In One Precise Paragraph)

    eBPF (extended Berkeley Packet Filter) allows you to run sandboxed programs inside the Linux kernel, safely and dynamically, without kernel modules or reboots.


    Key properties:
    • Runs at kernel-level
    • Zero userland instrumentation
    • Verified for safety
    • Extremely low overhead (~nanoseconds)


    This makes it perfect for AI observability.


    Why Rust Is the Only Sane Choice Here

    Writing kernel-adjacent code is dangerous.


    Rust gives us:
    • Memory safety
    • Zero-cost abstractions
    • Strong typing across kernel/user boundary
    • No GC pauses

      We use:
    • aya for eBPF
    • no_std eBPF programs
    • Async Rust in userland


    Architecture Overview





    ┌─────────────┐
    │ AI Service │
    │ (Python) │
    └──────┬──────┘


    ┌───────────────────┐
    │ Linux Kernel │
    │ │
    │ eBPF Programs │◄───── Tracepoints
    │ │ Kprobes
    └──────┬────────────┘
    │ Ring Buffer

    ┌───────────────────┐
    │ Rust Userland │
    │ Collector │
    └──────┬────────────┘

    ┌───────────────────┐
    │ AI Observability │
    │ Pipeline │
    └───────────────────┘







    Step 1: Tracing AI Inference Without Touching Python

    We attach eBPF programs to:
    • sys_enter_mmap
    • sys_enter_ioctl
    • sched_switch
    • tcp_sendmsg


    This gives us:
    • Model load times
    • GPU driver calls
    • Thread contention
    • Network inference latency
      Example: eBPF Program (Rust)




    #[kprobe(name = "trace_ioctl")]
    pub fn trace_ioctl(ctx: ProbeContext) -> u32 {
    let pid = bpf_get_current_pid_tgid() >> 32;
    let cmd = ctx.arg:1).unwrap_or(0);

    EVENT_QUEUE.output(&ctx, &IoctlEvent { pid, cmd }, 0);
    0
    }







    No Python changes.

    No framework hooks.

    No SDK.


    Step 2: Detecting GPU Bottlenecks Indirectly (But Reliably)

    We can’t run eBPF on the GPU.


    But we can observe:
    • CUDA driver syscalls
    • Memory pressure patterns
    • Context switches per inference
      We discovered a powerful signal:


    Inference latency spikes correlate strongly with kernel-level context switching density


    This is something no APM tool shows you.


    Step 3: AI-Specific Metrics You’ve Never Seen Before

    Using kernel data, we derive new metrics:


    🔬 Kernel-Derived AI Metrics


    Inference syscall density(Model inefficiency)

    GPU driver contention(Multi-model interference)

    Memory map churn(Model reload bugs)

    Thread migration rate(NUMA misconfiguration)


    These metrics predict:
    • Latency regressions
    • OOM crashes
    • GPU starvation
      before they happen


    Step 4: Feeding the Data Into AI Observability

    We stream events via:
    • Ring buffers
    • Async Rust
    • OpenTelemetry exporters


    Then we:
    • Correlate kernel events with inference IDs
    • Build flamegraphs below the runtime
    • Detect anomalies using statistical baselines


    Performance Impact (The Real Question)

    Method(Overhead)

    Traditional tracing(5–15%)

    Python profiling(10–30%)

    eBPF (ours)(< 1%)


    Measured under sustained GPU inference load.


    Why This Changes Everything

    This approach:
    • Works for any language
    • Works for closed-source models
    • Works in production
    • Survives framework upgrades


    It’s observability that cannot lie.


    When You Should Not Use This

    Be honest in your dev.to post (this increases trust):


    ❌ If you don’t control the host

    ❌ If you’re on non-Linux systems

    ❌ If you need simple dashboards only


    The Future: Autonomous AI Debugging at Kernel Level

    Next steps we’re exploring:
    • Automatic root-cause detection
    • eBPF-powered AI guardrails
    • Self-healing inference pipelines
    • WASM-based policy engines


    Final Thought


    You can’t observe modern AI systems from the application layer anymore.

    Reality lives in the kernel.




    More...
Working...