[FFmpeg-devel] Inline ASM vs. Intrinsics

[Dave Dodge]

On Fri, May 11, 2007 at 02:17:35PM -0700, Trent Piepho wrote:
> The equal cost Itanium2 system was well under half the speed of the
> Opteron system.  And that's just capital cost!  Supporting ia64 in
> addition to the existing ia32 infrastructure has a cost too.

Yeah, the costs are a big problem for IA64.  The high end IA64
processors can cost $thousands just for the chip.  I doubt they could
sustain their sales if Opteron was actually possible for the larger
configurations.

You also get to deal with
  - limited availability of tools (many don't get ported)
  - limited functionality of tools (oprofile for "sort of" works)
  - sensitivity to firmware versions
  - the EFI booting process
  - etc.

> The Opteron was quite a bit better in facilities too.  You could fit
> a dual CPU system in one rack unit.  I don't think Itanium2 would
> pack better than 1 CPU per rack unit.

SGI's 4700 series has apparently managed to cram 20 sockets and 120
DIMM slots into a single 10U box, so with dual-core chips I guess
that's 4x the original density.  Having seen the size of an IA64 CPU
that's pretty impressive.  Granted, that 10U box is a massive 32.5
inches deep, and if you have more than one of them you presumably need
lots of extra space for the cabling; I see the racks SGI sells for it
are 45 inches deep.

> Power consumption (and thus A/C needs) were also quite a
> bit better for Opteron vs Itanium2.

Lacking a 30-amp dedicated line, we have our relatively small system
(with four 500W power supplies) plugged into a 20A wall outlet.  The
cords are, shall we say, "warm" to the touch.  It's surprisingly
quiet, though; a single 2U SunFire on the other side of the room can
pretty much drown out 8U of SGI gear a few feet behind you.

                                                  -Dave Dodge