[MPlayer-dev-eng] Re: Make -nortc the default?

[Uoti Urpala]

On Fri, 2006-09-08 at 20:06 -0700, RC wrote:
> On Sat, 09 Sep 2006 04:33:22 +0300
> Uoti Urpala <uoti.urpala at pp1.inet.fi> wrote:
> 
> > I don't believe the numbers in that mail. 
> 
> Believe those numbers or not, the result is very real.
> 
> top shows a huge difference, it's just not as easy to include that
> output in an e-mail.

The output of top is based on the same incorrect numbers as the time
values in your old post.

> MPlayer shows the difference when other CPU-intesive apps are running,
> via jerky playback and dropping frames with -rtc, but not with -nortc.

This can be caused by different scheduling: your 2.4 kernel doesn't
schedule the process immediately when the rtc fd becomes readable and
gives longer time slices rather than low latency in the -rtc case. It
doesn't say anything about CPU usage.

> Mencoder shows the difference, as encoding slows down significantly when
> playing back with -rtc, but it doesn't practically at all with -rtc.

You mean running MPlayer simultaneously with it? If so then this is the
only one of your examples which could show something about real CPU use.

> Also, I've since upgraded to Slackware 10.2, and see the same behavior
> (still a 2.4.x kernel).  -rtc is a serious slowdown.

2.4 isn't that relevant any more. And on 2.4 rtc might actually be
preferable since most 2.4 kernels are compiled with HZ=100 and so rtc
can give more accurate timing.