[MPlayer-users] Re: IS SMP support for X264 decoding possible

[Matthias Wieser]

Rich Felker wrote:
> On Tue, Sep 19, 2006 at 11:18:18AM +0400, Vladimir Mosgalin wrote:
> > Hi Rich Felker!
> >
> > On 2006.09.19 at 03:09:35 -0400, Rich Felker wrote next:
> > > The reason is that it's slower except on SMP,

How much? 1%? What about
num_threads = num_cpu_cores?

But I think it's the same with the aspect ratio: (If your CPU only has one 
core/if your monitor has an AR of 4:3) then lets assume everyone else has 
(only one core/a monitor with AR of 4:3)...

> > > impossible to debug, 

*impossible* (how does it come that I have seen many quite usable multi 
process/thread software?) to debug or slightly harder to debug?

> > > and just ugly.

A friend of mine is doing computational fluid dynamics (CFD). Using *many* 
threads or processes is not ugly but the only solution if you don't want to 
wait a year for a single simulation :-)



> > Well, dual-core cpus rock modern desktops, and soon four-core desktops
> > cpus will come both from intel and amd... /me thinks argument about
> > beeing "faster" without threads doesn't apply anymore..
>
> And I think you're full of it. Unlike idiot windows gamer kiddies, we
> do not assume everyone buys a new computer every year or even every 10
> years.

You don't have to assume anything. It's just a matter of fact that Intel, 
IBM, AMD, Sun,... are selling dual-core CPUs for more than a year now. 
Mplayer supporting SSE2 does not mean that everyone has to buy a new 
computer, too. But some people own SSE2 CPUs and some own dual core CPUs.


> Also multi-core is just idiotic. It wastes power.

No, often it saves power.
If you want to design a CPU with speed X on modern software you have two 
options:
A dual core CPU with two simple CPU cores or a single core CPU with an 
extremely highly sophisticated single CPU core. The first one will probably 
be much more power efficient. e.g. a 2GHz Athlon X2 runs probably much 
cooler than a hypothetical 4GHz Athlon 64 or a much improved and much 
larger new 3GHz cpu core.

That's the reason everyone is going multi-core: It's just more efficient to 
use many smaller cores than one super-duper- 500mm^2 monster core. There 
are practical limits in instruction level parallellism.

> The smartest use of 
> a multicore system (aside from leaving it on the shelf) is leaving all
> but one core idle.

Your definition of "smartest" seems to be slightly strange...

Regards,
  Matthias