How can I investigate a problem `kotlinx coroutines delay 10

Question

How can I investigate a problem `kotlinx coroutines delay 100 ` sometimes works 10 seconds Some breakpoint

bezrukov · Answer

it doesn t do any work it simply re schedule coroutine with specified delay So there are some factors affecting real delay 1 Dispatcher may be busy so you can review all running coroutines Probably via DebugProbes dumpCoroutines 2 CPU sleep affects delays so you have to determine whether it s sleeping or not 3 Same as 1 But one level deeper assuming you re on JVM there are a lot of running threads CPU consuming so your dispatcher doesn t receive enough cpu credits

aleksey.tomin · Answer

I ve added `implementation org jetbrains kotlinx kotlinx coroutines debug 1 4 1 native mt ` but I have got an error ` app kt 33 40 Unresolved reference debug` on ``` kotlinx coroutines debug DebugProbes dumpCoroutines ``` < bezrukov> What I do wrong

Saul Wiggin · Answer

Should variable be a Long 100L This works for me for 10s ```GlobalScope launch delay 10000L ```

aleksey.tomin · Answer

It works slowly sometimes <https youtrack jetbrains com issue KT 43589>

aleksey.tomin · Answer

aleksey.tomin · Answer

< Saul Wiggin> `delay 3 seconds ` ```13 th done in 3 004999936s average=3 001999990153846s max=3 004999936s 14 th done in 3 003000064s average=3 002071424s max=3 004999936s 15 th done in 12 999000064s average=3 6685333333333334s max=12 999000064s 16 th done in 13 0s average=4 25175s max=13 0s 17 th done in 13 0s average=4 7663529411764705s max=13 0s```

aleksey.tomin · Answer

Oh It s a <https stackoverflow com questions 31339986 mac os x application slows down when its window has not focus>

ursus · Answer

If I might OT how would one make something time delay related but is mission critical to be precise From what I gather high level threads cannot guarantee anything since its all up to cpu scheduler s time sharing right Is the only solution something like a dedicated chip

aleksey.tomin · Answer

I use ktor client It works with delay for prevent blocking

ursus · Answer

Hm My question was general smart phone cpu I belive

bezrukov · Answer

Usually you have to work with system s power manager like Android s Linux s wakelock to schedule job that need s to be done at exact time

ursus · Answer

But that wont be exact for real say for some self driving car stuff since all cores can be occupied and then time sharing comes into place no

aleksey.tomin · Answer

I ve had the problem on macOS and it s macOS specific problem

ursus · Answer

I know the battery saver thing but I meant as OT that I believe this is a general purpose computer issue that time keeping is inexact really nevermind