benchmarks/

Benchmarks

Two kinds live in this repository:

• Door benchmarks (mtglib/door_bench_test.go, and mtglib/internal/middleproxy/stream_bench_test.go for the ad-tag leg): whole streams through ServeConn on real loopback sockets, per door. These are the yardstick a performance change is judged by.
• Micro-benchmarks in this directory and in mtglib/internal/relay/, inherited from mtg-multi; ANALYSIS.md discusses them.

Results are committed under results/, one file per run, so a change can be compared with what came before it rather than with memory.

What the door benchmarks report

Every bulk benchmark counts every byte and fails on a short count. The fake Telegram never decrypts and the load generator keeps its buffers from setup, so the CPU and allocations measured are the proxy's.

Doors: ee-record (FakeTLS with the doppelganger pacing as shipped), ee-burst (the same with shaping = "burst"), ee-unpaced (the same with Ganger.Unpace), dd, plain.

Take latency numbers on Linux: Go's clock on Windows advances in steps of about half a millisecond.

Running them on the bench box

The bench box is a 2 vCPU Linux VM that also runs another project's database. On it:

• work only in /root/mtg-bench, and remove it at the end of a session;
• install nothing — binaries are cross-compiled here and copied over;
• loopback only;
• keep one run to about ten minutes of load, which is why runs are six one-second samples rather than ten two-second ones;
• raise the descriptor limit first (ulimit -n 16384): the idle benchmark holds 1,000 streams, four sockets each.

The test's own sockets are reset rather than closed at the end of a stream, because thousands of connections a second otherwise fill the kernel's TIME_WAIT table (16,384 there) and stall a dial for ~15 s. If a handshake benchmark ever reports a mean far above its neighbours, check ss -Htan state time-wait | wc -l before suspecting the proxy.

# here
GOOS=linux GOARCH=amd64 CGO_ENABLED=0 go test -c -o mtglib.test ./mtglib
GOOS=linux GOARCH=amd64 CGO_ENABLED=0 go test -c -o middleproxy.test ./mtglib/internal/middleproxy
scp mtglib.test middleproxy.test <box>:/root/mtg-bench/

# on the box, once per GOMAXPROCS value (2, then 1)
cd /root/mtg-bench && chmod +x *.test && ulimit -n 16384
GOMAXPROCS=2 ./mtglib.test -test.run '^$' -test.bench . -test.benchmem -test.count 6 -test.benchtime 1s > mtglib-p2.txt
GOMAXPROCS=2 ./middleproxy.test -test.run '^$' -test.bench . -test.benchmem -test.count 6 -test.benchtime 1s > middleproxy-p2.txt

# back here: compare with the committed baseline
GOBIN=<scratch> go install golang.org/x/perf/cmd/benchstat@latest
benchstat results/2026-10-02-tierA-baseline.txt <new file>

-test.run '^$' matters: a test binary run away from its source tree cannot find golden files, so the tests themselves would fail there.

Limits

Two vCPU, not the 4–8 of the target server: per-core cost and one-to-two core scaling are measured, scaling beyond that is not. Loopback, not a network card: these measure the proxy's own cost — CPU per byte, added latency, memory per connection.