How to find event timestamp duration with respect to current time in minute and seconds?

[Abhineet]

We have splunk event having field "eventdateTime"  in format mentioned below.

for example

eventdateTime

2023-04-17 06:45:55,405

2023-04-17 06:45:52,599

2023-04-17 06:45:52,446

2023-04-17 06:45:52,208

We want to create new field "duration" that will give difference of "eventdateTime" value with current date time value in Minute seconds format i.e( duration = 4Min:10.256Sec)

For Example:

 eventdateTime = 22023-04-17 06:51:19,950

current date time = 2023-04-17 06:53:39,000

duration = 2Min:19.050Sec

[woodcock]

| eval duration=now()-strptime(eventdateTime,"%F %T,%3N")
| fieldformat duration=tostring(duration ,"duration")

[ITWhisperer]

| eval duration=tostring(now()-strptime(eventdateTime,"%F %T,%3N"),"duration")