Severe slowdown when enabling Direct on Serial port.

[hceline]

I enabled this after suggestion from another thread. The result was that previously snappy Workbench felt like wading trough mud. When opening drawers it uses several seconds to paint backdorp, which was instant before enabling direct.

So I tested with timed boot to WB desktop compleatly loaded with background-pic.
Without serial-direct it boots in 24 seconds.
With serial-direct it boots in 109 seconds.
I repeated this test several times, switching direct on and off. Tried both restarting and quitting WinUAE between tests. Result is consequently the same every time.
I must note that no access to serial port was made from amiga side during tests, I just flipped the direct switch in config. MuForce and friends where running, but not outputting anything.

Attached are UAE logs from boot with direct enabled and WinUAE-config.

[hceline]

Well, the problem went away when I switched form emulated null-modem cable to raw tcp connection.

Edit: Quick question. Should I disable RTS/CTS in Winuae-Serial settings when using tcp serial port. Or should it be kept in sync with serial preferences in WB for some reason.

[QuikSanz]

Newer serial connections use this, before was flow control. RTS/CTS should be good.

Chris

[Toni Wilen]

If emulated port is connected to physical port, direct might cause host side serial port write buffer to fill too much if Amiga side writes lots data to serial port quickly. This would stall WinUAE because it expects win32 serial API writes to finish immediately.

Direct = force 115200 (if smaller rate configured) and Amiga side sees the port as almost "immediate", any write finishes instantly.

If you only use serial port to log some data, more optimal way is to use -serlog command line parameter (with -log) which outputs all serial data to log window.

[hceline]

Originally Posted by Toni Wilen

If you only use serial port to log some data, more optimal way is to use -serlog command line parameter (with -log) which outputs all serial data to log window.

This is excellent, it does practically the same as the function I requested in the other thread about hooking RawPutChar(). Thank you so much for pointing it out.