[uae] Re: New snapshot

  • From: Richard Drummond <evilrich@xxxxxxxxxxxxxx>
  • To: uae@xxxxxxxxxxxxx
  • Date: Sat, 10 Feb 2007 00:58:02 -0500

Hi Jason

On Monday 29 January 2007 04:22, Jason Rainforest wrote:
> Have you tested playing some games with the new snapshot? I have noticed
> that it's significantly slower than a previous snapshot (around
> 2006-12-03), with the same uae config. My config probably sucks for one
> or more reasons, but I'll attach it anyway (seems adequate for what I
> use an Amiga environment for, WB and some games). If anyone has tips on
> changing/adding/removing some options, or even a man/webpage which has
> some tips, I'd be most interested, thanks.
>
> I usually adjust the Cycles per Instruction to somewhere between 400 and
> 800 for a platform shooter such as Turrican 2. This is perfectly
> adequate on the earlier snapshot, whereas on the new snapshot, I can't
> manage to get a smooth framerate or audio playback. This is in 64bit
> mode on a 2.4Ghz Athlon64 X2 4600+ running Linux (Debian Sid). I don't
> think I made a profiling version (have never used that configure
> option).

There are a number of possible explanations.

For example, with a kernel configured with HZ>=250 and with frequency scaling 
enabled, then the latency of the sleep function becomes a problem (emulating 
an A500 with cpu_speed=real or adjustable won't create enough CPU load to 
keep your CPU running at the highest clock frequency). If you uncheck 'The 
don't busy wait when idle' widget in the GUI, then E-UAE won't sleep each 
frame, and latency won't be an issue (not a great solution). Another thing to 
try might be reducing the audio latency with the sound_latency= config 
option. This defaults to 100 (ms). Try setting it to 50 or even 25.

I'm working on a better solution...

Cheers,
Rich

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