prometheus/cadvisor
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Merge pull request #145 from vmarmol/allow-lower

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Saturate samples to 0 if they are negative.
This commit is contained in:
monnand 2014-08-04 12:43:58 -04:00
commit d10247cae4
2 changed files with 18 additions and 13 deletions
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20
info/container.go
View File

@ -368,6 +368,14 @@ type ContainerStatsPercentiles struct {
CpuUsagePercentiles []Percentile `json:"cpu_usage_percentiles,omitempty"`
}
// Saturate CPU usage to 0.
func calculateCpuUsage(prev, cur uint64) uint64 {
if prev > cur {
return 0
}
return cur - prev
}
// Each sample needs two stats because the cpu usage in ContainerStats is
// cumulative.
// prev should be an earlier observation than current.
@ -384,10 +392,6 @@ func NewSample(prev, current *ContainerStats) (*ContainerStatsSample, error) {
if !current.Timestamp.After(prev.Timestamp) {
return nil, fmt.Errorf("wrong stats order")
}
// This data is invalid.
if current.Cpu.Usage.Total < prev.Cpu.Usage.Total {
return nil, fmt.Errorf("current CPU usage is less than prev CPU usage (cumulative).")
}
var percpu []uint64
@ -400,15 +404,13 @@ func NewSample(prev, current *ContainerStats) (*ContainerStatsSample, error) {
if i < len(prev.Cpu.Usage.PerCpu) {
prevUsage = prev.Cpu.Usage.PerCpu[i]
}
if currUsage < prevUsage {
return nil, fmt.Errorf("current per-core CPU usage is less than prev per-core CPU usage (cumulative).")
}
percpu[i] = currUsage - prevUsage
percpu[i] = calculateCpuUsage(prevUsage, currUsage)
}
}
sample := new(ContainerStatsSample)
// Calculate the diff to get the CPU usage within the time interval.
sample.Cpu.Usage = current.Cpu.Usage.Total - prev.Cpu.Usage.Total
sample.Cpu.Usage = calculateCpuUsage(prev.Cpu.Usage.Total, current.Cpu.Usage.Total)
sample.Cpu.PerCpuUsage = percpu
// Memory usage is current memory usage
sample.Memory.Usage = current.Memory.Usage

11
info/container_test.go
View File

@ -213,11 +213,11 @@ func TestAddSampleWrongOrder(t *testing.T) {
sample, err := NewSample(current, prev)
if err == nil {
t.Errorf("generated an unexpected sample: %+v", sample)
t.Errorf("generated an unexpected sample: %v", sample)
}
}
func TestAddSampleWrongCpuUsage(t *testing.T) {
func TestAddSampleNegativeCpuUsage(t *testing.T) {
cpuPrevUsage := uint64(15)
cpuCurrentUsage := uint64(10)
memCurrentUsage := uint64(200)
@ -227,8 +227,11 @@ func TestAddSampleWrongCpuUsage(t *testing.T) {
current := createStats(cpuCurrentUsage, memCurrentUsage, prevTime.Add(1*time.Second))
sample, err := NewSample(prev, current)
if err == nil {
t.Errorf("generated an unexpected sample: %+v", sample)
if err != nil {
t.Errorf("expected to sample without error %+v", err)
}
if sample.Cpu.Usage != 0 || sample.Cpu.PerCpuUsage[0] != 0 {
t.Errorf("expected usage to saturate to 0: %+v", sample)
}
}