For now they are, and that might hold true in the future as well.
There are some projects to bring BPF features needed (generally called eBPF) to FreeBSD, such as https://github.com/YutaroHayakawa/generic-ebpf - but there's no accepted mainline implementation as of yet.
Comments
This is huge. The Linux community should be glad that Netflix hired Brendan Gregg to work on Linux performance.
Is this because they are also using Linux or do they plan to use it on FreeBSD?
They use both. Control plane runs on Linux, CDN on FreeBSD.
Those aren’t mutually exclusive options.
For now they are, and that might hold true in the future as well.
There are some projects to bring BPF features needed (generally called eBPF) to FreeBSD, such as https://github.com/YutaroHayakawa/generic-ebpf - but there's no accepted mainline implementation as of yet.