fix off-by-10 error

johnstcn · johnstcn · commit d1bb3224c23e · 2023-06-13T17:33:39.000+01:00
diff --git a/cli/clistat/cgroup.go b/cli/clistat/cgroup.go
@@ -5,7 +5,6 @@ import (
 	"bytes"
 	"strconv"
 	"strings"
-	"time"
 
 	"github.com/spf13/afero"
 	"golang.org/x/xerrors"
@@ -105,7 +104,12 @@ func (s *Statter) cGroupV2CPUUsed() (used float64, err error) {
 	if err != nil {
 		return 0, xerrors.Errorf("get cgroupv2 cpu used: %w", err)
 	}
-	return (time.Duration(usageUs) * time.Microsecond).Seconds(), nil
+	periodUs, err := readInt64SepIdx(s.fs, cgroupV2CPUMax, " ", 1)
+	if err != nil {
+		return 0, xerrors.Errorf("get cpu period: %w", err)
+	}
+
+	return float64(usageUs) / float64(periodUs), nil
 }
 
 func (s *Statter) cGroupV2CPUTotal() (total float64, err error) {
@@ -153,7 +157,14 @@ func (s *Statter) cGroupV1CPUUsed() (float64, error) {
 		}
 	}
 
-	return time.Duration(usageNs).Seconds(), nil
+	// usage is in ns, convert to us
+	usageNs /= 1000
+	periodUs, err := readInt64(s.fs, cgroupV1CFSPeriodUs)
+	if err != nil {
+		return 0, xerrors.Errorf("get cpu period: %w", err)
+	}
+
+	return float64(usageNs) / float64(periodUs), nil
 }
 
 // ContainerMemory returns the memory usage of the container cgroup.
diff --git a/cli/clistat/stat_internal_test.go b/cli/clistat/stat_internal_test.go
@@ -108,7 +108,7 @@ func TestStatter(t *testing.T) {
 			fs := initFS(t, fsContainerCgroupV1)
 			fakeWait := func(time.Duration) {
 				// Fake 1 second in ns of usage
-				mungeFS(t, fs, cgroupV1CPUAcctUsage, "1000000000")
+				mungeFS(t, fs, cgroupV1CPUAcctUsage, "100000000")
 			}
 			s, err := New(WithFS(fs), withWait(fakeWait))
 			require.NoError(t, err)
@@ -126,7 +126,7 @@ func TestStatter(t *testing.T) {
 			fs := initFS(t, fsContainerCgroupV1NoLimit)
 			fakeWait := func(time.Duration) {
 				// Fake 1 second in ns of usage
-				mungeFS(t, fs, cgroupV1CPUAcctUsage, "1000000000")
+				mungeFS(t, fs, cgroupV1CPUAcctUsage, "100000000")
 			}
 			s, err := New(WithFS(fs), withNproc(2), withWait(fakeWait))
 			require.NoError(t, err)
@@ -160,8 +160,7 @@ func TestStatter(t *testing.T) {
 			t.Parallel()
 			fs := initFS(t, fsContainerCgroupV2)
 			fakeWait := func(time.Duration) {
-				// Fake 1 second in ns of usage
-				mungeFS(t, fs, cgroupV2CPUStat, "usage_usec 1000000")
+				mungeFS(t, fs, cgroupV2CPUStat, "usage_usec 100000")
 			}
 			s, err := New(WithFS(fs), withWait(fakeWait))
 			require.NoError(t, err)
@@ -178,8 +177,7 @@ func TestStatter(t *testing.T) {
 			t.Parallel()
 			fs := initFS(t, fsContainerCgroupV2NoLimit)
 			fakeWait := func(time.Duration) {
-				// Fake 1 second in ns of usage
-				mungeFS(t, fs, cgroupV2CPUStat, "usage_usec 1000000")
+				mungeFS(t, fs, cgroupV2CPUStat, "usage_usec 100000")
 			}
 			s, err := New(WithFS(fs), withNproc(2), withWait(fakeWait))
 			require.NoError(t, err)
