chore(pkg/bpf): Replace libbpfgo with cilium/ebpf

cilium/ebpf is a pure Go eBPF package and is used in a number of popular
cloud-native projects. The benefits to Kepler are:

1. Bytecode is built using bpf2go and the C and Go structs are kept in
   sync automatically
2. There is no requirement for Cgo anymore and therefore no requirement
   to have libbpf or libelf installed to compile and/or to be
   dynamically linked at runtime
3. Simplified packaging as the correct bytecode is contained within the
   kepler binary

Overall I'm happy with this change, but there is only one thing that
bugs me.

We have to check in the bytecode object files (e.g kepler.bpfel.o) or
the Go tooling (go lint/go vet) complains about the missing files.
I couldn't reliably get `go generate ./...` to work to compile these
files in CI. This is something which should be relatively easy to fix
in the Makefile/CI environment before we cut a release.

Signed-off-by: Dave Tucker <dave@dtucker.co.uk>

.github/workflows/c.yml

@@ -14,14 +14,4 @@ jobs:
       - uses: jidicula/clang-format-action@v4.13.0
         with:
           clang-format-version: "17"
-          check-path: bpfassets/libbpf/src
-
-  build:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4.1.1
-      - name: Install libbpf
-        run: |
-          sudo apt-get update && sudo apt-get install -y libelf-dev libbpf-dev
-      - name: Build
-        run: make -C bpfassets/libbpf
+          check-path: pkg/bpf/src

.github/workflows/unit_test.yml

@@ -22,6 +22,7 @@ jobs:
       - uses: actions/setup-go@v5
         with:
           go-version-file: go.mod
+      - run: sudo apt-get install clang llvm
       - name: Get ginkgo
         run: make ginkgo-set
         env:
@@ -32,21 +33,8 @@ jobs:
           sudo apt-get install -y cpuid clang
           cd doc/ && sudo ./dev/prepare_dev_env.sh && cd -
           git config --global --add safe.directory /kepler
-      - name: install libbpf
-        uses: sustainable-computing-io/kepler-action@v0.0.7
-        with:
-          ebpfprovider: libbpf
       - name: Run
         run: |
-          sudo apt remove libbpf-dev
-          mkdir temp-libbpf
-          cd temp-libbpf
-          git clone https://github.com/libbpf/libbpf
-          cd libbpf/src
-          sudo make install_headers
-          sudo make install_uapi_headers
-          sudo prefix=/usr  BUILD_STATIC_ONLY=y make install
-          cd ../../../
           make VERBOSE=1 test
           go tool cover -func=coverage.out -o=coverage.out
 

.gitignore

@@ -41,8 +41,8 @@ local-dev-cluster
 /tmp
 .env
 
-# object files
-*.o
-
 # test coverage
 coverage.out
+
+# old libbpf-based binaries
+bpfassets/

.pre-commit-config.yaml

@@ -20,4 +20,4 @@ repos:
     rev: v1.59.1
     hooks:
       - id: golangci-lint
-exclude: ^vendor/.*|^_output/.*|^bpfassets/libbpf/include/.*
+exclude: ^vendor/.*|^_output/.*|^pkg/bpf/include/.*

Makefile

@@ -51,14 +51,9 @@ endif
 GOOS := $(shell go env GOOS)
 GOARCH := $(shell go env GOARCH)
 
-LIBBPF_HEADERS := /usr/include/bpf
 GOENV = GO111MODULE="" \
 				GOOS=$(GOOS) \
-				GOARCH=$(GOARCH) \
-				CGO_ENABLED=1 \
-				CC=clang \
-				CGO_CFLAGS="-I $(LIBBPF_HEADERS) -I/usr/include/" \
-				CGO_LDFLAGS="-lelf -lz -lbpf"
+				GOARCH=$(GOARCH)
 
 LDFLAGS := $(LDFLAGS) \
 		-X main.Version=$(VERSION) \
@@ -67,7 +62,6 @@ LDFLAGS := $(LDFLAGS) \
 		-X main.OS=$(GOOS) \
 		-X main.Arch=$(GOARCH)
 
-
 DOCKERFILE := $(SRC_ROOT)/build/Dockerfile
 IMAGE_BUILD_TAG := $(GIT_VERSION)-linux-$(GOARCH)
 GO_BUILD_TAGS := $(GENERAL_TAGS)$(GOOS)$(GPU_TAGS)
@@ -169,10 +163,11 @@ clean-cross-build:
 build: clean_build_local _build_local copy_build_local ##  Build binary and copy to $(OUTPUT_DIR)/bin
 .PHONY: build
 
-_build_ebpf_local:
-	@make -C bpfassets/libbpf
+.PHONY: generate
+generate: ## Generate BPF code locally.
+	+@$(GOENV) go generate ./pkg/bpf
 
-_build_local: _build_ebpf_local ##  Build Kepler binary locally.
+_build_local: generate ##  Build Kepler binary locally.
 	@echo TAGS=$(GO_BUILD_TAGS)
 	@mkdir -p "$(CROSS_BUILD_BINDIR)/$(GOOS)_$(GOARCH)"
 	+@$(GOENV) go build \
@@ -277,7 +272,7 @@ SUDO_TEST_PKGS := $(shell go list ./... | grep pkg/bpf)
 test: unit-test bpf-test bench ## Run all tests.
 
 .PHONY: unit-test
-unit-test: ginkgo-set tidy-vendor ## Run unit tests.
+unit-test: generate ginkgo-set tidy-vendor ## Run unit tests.
 	@echo TAGS=$(GO_TEST_TAGS)
 	$(if $(VERBOSE),@echo GOENV=$(GOENV))
 	@$(GOENV) go test -tags $(GO_TEST_TAGS) \
@@ -295,7 +290,7 @@ bench: ## Run benchmarks.
 		-bench=. --count=1 $(TEST_PKGS)
 
 .PHONY: bpf-test
-bpf-test: _build_ebpf_local ## Run BPF tests.
+bpf-test: generate ## Run BPF tests.
 	for pkg in $(SUDO_TEST_PKGS); do \
 		$(GOENV) go test -c $$pkg -tags $(GO_TEST_TAGS) -cover \
 		-covermode=atomic -coverprofile=coverage.bpf.out \
@@ -322,7 +317,7 @@ format:
 
 c-format:
 	@echo "Checking c format"
-	@git ls-files -- '*.c' '*.h' ':!:vendor' ':!:bpfassets/libbpf/include/' | xargs clang-format --dry-run --Werror
+	@git ls-files -- '*.c' '*.h' ':!:vendor' ':!:pkg/bpf/include/' | xargs clang-format --dry-run --Werror
 
 golint:
 	@mkdir -p $(base_dir)/.cache/golangci-lint

build/Dockerfile

@@ -56,9 +56,7 @@ COPY --from=builder /libbpf-source/linux-5.14.0-424.el9/tools/bpf/bpftool/bpftoo
 COPY --from=builder /libbpf-source/linux-5.14.0-424.el9/tools/bpf/bpftool/bpftool /usr/bin/bpftool
 
 RUN mkdir -p /var/lib/kepler/data
-RUN mkdir -p /var/lib/kepler/bpfassets
 COPY --from=builder /workspace/data/cpus.yaml /var/lib/kepler/data/cpus.yaml
-COPY --from=builder /workspace/bpfassets/libbpf/bpf.o /var/lib/kepler/bpfassets
 
 # copy model weight
 COPY --from=builder /workspace/data/model_weight/acpi_AbsPowerModel.json /var/lib/kepler/data/acpi_AbsPowerModel.json

go.mod

@@ -1,12 +1,14 @@
 module github.com/sustainable-computing-io/kepler
 
-go 1.21
+go 1.21.0
+
+toolchain go1.21.9
 
 require (
 	github.com/HabanaAI/gohlml v1.15.0
 	github.com/NVIDIA/go-dcgm v0.0.0-20240118201113-3385e277e49f
 	github.com/NVIDIA/go-nvml v0.12.0-1
-	github.com/aquasecurity/libbpfgo v0.6.0-libbpf-1.3
+	github.com/cilium/ebpf v0.15.0
 	github.com/jaypipes/ghw v0.12.0
 	github.com/joho/godotenv v1.5.1
 	github.com/jszwec/csvutil v1.10.0
@@ -66,6 +68,7 @@ require (
 	github.com/prometheus/procfs v0.12.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
 	github.com/stretchr/testify v1.9.0 // indirect
+	golang.org/x/exp v0.0.0-20240119083558-1b970713d09a // indirect
 	golang.org/x/net v0.25.0 // indirect
 	golang.org/x/oauth2 v0.19.0 // indirect
 	golang.org/x/term v0.20.0 // indirect

go.sum

@@ -8,8 +8,6 @@ github.com/NVIDIA/go-nvml v0.12.0-1 h1:6mdjtlFo+17dWL7VFPfuRMtf0061TF4DKls9pkSw6
 github.com/NVIDIA/go-nvml v0.12.0-1/go.mod h1:hy7HYeQy335x6nEss0Ne3PYqleRa6Ct+VKD9RQ4nyFs=
 github.com/StackExchange/wmi v1.2.1 h1:VIkavFPXSjcnS+O8yTq7NI32k0R5Aj+v39y29VYDOSA=
 github.com/StackExchange/wmi v1.2.1/go.mod h1:rcmrprowKIVzvc+NUiLncP2uuArMWLCbu9SBzvHz7e8=
-github.com/aquasecurity/libbpfgo v0.6.0-libbpf-1.3 h1:mhDe1mAZR80LjnsCnteS+R2/EeBFi9qFjKslsIJwVSo=
-github.com/aquasecurity/libbpfgo v0.6.0-libbpf-1.3/go.mod h1:0rEApF1YBHGuZ4C8OYI9q5oDBVpgqtRqYATePl9mCDk=
 github.com/armon/go-socks5 v0.0.0-20160902184237-e75332964ef5 h1:0CwZNZbxp69SHPdPJAN/hZIm0C4OItdklCFmMRWYpio=
 github.com/armon/go-socks5 v0.0.0-20160902184237-e75332964ef5/go.mod h1:wHh0iHkYZB8zMSxRWpUBQtwG5a7fFgvEO+odwuTv2gs=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
@@ -18,6 +16,8 @@ github.com/bits-and-blooms/bitset v1.13.0 h1:bAQ9OPNFYbGHV6Nez0tmNI0RiEu7/hxlYJR
 github.com/bits-and-blooms/bitset v1.13.0/go.mod h1:7hO7Gc7Pp1vODcmWvKMRA9BNmbv6a/7QIWpPxHddWR8=
 github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
 github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
+github.com/cilium/ebpf v0.15.0 h1:7NxJhNiBT3NG8pZJ3c+yfrVdHY8ScgKD27sScgjLMMk=
+github.com/cilium/ebpf v0.15.0/go.mod h1:DHp1WyrLeiBh19Cf/tfiSMhqheEiK8fXFZ4No0P1Hso=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
@@ -41,6 +41,8 @@ github.com/go-openapi/jsonreference v0.20.4 h1:bKlDxQxQJgwpUSgOENiMPzCTBVuc7vTdX
 github.com/go-openapi/jsonreference v0.20.4/go.mod h1:5pZJyJP2MnYCpoeoMAql78cCHauHj0V9Lhc506VOpw4=
 github.com/go-openapi/swag v0.22.9 h1:XX2DssF+mQKM2DHsbgZK74y/zj4mo9I99+89xUmuZCE=
 github.com/go-openapi/swag v0.22.9/go.mod h1:3/OXnFfnMAwBD099SwYRk7GD3xOrr1iL7d/XNLXVVwE=
+github.com/go-quicktest/qt v1.101.0 h1:O1K29Txy5P2OK0dGo59b7b0LR6wKfIhttaAhHUyn7eI=
+github.com/go-quicktest/qt v1.101.0/go.mod h1:14Bz/f7NwaXPtdYEgzsx46kqSxVwTbzVZsDC26tQJow=
 github.com/go-task/slim-sprig/v3 v3.0.0 h1:sUs3vkvUymDpBKi3qH1YSqBQk9+9D/8M2mN1vB6EwHI=
 github.com/go-task/slim-sprig/v3 v3.0.0/go.mod h1:W848ghGpv3Qj3dhTPRyJypKRiqCdHZiAzKg9hl15HA8=
 github.com/gogo/protobuf v1.3.2 h1:Ov1cvc58UF3b5XjBnZv7+opcTcQFZebYjWzi34vdm4Q=
@@ -145,6 +147,8 @@ go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/exp v0.0.0-20240119083558-1b970713d09a h1:Q8/wZp0KX97QFTc2ywcOE0YRjZPVIx+MXInMzdvQqcA=
+golang.org/x/exp v0.0.0-20240119083558-1b970713d09a/go.mod h1:idGWGoKP1toJGkd5/ig9ZLuPcZBC3ewk7SzmH0uou08=
 golang.org/x/mod v0.2.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/mod v0.3.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=

hack/libbpf-headers.sh

@@ -16,4 +16,4 @@ headers=(
 
 # Fetch libbpf release and extract the desired headers
 curl -sL "https://github.com/libbpf/libbpf/archive/refs/tags/v${LIBBPF_VERSION}.tar.gz" | \
-    tar -C ./bpfassets/libbpf/include/bpf -xz --xform='s#.*/##' "${headers[@]}"
+    tar -C ./pkg/bpf/include/bpf -xz --xform='s#.*/##' "${headers[@]}"

packaging/rpm/kepler.spec

@@ -54,13 +54,10 @@ install -d %{buildroot}%{_bindir}
 install -d %{buildroot}%{_sysconfdir}/kepler/
 
 install -d %{buildroot}/var/lib/kepler/data
-install -d %{buildroot}/var/lib/kepler/bpfassets
 install -d %{buildroot}/etc/kepler/kepler.config
 
 install -p -m755 ./_output/kepler  %{buildroot}%{_bindir}/kepler
 install -p -m644 ./packaging/rpm/kepler.service %{buildroot}%{_unitdir}/kepler.service
-install -p -m644 ./bpfassets/libbpf/bpf.o/kepler.bpfel.o %{buildroot}/var/lib/kepler/bpfassets/kepler.bpfel.o
-install -p -m644 ./bpfassets/libbpf/bpf.o/kepler.bpfeb.o %{buildroot}/var/lib/kepler/bpfassets/kepler.bpfeb.o
 install -p -m644 ./_output/ENABLE_PROCESS_METRICS %{buildroot}/etc/kepler/kepler.config/ENABLE_PROCESS_METRICS
 install -p -m644 ./data/cpus.yaml %{buildroot}/var/lib/kepler/data/cpus.yaml
 install -p -m644 ./data/model_weight/acpi_AbsPowerModel.json %{buildroot}/var/lib/kepler/data/acpi_AbsPowerModel.json
@@ -76,8 +73,6 @@ install -p -m644 ./data/model_weight/intel_rapl_DynPowerModel.json %{buildroot}/
 %license LICENSE
 %{_bindir}/kepler
 %{_unitdir}/kepler.service
-/var/lib/kepler/bpfassets/kepler.bpfel.o
-/var/lib/kepler/bpfassets/kepler.bpfeb.o
 /var/lib/kepler/data/cpus.yaml
 /var/lib/kepler/data/acpi_AbsPowerModel.json
 /var/lib/kepler/data/acpi_DynPowerModel.json

pkg/bpf/bpf_suite_test.go

@@ -13,18 +13,19 @@ import (
 
 func TestBpf(t *testing.T) {
 	RegisterFailHandler(Fail)
-	RunSpecs(t, "Attacher Suite")
+	RunSpecs(t, "Bpf Suite")
 }
 
-func checkDataCollected(processesData []ProcessBPFMetrics) {
-	// len > 0
+func checkDataCollected(processesData []ProcessMetrics) {
 	Expect(len(processesData)).To(BeNumerically(">", 0))
-	Expect(processesData[0].PID).To(BeNumerically(">=", uint64(0)))
-	Expect(processesData[0].Command).NotTo(BeEmpty())
-	Expect(processesData[0].CPUCycles).To(BeNumerically(">=", uint64(0)))
-	Expect(processesData[0].CPUInstr).To(BeNumerically(">=", uint64(0)))
-	Expect(processesData[0].CacheMisses).To(BeNumerically(">=", uint64(0)))
-	Expect(processesData[0].CGroupID).To(BeNumerically(">", uint64(0)))
+	for _, p := range processesData {
+		Expect(p.Pid).To(BeNumerically(">=", 0))
+		Expect(p.Comm).NotTo(BeEmpty())
+		Expect(p.CpuCycles).To(BeNumerically(">=", uint64(0)))
+		Expect(p.CpuInstr).To(BeNumerically(">=", uint64(0)))
+		Expect(p.CacheMiss).To(BeNumerically(">=", uint64(0)))
+		Expect(p.CgroupId).To(BeNumerically(">=", uint64(0)))
+	}
 }
 
 var _ = Describe("BPF Exporter test", func() {