Update selftest

Signed-off-by: grantseltzer <grantseltzer@gmail.com>

libbpfgo.go

@@ -640,7 +640,6 @@ func (b *BPFMap) GetValue(key unsafe.Pointer) ([]byte, error) {
 
 func (b *BPFMap) GetValue2(key unsafe.Pointer, value *[]byte) error {
 	valuePtr := unsafe.Pointer(&(*value)[0])
-	fmt.Println("fd: ", b.fd)
 	errC := C.bpf_map_lookup_elem(b.fd, key, valuePtr)
 	if errC != 0 {
 		return fmt.Errorf("failed to lookup value %v in map %s: %w", key, b.name, syscall.Errno(-errC))

selftest/percpu/main.bpf.c

@@ -11,7 +11,7 @@
 struct {
 	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
 	__uint(max_entries, 1);
-	__type(key, __u64);
+	__type(key, __u32);
 	__type(value, __u64);
 } percpu_hash SEC(".maps");
 

selftest/percpu/main.go

@@ -3,6 +3,7 @@ package main
 import "C"
 
 import (
+	"encoding/binary"
 	"fmt"
 	"os"
 	"runtime"
@@ -28,20 +29,12 @@ func main() {
 		os.Exit(-1)
 	}
 
-	bpfModule.ListProgramNames()
-
 	prog, err := bpfModule.GetProgram("mmap_fentry")
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(-1)
 	}
 
-	lostEventCounterMap, err := bpfModule.GetMap("percpu_hash")
-	if err != nil {
-		fmt.Fprintln(os.Stderr, err)
-		os.Exit(-1)
-	}
-
 	link, err := prog.AttachGeneric()
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
@@ -58,30 +51,24 @@ func main() {
 		}
 	}()
 
-	// all values regardless of size are rounded up to 8 for struct
-	// padding in PERCPU maps
-	valueSize := 8 * runtime.NumCPU()
-	fmt.Println(valueSize)
-	err = lostEventCounterMap.SetValueSize(uint32(valueSize))
+	lostEventCounterMap, err := bpfModule.GetMap("percpu_hash")
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(-1)
 	}
 
 	time.Sleep(time.Second * 2)
 	key := 0
-	val, err := lostEventCounterMap.GetValue(unsafe.Pointer(&key))
+	values := make([]byte, 8*runtime.NumCPU())
+	err = lostEventCounterMap.GetValue2(unsafe.Pointer(&key), &values)
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(-1)
 	}
 
 	last := 0
-	fmt.Println("len", len(val))
 	for i := 0; i < runtime.NumCPU(); i++ {
-		fmt.Println((val[last : last+8]))
+		fmt.Printf("CPU %d: %d\n", i, binary.LittleEndian.Uint32(values[last:last+8]))
 		last += 8
 	}
-
-	time.Sleep(time.Minute)
 }