Conference Reports

SC07 Summary: Burned out in Reno

Fear and Loathing in Reno

I usually write a very long detailed summary of the SC, but I'm hoping to make this one a bit shorter. It's not that SC07 wasn't good - it was. It's not that Reno was bad - it was. It's that I'm utterly burned out and still trying to recover. I've never been so tired after a Supercomputer conference before. I actually think that's a good thing (Doug will be expounding on why). If I managed to sleep 4 hours a night, I was lucky. If I manged to actually eat one meal (or something close to it), I had a banquet. But there were some cool things at SC07 and I've hope I do them justice.

What was the IEEE thinking?

If you recall, I thought Tampa Bay was not a good location for the conference. The exhibit floor was very cramped (there were booths out in the hall), the hotels were spread all over Florida, and there was absolutely nothing to do around the conference center. Then some person who scheduled a cigar and cognac party discovered that in Tampa the cigar bars all close on Monday (nudge, nudge, wink, wink, know what I mean? know what I mean?). So I had high hopes about Reno. And let's not forget about leaky roof in the exhibit hall.

The exhibit floor while fairly large was actually split across several rooms. This kind of spread things out a bit, but at least all of the exhibitors were in one place. But, once again, the hotels were spread out. However, the IEEE committee did a good job in providing luxury coaches to and from the hotels and the convention center. On the negative side, if you had a meeting with a company that had a "whisper suite" or meeting room, you were virtually guaranteed to walk a bit since they were all well away from the conference center. All of them were in the hotels which meant that you had to negotiate through the casino maze to find them. Of course this was the fault of the hotels and not IEEE, but I can't tell you how hard it was to wander through the casinos trying to find a specific room. Reno itself had a good number of restaurants and places to go (I went to the Beowulf Bash at a cool Jazz Bar -- nice place).

However, my overall opinion of Reno, if you haven't guessed by now, was that it's not the best place to hang out. So it looks like IEEE is 0 for 2 over the last two years. Next year's SC is in Austin, which I know has lots of good restaurants, places to go, etc. So let's hope that IEEE can pull this one out of their a** because their recent track record is not good (with me anyway). But my intention is not to complain about the location, etc. The conference is about HPC, so let's talk about that.

Themes and Variations

I always try to find a theme in the SC conference but if you read my blogs you will find out that I actually found 3 themes at SC07. They are,

  • Green Computing
  • Heterogeneous Computing
  • The Personal SuperComputer

Green Computing (but why aren't the boxes Green?)

The world seems to be captivated by everything Green (that is after being captivated by the melt down of Brittany Spears). We're all looking for ways to improve our use of natural resources and reduce our green house gas emissions and HPC (High Performance Computing) is no exception. Everywhere you walked on the floor you saw companies stating how they improved the power consumption and cooling of systems. I think I even saw a company that claimed the color of their 1U box was specifically chosen to reduce the power consumption and cooling. While I'm exaggerating of course, almost all companies claimed that their products were redesigned to make them more green. In my opinion, some of these claims were warranted and some were not.

{mosgoogle right}

Green Computing will become a mantra for many customers now and in the future and with good reason - power and cooling are reaching epic proportions. Many data centers can't produce enough cooling for the compute density that vendors can deliver. Sometimes the problem is there just isn't cooling air but many times it's not enough pressure to push the cool air to the top of the rack. APC has done a tremendous amount of research and development to understand the power and cooling of high density data centers. For example APC explains that for racks with conventional front to back cooling with power requirement of 18kW per rack (fairly dense rack), the rule of thumb for cooling requirements is about 2,500 cfm (Cubic Feet per Minute) of cooling air through the rack. Also, they go on to explain that a conventional perforated cooling tile for under the floor cooling can only provide about 300 cfm of cooling. This means you need 8 tiles to cool a single rack! On the other hand, grated tiles can provide up to about 667 cfm of cooling air to a rack, only requiring about 4 tiles to cool a single rack. Either way, the cooling requirements are rather large for high density systems.

Don't forget that if you have 2,500 cfm of air going in, you will have 2,500 cfm of hot air coming out. This air needs some kind of return. If you have a 12 inch round duct for the return air, 2,500 cfm requires the air move at about 35 mph! This also means the air coming out of a cooling tile is also going to have a high velocity.

So power and cooling are big deals for today's dense systems. We can and need to design data centers to better cool today's systems. I talked to a few people at the show, and a number of them were asking about liquid cooling. You can get what I call liquid cooled assist devices today from APC and from Liebert. Both devices uses liquid flowing through a device to cool air exiting the rack. Some of the devices are self-contained. That is, the liquid never leaves the device. Some of the devices rely on chilled water inside the data center (somehow this all seems like back to the future when Cray had liquid cooled systems).

So there are many ways to cool a data center - too many to discuss for this article. In addition to more efficient cooling, vendors have focused on more efficient processors that produce less heat.

Transmeta was one of the first to develop products targeted at reducing the power consumption of systems without unduly hurting performance. This lead to companies like RLX and Orion Multisystems using Transmeta processors in HPC clusters. But, unfortunately these companies didn't survive (I like to think that these companies gave their "lives" so to speak, to advance technology for the rest of us).

Today we have SiCortex who is making systems with a very large number of low power CPUs (derived from embedded 64-bit MIPS chips). They installed their first machine at Argonne National Laboratory this year and are working on delivering other systems. The approach that SiCortex has taken is to use to use large amounts of low power and slower CPUs. One of the other keys to their performance is the use of a very fast network to help applications scale to a large number of processors. At SC07 they showed their new SC072 workstation that uses their low power CPUs and networking to produce a box with a peak performance of 72 GFLOPS using less than 200W. While performance may not be earth shaking, the goal of the SC072 is to provide software developers with a platform that has a meaningful amount of cores and is identical their full production system.

The picture below in Figure One shows the inside of a SC072 workstation.

Figure One: View of the inside of SiCortex SC072 Workstation
Figure One: View of the inside of SiCortex SC072 Workstation

You can see the 12 heat sinks (heat sinks not heat sinks+fans) in the picture. Under each heat sink are 6 CPUs for a total of 72 CPUs. Each CPU is capable of 1 GFLOP of theoretical performance, so you get 72 GFLOPS in this small box. I'll be writing a follow-up article on Personal Supercomputers where I will go into more depth about the SC072. Needless to say it is one cool box (figuratively and literally).



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