How do I speed up the return time of readfile?

See more:

serial-port

C++14

VC++

I am developing an application that reads a fixed packet of data from a com port at regular intervals of 50ms. I am using CreateFile and ReadFile to open and read from the port respectively. There is a tiny amount of processing that happens with the data that is read.

Because timing is vital in such an application, I decided to check how long each of the separate tasks was taking. The ReadFile function was called at every 50ms or whenever the EV_RXCHAR event happened. The processing takes hardly a millisecond. This is all good. But the ReadFile function takes on an average 15ms to return. This seems like an awful lot of time to read data from a port. I am sending data to the port through a third-party application that writes data as packets, so it can't (I think) be because of its write speed.

This becomes an issue because of the following: I did the above tests with virtual com ports. When I test it with some physical hardware, the time taken can vary from 47ms to 127ms. The hardware is a card designed to package data and send them as packets. This amount of delay causes my application to go out of sync pretty quickly.

So any suggestions as to how I can speed this up, or maybe try a different strategy would be highly appreciated.

PS: I am doing non-overlapped read and write on purpose.

What I have tried:

I don't know what to add here, so I am adding my read function code. It is in an infinite loop until instructed otherwise.

void CGCUGUIDlg::fnRead()
{
	
	while(m_bCount==true)
	{
		
		{
			
			WaitCommEvent(m_hComm,&dwEventMask,NULL);
			if(dwEventMask==EV_RXCHAR)
			{
				DWORD NoBytesRead;
				BYTE  abBuffer[100];
				if(ReadFile((m_hComm),&abBuffer,sizeof(abBuffer),&NoBytesRead,0)) //This takes over 47ms with physical hardware
				{
					midTime1 = GetTickCount();
					if(NoBytesRead==45)
					{
						
if(abBuffer[0]==0x10&&abBuffer[1]==0x10||abBuffer[0]==0x80&&abBuffer[1]==0x80)
						{
							this->fnSetData(abBuffer);
						}
						else
						{
							CString value;							
							value.Append("Header match failed");
							this->SetDlgItemText(IDC_RXRAW,value);	
						}
					}
					else if (NoBytesRead<45 && NoBytesRead>0)
					{
						CString value;
						value.Append(LPCTSTR(abBuffer),NoBytesRead);
						value.Append("\r\nInvalid Packet Size");
						this->SetDlgItemText(IDC_RXRAW,value);
					}
					
				}
				else
				{
					DWORD dwError2 = GetLastError();
					CString error2;
					error2.Format(_T("%d"),dwError2);
					this->SetDlgItemText(IDC_RXRAW,error2);
				}
				
			}
		}
		
	}
	CloseHandle(m_hComm);
		
	
}

PS: I apologise for the horrible formatting and random brackets.