Why Doesn't the Itanium Get the Respect It's Due?

happycorp wonders: "As in recent years the Itanium does well, easily beating x86 processors even at its low clockspeed (1.4Ghz). The supercomputer people are serious about benchmarking (no easily tricked microbenchmarks or reliance on closed-source commercial apps), so the discrepancy between the performance and perception of this chip is serious. With a single-CPU Itanium2 system at around $2000 their price is already reasonable, and the price would come down (and software would be ported) if the Itanium ever became a mass market chip. Having an affordable chip one step above a Xeon or Opteron in floating-point performance would not be such a bad thing for gaming enthusiasts (or 3D artists). So, the recent article on the Top 500 supercomputers list brings up a question I've been meaning to ask: Why do we see so many disparaging opinions of the Itanium processor (all those 'Itanic' jokes, etc.)?" "It seems computing enthusiasts' sentiment is set against this processor, and its likely that it's going to be abandoned sooner or later. We'll be paying for x86 compatibility indefinitely (recall the Xeon has roughly three times the number of transistors of the ppc970 for example; but we hardly get three times the performance).

These are a couple scores from the top 20, with the total gigaflops divided by the number of processors to obtain a per-processor speed:

rank processor ghz (gflops / #procs) speed #5 ppc970 2.2 (27910 / 4800) 5.81 #7 itanium2 1.4 (19940 / 4096) 4.86 #10 opteron 2.0 (15250 / 5000) 3.05 #20 xeon 3.06 (9819 / 2500) 3.92
Given this, consider what a 2 or 3 Ghz Itanium could do.

(fine print: I am not affiliated with the Itanium or the top500 list in any way)."

Comments

Itanium2

[Anonymous Coward]

I had to study the chip in one of my EE class. The technology in it is really really impressive. I love the memory architecture provisions!

Sure, it's cheap NOW.

[Proc6]

Probably because when it mattered a single CPU Itanic was more like $12,000 and not $2,000. After fucking up all their marketing and delivering strategies no one wants one anymore.

No good compilers for EPIC

[Anonymous Coward]

I may be entirely wrong, but I believe the dislike for the Itanium stems from the fact that you can't compile any decently optimized code for it. Apparently, even Intel can't create a good compiler/linker and toolkit for creating machine code that makes good use of EPIC. Even though the processor itself is more efficient and faster, the same thing compiled to machine code running side by side with an Opteron or any other x86-64 chip will see the x86 win. If somebody could come up with a decent compiler/linker that provided full EPIC optimizations, they would be bangin, but they don't have it so we don't use it.

the problem is those are well optimized benchmarks

[Surt]

The people who work on scientific applications take performance seriously. They put a lot of effort into optimization. The itanium architecture is hard to optimize for, and the compilers just aren't there yet for the general case. So you wind up with a disparity between the performance in scientific applications and general purpose applications.

Other reasons itanium can't compete:

1) Compare the performance of itanium with xeon/opteron in running native x86 code.

2) Compare the costs of building real end user systems.

3) Compare the availability of windows xp drivers.

It's a pain in the ass

[unsinged int]

to compile for Itanium. Speaking as a compiler researcher, Itanium is great for generating research papers because there are all sorts of things that you can do from a compiler perspective. The problem is, outside a research environment, someone has to implement a lot of the ideas in an Itanium compiler to make it useful. Unfortunately, most of the stuff in the Itanium research papers isn't easy to implement and most of what gets put into commercial compilers are the easily implementable ideas.

Re:It's a pain in the ass

[Jeffrey Baker]

Yeah, nice CPU, difficult for software authors. I read a paper recently wherein the authors managed to reduce L4 microkernel message passing (up to 8 bytes) to 36 clock cycles, which is far faster than any other platform. But this was done by hand, and the compiler blurted out a routine that required 508 cycles. The gulf between what you can really do with an Itanium, and what normal software writers can do with it, remains huge.

Re:Follow the herd!

[jarich]

Many people here only know what has been said on Slashdot about the Itanium. They've never used one.

I worked at a startup that was building a database ~70 gigs in size. It took 2 months to build said database. Lots and lots of very small lookups and inserts.

Memory was our bottleneck. More ram equals more speed. So we spent BIG bucks and bought a quad Itanium with 12 or 16 gigs of memory (I forget exactly how much it had).

The Itanium was slower than a dual X86 with 2 gigs of memory! And not just a little slower. We spent weeks trying to get the database optimized.

Why does no one respect the Itaniums? Intel made a slow chip. Then they released the sequel. I've already paid my dues on that line once. I'm not playing this round.