test

Signed-off-by: Anastasios Papagiannis <[email protected]>

bpf/include/api.h

@@ -227,7 +227,7 @@ static __u64 BPF_FUNC(get_attach_cookie, void *ctx);
 
 static long BPF_FUNC(loop, __u32 nr_loops, void *callback_fn, void *callback_ctx, __u64 flags);
 
-static long BPF_FUNC(ringbuf_output, void *data, uint64_t size, uint64_t flags);
+static long BPF_FUNC(ringbuf_output, void *ringbuf, void *data, uint64_t size, uint64_t flags);
 static void BPF_FUNC(ringbuf_reserve, void *ringbuf, uint64_t size, uint64_t flags);
 static void BPF_FUNC(ringbuf_submit, void *data, uint64_t flags);
 static void BPF_FUNC(ringbuf_discard, void *data, uint64_t flags);

bpf/lib/bpf_event.h

@@ -11,9 +11,8 @@ struct event {
 };
 
 struct {
-	__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
-	__type(key, int);
-	__type(value, struct event);
+	__uint(type, BPF_MAP_TYPE_RINGBUF);
+	__uint(max_entries, 8LU * 1024LU * 1024LU); // 8MB
 } tcpmon_map SEC(".maps");
 
 #endif // __BPF_EVENT_H

bpf/lib/process.h

@@ -582,7 +582,7 @@ static inline __attribute__((always_inline)) void perf_event_output_metric(void
 	__u32 zero = 0;
 	long err;
 
-	err = perf_event_output(ctx, map, flags, data, size);
+	err = ringbuf_output(map, data, size, 0);
 	if (err < 0) {
 		valp = map_lookup_elem(&tg_stats_map, &zero);
 		if (valp)

bpf/test/bpf_lseek.c

@@ -49,8 +49,7 @@ test_lseek(struct sys_enter_lseek_args *ctx)
 		msg.common.ktime = ktime_get_ns();
 		msg.common.size = size;
 		msg.arg0 = get_smp_processor_id();
-		perf_event_output(ctx, &tcpmon_map, BPF_F_CURRENT_CPU, &msg,
-				  size);
+		ringbuf_output(&tcpmon_map, &msg, size, 0);
 	}
 
 	return 0;

pkg/bpf/perf_linux.go

@@ -8,24 +8,15 @@ import (
 	"io"
 	"os"
 	"path/filepath"
-	"runtime"
 	"strings"
-
-	"golang.org/x/sys/unix"
 )
 
 const (
 	PossibleCPUSysfsPath = "/sys/devices/system/cpu/possible"
 )
 
 type PerfEventConfig struct {
-	NumCpus      int
-	NumPages     int
-	MapName      string
-	Type         int
-	Config       int
-	SampleType   int
-	WakeupEvents int
+	MapName string
 }
 
 // GetNumPossibleCPUs returns a total number of possible CPUS, i.e. CPUs that
@@ -74,30 +65,7 @@ func getNumPossibleCPUsFromReader(r io.Reader) int {
 // DefaultPerfEventConfig returns the default perf event configuration. It
 // relies on the map root to be set.
 func DefaultPerfEventConfig() *PerfEventConfig {
-	numCpus := GetNumPossibleCPUs()
-	if numCpus == 0 {
-		numCpus = runtime.NumCPU()
-	}
 	return &PerfEventConfig{
-		MapName:      filepath.Join(MapPrefixPath(), eventsMapName),
-		Type:         PERF_TYPE_SOFTWARE,
-		Config:       PERF_COUNT_SW_BPF_OUTPUT,
-		SampleType:   PERF_SAMPLE_RAW,
-		WakeupEvents: 1,
-		NumCpus:      numCpus,
-		NumPages:     128,
-	}
-}
-
-func UpdateElementFromPointers(fd int, structPtr, sizeOfStruct uintptr) error {
-	ret, _, err := unix.Syscall(
-		unix.SYS_BPF,
-		BPF_MAP_UPDATE_ELEM,
-		structPtr,
-		sizeOfStruct,
-	)
-	if ret != 0 || err != 0 {
-		return fmt.Errorf("Unable to update element for map with file descriptor %d: %s", fd, err)
+		MapName: filepath.Join(MapPrefixPath(), eventsMapName),
 	}
-	return nil
 }

pkg/observer/observer.go

@@ -7,7 +7,6 @@ import (
 	"bytes"
 	"context"
 	"fmt"
-	"math"
 	"os"
 	"runtime"
 	"strings"
@@ -16,7 +15,7 @@ import (
 	"time"
 
 	"github.com/cilium/ebpf"
-	"github.com/cilium/ebpf/perf"
+	"github.com/cilium/ebpf/ringbuf"
 	"github.com/cilium/tetragon/pkg/api/ops"
 	"github.com/cilium/tetragon/pkg/api/readyapi"
 	"github.com/cilium/tetragon/pkg/bpf"
@@ -33,10 +32,6 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
-const (
-	perCPUBufferBytes = 65535
-)
-
 var (
 	eventHandler = make(map[uint8]func(r *bytes.Reader) ([]Event, error))
 
@@ -144,23 +139,6 @@ func (k *Observer) receiveEvent(data []byte) {
 	}
 }
 
-// Gets final size for single perf ring buffer rounded from
-// passed size argument (kindly borrowed from ebpf/cilium)
-func perfBufferSize(perCPUBuffer int) int {
-	pageSize := os.Getpagesize()
-
-	// Smallest whole number of pages
-	nPages := (perCPUBuffer + pageSize - 1) / pageSize
-
-	// Round up to nearest power of two number of pages
-	nPages = int(math.Pow(2, math.Ceil(math.Log2(float64(nPages)))))
-
-	// Add one for metadata
-	nPages++
-
-	return nPages * pageSize
-}
-
 func sizeWithSuffix(size int) string {
 	suffix := [4]string{"", "K", "M", "G"}
 
@@ -173,26 +151,6 @@ func sizeWithSuffix(size int) string {
 	return fmt.Sprintf("%d%s", size, suffix[i])
 }
 
-func (k *Observer) getRBSize(cpus int) int {
-	var size int
-
-	if option.Config.RBSize == 0 && option.Config.RBSizeTotal == 0 {
-		size = perCPUBufferBytes
-	} else if option.Config.RBSize != 0 {
-		size = option.Config.RBSize
-	} else {
-		size = option.Config.RBSizeTotal / int(cpus)
-	}
-
-	cpuSize := perfBufferSize(size)
-	totalSize := cpuSize * cpus
-
-	k.log.WithField("percpu", sizeWithSuffix(cpuSize)).
-		WithField("total", sizeWithSuffix(totalSize)).
-		Info("Perf ring buffer size (bytes)")
-	return size
-}
-
 func (k *Observer) getRBQueueSize() int {
 	size := option.Config.RBQueueSize
 	if size == 0 {
@@ -211,11 +169,9 @@ func (k *Observer) RunEvents(stopCtx context.Context, ready func()) error {
 	}
 	defer perfMap.Close()
 
-	rbSize := k.getRBSize(int(perfMap.MaxEntries()))
-	perfReader, err := perf.NewReader(perfMap, rbSize)
-
+	rd, err := ringbuf.NewReader(perfMap)
 	if err != nil {
-		return fmt.Errorf("creating perf array reader failed: %w", err)
+		return fmt.Errorf("opening ringbuf reader: %w", err)
 	}
 
 	// Inform caller that we're about to start processing events.
@@ -224,7 +180,7 @@ func (k *Observer) RunEvents(stopCtx context.Context, ready func()) error {
 
 	// We spawn go routine to read and process perf events,
 	// connected with main app through eventsQueue channel.
-	eventsQueue := make(chan *perf.Record, k.getRBQueueSize())
+	eventsQueue := make(chan *ringbuf.Record, k.getRBQueueSize())
 
 	// Listeners are ready and about to start reading from perf reader, tell
 	// user everything is ready.
@@ -237,7 +193,7 @@ func (k *Observer) RunEvents(stopCtx context.Context, ready func()) error {
 	go func() {
 		defer wg.Done()
 		for stopCtx.Err() == nil {
-			record, err := perfReader.Read()
+			record, err := rd.Read()
 			if err != nil {
 				// NOTE(JM and Djalal): count and log errors while excluding the stopping context
 				if stopCtx.Err() == nil {
@@ -256,11 +212,6 @@ func (k *Observer) RunEvents(stopCtx context.Context, ready func()) error {
 					k.recvCntr++
 					ringbufmetrics.PerfEventReceived.Inc()
 				}
-
-				if record.LostSamples > 0 {
-					atomic.AddUint64(&k.lostCntr, uint64(record.LostSamples))
-					ringbufmetrics.PerfEventLost.Add(float64(record.LostSamples))
-				}
 			}
 		}
 	}()
@@ -290,7 +241,7 @@ func (k *Observer) RunEvents(stopCtx context.Context, ready func()) error {
 
 	// Wait for context to be cancelled and then stop.
 	<-stopCtx.Done()
-	return perfReader.Close()
+	return rd.Close()
 }
 
 // Observer represents the link between the BPF perf ring and the listeners. It

pkg/testutils/perfring/perfring.go

@@ -15,7 +15,7 @@ import (
 	"testing"
 
 	"github.com/cilium/ebpf"
-	"github.com/cilium/ebpf/perf"
+	"github.com/cilium/ebpf/ringbuf"
 	"github.com/cilium/tetragon/pkg/bpf"
 	testapi "github.com/cilium/tetragon/pkg/grpc/test"
 	"github.com/cilium/tetragon/pkg/logger"
@@ -69,7 +69,7 @@ func ProcessEvents(t *testing.T, ctx context.Context, eventFn EventFn, wgStarted
 	}
 	defer perfMap.Close()
 
-	perfReader, err := perf.NewReader(perfMap, 65535)
+	rd, err := ringbuf.NewReader(perfMap)
 	if err != nil {
 		t.Fatalf("creating perf array reader failed: %v", err)
 	}
@@ -96,7 +96,7 @@ func ProcessEvents(t *testing.T, ctx context.Context, eventFn EventFn, wgStarted
 				break
 			}
 
-			record, err := perfReader.Read()
+			record, err := rd.Read()
 			if err != nil {
 				if ctx.Err() == nil {
 					errChan <- fmt.Errorf("error reading perfring data: %v", err)
@@ -127,11 +127,11 @@ func ProcessEvents(t *testing.T, ctx context.Context, eventFn EventFn, wgStarted
 		case err := <-errChan:
 			t.Fatal(err)
 		case <-complChan:
-			perfReader.Close()
+			rd.Close()
 			return
 		case <-ctx.Done():
 			// Wait for context cancel.
-			perfReader.Close()
+			rd.Close()
 			return
 		}
 	}