Performance issue

[110-kenichi]

Calling API is too heavy. Are there any tips?

[zalintyre]

Hello,

what do you mean by "too heavy"? Too slow? This is always relative ;) Can you provide some measurements?

Kind regards Franz

[110-kenichi]

Hi,

Too slow... Caller my app is 64bit and Callee DLL is 32bit. The DLL is transmitting data via Serial port. But, I don't sure what the DLL is doing.

Can you provide some measurements?

Do I just provide the "Native 32bit to 32bit calling time AND 64bit to 32 bit wrapper calling time" ? Please wait for a while...

Thanks

[110-kenichi]

Bottleneck code

Stopwatch stopwatch = Stopwatch.StartNew(); wrapperClient.SetRegister(pChip, dAddr, pData); //TOO SLOW stopwatch.Stop(); timespan += stopwatch.Elapsed;

32 to 32 w/ native : 0.0033695s

https://user-images.githubusercontent.com/40394569/104835613-2b2f2180-58eb-11eb-9a29-e350952c71f3.mp4

64 to 32 w/ wrapper : 22.9436008s

https://user-images.githubusercontent.com/40394569/104835618-2ff3d580-58eb-11eb-8c5c-e36530324ee5.mp4

[zalintyre]

Hello,

I'm afraid your code snippet provide not enough information to reproduce your problem.

Can you provide:

• More code samples, including code and / or documentation of the called DLL
• The output of a profiler like dotTrace
• The output of a memory investigation tool like dotMemory

The two measured times imply an increase of computation time with a factor 6800. Because LegacyWrapper runs the same code for 32bit and 64bit, it is more likely that this issue is caused either by your (operating) system or your hardware.

Kind regards Franz

[110-kenichi]

Hi,

Hmm, I would like to confirm you before profiling... you have not a performance issue on your environment?

Thanks

[110-kenichi]

Hi,

SetRegister() API is a simple VC++ API.

declspec(dllexport) BOOL stdcall SetRegister(void pChip, DWORD dAddr, DWORD dData) { if (pChip == NULL) return FALSE; return ((SoundChip )pChip)->setRegister(dAddr, dData); }

And, marshaling API is here.

[LegacyDllImport("ScciWrapper.dll")] public interface IScciWrapper : IDisposable { [LegacyDllMethod(CallingConvention = CallingConvention.StdCall)] void SetRegister(IntPtr pChip, uint dAddr, uint pData); }

I'm not sure the SoundChip->setRegister() API design. But I think there are no problem, because my 32bit app does not have any problem.

So, hot path is here in the SetRegister() API was described above.

How do you think?

I think you should not serialize primitive arguments of the SetRegister() API...?🤔 (If the wrappee API does not have a class/struct type argument, bypass serialization process)

[zalintyre]

Are you calling the DLL 5000 times in a second?

[110-kenichi]

Maybe YES.

Retro music player need to access sound control register only 1 byte at a time.

[110-kenichi]

Hi, almost resolved.

I used version 2.1 to strictly optimize. See the following optimization.

1. Used the Delegate.Invoke() of the FastDelegate.Net lib instead of the Delegate.BeginInvoke()
2. Cached the Delegate to invoke the Delegate.Invoke()
3. Changed all API's parameters to primitive value parameters ( CallData.Type, CallData.Exception member type changed to String type )
4. Used the ZeroFormatter lib instead of the BinaryFormatter. But, doesn't work... 😥

//If you optimize the latest version, could you please mention me ?

thanks,