PodStartupLatency_density display "0" for create_to_schedule, schedule_to_watch, schedule_to_run

[sonyafenge]

What happened:
run perf-tool to collect data and get "0" for create_to_schedule, schedule_to_watch, schedule_to_run in PodStartupLatency_density

{
  "version": "1.0",
  "dataItems": [
    {
      "data": {
        "Perc50": 0,
        "Perc90": 0,
        "Perc99": 0
      },
      "unit": "ms",
      "labels": {
        "Metric": "create_to_schedule"
      }
    },
    {
      "data": {
        "Perc50": 0,
        "Perc90": 0,
        "Perc99": 0
      },
      "unit": "ms",
      "labels": {
        "Metric": "schedule_to_run"
      }
    },
    {
      "data": {
        "Perc50": 1065.04784,
        "Perc90": 1839.179751,
        "Perc99": 4386.837107
      },
      "unit": "ms",
      "labels": {
        "Metric": "run_to_watch"
      }
    },
    {
      "data": {
        "Perc50": 0,
        "Perc90": 0,
        "Perc99": 0
      },
      "unit": "ms",
      "labels": {
        "Metric": "schedule_to_watch"
      }
    },
    {
      "data": {
        "Perc50": 1845.589615,
        "Perc90": 2706.534456,
        "Perc99": 5534.832105
      },
      "unit": "ms",
      "labels": {
        "Metric": "pod_startup"
      }
    }
  ]
}

What you expected to happen:
create_to_schedule, schedule_to_watch, schedule_to_run has correct latency data
How to reproduce it (as minimally and precisely as possible):

Anything else we need to know?:
from code, scheduletime is getting from event:

for _, event := range schedEvents.Items {
		key := createMetaNamespaceKey(event.InvolvedObject.Namespace, event.InvolvedObject.Name)
		if _, exists := p.podStartupEntries.Get(key, createPhase); exists {
			if !event.EventTime.IsZero() {
				p.podStartupEntries.Set(key, schedulePhase, event.EventTime.Time)
			} else {
				p.podStartupEntries.Set(key, schedulePhase, event.FirstTimestamp.Time)
			}
		}
	}

Environment:

• Arktos version (use kubectl version):
• Cloud provider or hardware configuration:
• OS (e.g: cat /etc/os-release):
• Kernel (e.g. uname -a):
• Install tools:
• Network plugin and version (if this is a network-related bug):
• Others: