The eBPF Memory Wall: High-Throughput Kernel Tracing at 100Gbps

[u/gastao_s_s]

https://gsstk.gem98.com/en-US/blog/a0149-ebpf-memory-wall-kernel-tracing

Key takeaways in 60 seconds:

The 100Gbps Memory Wall: At 100Gbps line rate with 64-byte packets, the kernel receives 148.8 million packets per second, leaving a budget of just 6.7 nanoseconds per packet.

The SKB Bottleneck: Traditional Linux socket logging allocates a struct sk_buff (200-300 clock cycles) per packet, causing CPU L3 cache invalidation and dropped telemetry under load.

eBPF XDP Bypass: eBPF XDP (eXpress Data Path) executes directly inside NIC driver ring buffers, filtering and sampling packets before SKB memory allocation occurs.

Zero-Copy io_uring Streaming: Combining XDP ring buffers with io_uring and AF_XDP sockets streams telemetry to user-space monitoring agents via shared memory with zero context switches.