Network

From examples/kitchen-sink in the source checkout, prepare one Linux controller for both scripts. These scripts require Linux or WSL:

julia setup-linux.jl
julia --project=.controller/linux oxygen/network.jl
julia --project=.controller/linux oxygen/network-isolated.jl

For the public API below, start Julia with julia --project=.controller/linux. It checks capability before capture:

using PerfChecker
spec = NetworkIsolationSpec(provider=:linux_netns, interface="lo")
capabilities = network_isolation_capabilities(spec; probe=true)
if capabilities["supported"]
    result = measure_isolated_network_command(
        [Base.julia_cmd().exec..., "--project=.controller/linux", "oxygen/network.jl"];
        spec, timeout_seconds=180)
    display(isolated_network_result_dict(result))
else
    display(capabilities)
end

The actual isolated receipt records supported=true, executed=true, exit 0 and 120 verified requests. The linux-netns-nftables provider observed 69,465,109 bytes sent and 69,466,045 bytes received, with zero discarded packets. Capture scope is the isolated process tree over its lifecycle, 13.662857426 s, not pure HTTP handler latency. Ordinary interface counters include unrelated traffic unless isolation establishes attribution.

Recorded network samples

Open the same interactive export

Download the serialized plot

Attribution and platform options

• :network records application-reported counters. They describe payload only when that is the workload's counter contract.

• :network_interface observes a shared host interface; unrelated traffic prevents attribution unless the host is hermetic.

• :network_isolated uses a dedicated namespace; measure_isolated_network_command covers the full isolated command tree.

Loopback observes the transfer in both transmit and receive counters: do not sum them as payload. The default unprivileged namespace is loopback-only. external_connectivity=true uses slirp4netns for outbound IPv4/DNS and adds user-mode-stack overhead. Windows can use NetworkIsolationSpec(provider=:wsl2_netns, distribution="Ubuntu"); the published capture above is Linux evidence, not a WSL recording. Native Windows process-tree attribution through ETW/WFP/Pktmon is not implemented. Host-interface counters use Get-NetAdapterStatistics.