libct/int: add exec benchmark

[kolyshkin]

Related to: #3181

This is a benchmark which checks how fast we can execute /bin/true
inside a container.

Results from my machine are below. As you can see, in default setup
about 70% of exec time is spent for CVE-2019-5736 (copying runc binary),
and using either RUNC_DMZ=true or memfd-bind helps a lot.

This can also be used for profiling (using -test.cpuprofile option).

Default setup

[kir@kir-tp1 integration]$ sudo ./integration.test -test.run xxx -test.v -test.benchtime 5s -test.count 5 -test.bench . .
goos: linux
goarch: amd64
pkg: github.com/opencontainers/runc/libcontainer/integration
cpu: 12th Gen Intel(R) Core(TM) i7-12800H
BenchmarkExecTrue
BenchmarkExecTrue-20                 327          24475677 ns/op
BenchmarkExecTrue-20                 244          25242718 ns/op
BenchmarkExecTrue-20                 232          26187174 ns/op
BenchmarkExecTrue-20                 237          26780030 ns/op
BenchmarkExecTrue-20                 318          18487219 ns/op
PASS

With DMZ enabled

[kir@kir-tp1 integration]$ sudo -E RUNC_DMZ=true ./integration.test -test.run xxx -test.v -test.benchtime 5s -test.count 5 -test.bench . .
goos: linux
goarch: amd64
pkg: github.com/opencontainers/runc/libcontainer/integration
cpu: 12th Gen Intel(R) Core(TM) i7-12800H
BenchmarkExecTrue
BenchmarkExecTrue-20                 694           8263744 ns/op
BenchmarkExecTrue-20                 778           8483228 ns/op
BenchmarkExecTrue-20                 784           8456018 ns/op
BenchmarkExecTrue-20                 732           8160239 ns/op
BenchmarkExecTrue-20                 769           8236972 ns/op
PASS

With memfd-bind

[kir@kir-tp1 integration]$ sudo systemctl start  memfd-bind@$(systemd-escape -p $PWD/integration.test)
[kir@kir-tp1 integration]$ sudo ./integration.test -test.run xxx -test.v -test.benchtime 5s -test.count 5 -test.bench . .
goos: linux
goarch: amd64
pkg: github.com/opencontainers/runc/libcontainer/integration
cpu: 12th Gen Intel(R) Core(TM) i7-12800H
BenchmarkExecTrue
BenchmarkExecTrue-20                 800           7538839 ns/op
BenchmarkExecTrue-20                 717           7424755 ns/op
BenchmarkExecTrue-20                 848           7747787 ns/op
BenchmarkExecTrue-20                 800           7668740 ns/op
BenchmarkExecTrue-20                 751           7304373 ns/op
PASS

Signed-off-by: Kir Kolyshkin kolyshkin@gmail.com

[cyphar]

LGTM

[kolyshkin]

@AkihiroSuda @rata PTAL. It's just a benchmark so not risky to merge but it's helpful to have.

[rata]

This mostly LGTM, just left a question of a possible race.

This might be a silly question, but how are you running this? Where is the integration.test binary coming from? I run this with go test -bench, but I couldn't find how to build that binary you are using.

[kolyshkin]

This might be a silly question, but how are you running this?

The easiest way is

[kir@kir-tp1 runc]$ go test -v -run 234 -bench . -benchmem -exec sudo ./libcontainer/integration/
goos: linux
goarch: amd64
pkg: github.com/opencontainers/runc/libcontainer/integration
cpu: 12th Gen Intel(R) Core(TM) i7-12800H
BenchmarkExecTrue
BenchmarkExecTrue-20    	      57	  23171808 ns/op	   27448 B/op	     242 allocs/op
PASS
ok  	github.com/opencontainers/runc/libcontainer/integration	1.601s

Where is the integration.test binary coming from?

[kir@kir-tp1 runc]$ go test -c ./libcontainer/integration/

I was using the compiled version in the description since sudo makes it complicated to pass environment variables needed (you'd need something like go test -v -run 234 -bench . -benchmem -exec 'sudo -E RUNC_DMZ=true' ./libcontainer/integration/ and it becomes messy).

[rata]

@kolyshkin thanks! LGTM