PPoPP 2010

The reason for my travel to India was attending the PPoPP conference which was held in conjunction with HPCA at the Indian Institute of Science in Bengaluru. Most keynotes and the opening session was shared between the two conferences and I really liked the concept of having a hardware and a programming conference jointly. It induced some interesting discussions for me. They even got a former Indian president to speak at the opening ceremony, here’s an impression:

The PPoPP program was assembled by Mary Hall who had the interesting task of assigning the reviews for a record submission (50% more than the previous year). Here are some statistics on Mary’s slide:

The conference was excellent, actually (one of?) the best conferences that I attended so far. I liked all papers (one was borderline but still ok) which is pretty rare. All in all, just excellent!

The food was great as I said before and the social event was held at an old castle (which was oddly only reachable through a terrible dirt road … and heavily guarded again). Here are some impressions from the castle and the evening program:

That’s it, a short and good conference! I also liked the single-track layout of the talks (even though some sessions were really long ;-)).

Travelling to India

In Germany is Blizzard time, the government wars citizens to avoid travel and stock up on food and medicine for four days. And I travel to India — I could have just stayed with my parents who have food and medication stocked for four months ;-). It is interesting how a series of interesting choices made me not miss any connection.


First of all, I was lucky that I chose the train to go to Frankfurt because it was the cheaper option. I heard later that more than 200 flights to Frankfurt were canceled (also from DRS?) due to severe weather. Well, I know from my experience that the German railway is never on time, thus, I planned to arrive 4 hours early in Frankfurt (enough time to have one train canceled). The train ride started 4:41 in Chemnitz and stopped 4:52 due problems with the track. Multiple stops later, it was clear that I would miss my ICE connection in Leipzig. Well, so it seemed. However, when we arrived 30 minutes late, I was told that the ICE was also late and would leave in two (2!!) minutes. So I ran and ran, and made it :-). The train ride was very productive (it’s good to have power and a table). We arrived 45 minutes late in Frankfurt, so no problem.

I flew with Emirates to Bangalore (through Dubai with a 4.5 hours layover). Well, I thought the layover was really annoying but it was the cheapest Flight available. And it turned out that it was great because we left Frankfurt more then 3 hours late! I barely caught my connection Flight in Dubai (darn, no time to look at the airport closely). About Emirates: the people at the checkin were astonishing rude and unfriendly and didn’t even look half-way like the photos on the Emirates webpage :-). However, the plane (777-300) was the best plane I ever boarded.
Each seat (Economy) had a 13” (or 14”) entertainment system (called ICE and running Linux) with a plethora of Games (approx. 100), Movies (>500), Shows and other cool things, for example a camera at the front of the aircraft! Very nice! The personnel was also friendly and the food excellent. I can recommend Emirates.

What I can not recommend is traffic in India (Bangalore). I took a taxi for the nearly 1 hour ride from the airport to the hotel. It was terrible, stressful and frightening. First, the driver did not speak any English, second the car was a complete wreck, I couldn’t even buckle up. Third, Indian traffic seems to have no rules besides “go fast”. This guy was going 100 km/h with less than 1m distance to the cars in front of us with about 4 cars and one motorcycle in parallel on a two-lane road. It was also interesting to see that the horn is significantly more important than indication lines. The driver honked about every 10 seconds (like everybody else) to either say “I’m coming through” when he passes something or “screw you” when somebody else passes or “out of my way” when somebody was in front of him or sometimes he honked just for fun without any visible reason. How weird. I tell you, this traffic is totally crazy, Italy and Moscow are totally civilized and Germany and the US are just boring in comparison :-). Indian drivers must have amazing driving skills (ok, I have seen four accidents during the drive, but still!). Never, never, never take a rental in India unless you really want to have fun. They also have the steering wheel on the wrong side, but I was not able to determine on which street-side they are supposed to go (the taxi was always in the middle). I probably doesn’t matter.

The hotel (J P Fortune) is really good (and was among the cheapest on the list of conference hotels). They have complimentary WIFI and breakfast and a pool. However, the shower water is bubbly (without soap) and a bit weird but that might be everywhere.

ICPP 2009 in Vienna

I presented our initial work on Offloading Collective Operations, which is the definition of an Assembly language for group operations (GOAL), at ICPP’09 in Vienna. I was rather disappointed by this year’s ICPP. We had some problems with the program selection already before the conference (I’ll happily tell you details on request) and the final program was not great. Some talks were very entertaining though. I really enjoyed the P2S2 workshop, especially Pete Beckman’s keynote. Other highlights (in my opinion) include:

  • Mondrian’s “A resource optimized remote-memory-access architecture for low-latency communication” (I need to talk to those guys (I did ;))
  • Argonne’s “Improving Resource Availability By Relaxing Network Allocation Constraints on the Blue Gene/P” (I need to read the paper because I missed the talk due to chaotic re-scheduling, but Narayan’s 5-minute elevator pitch summary seemed very interesting)
  • Prof. Resch’s keynote on “Simulation Performance through Parallelism -Challenges and Options” (he even mentioned the German Pirate party which I really enjoyed!)
  • Brice work with Argonne on “Cache-Efficient, Intranode Large-Message MPI Communication with MPICH2-Nemesis”
  • Argonne’s “End-to-End Study of Parallel Volume Rendering on the IBM Blue Gene/P” (yes, another excellent Argonne talk right before my presentation :))

Here are some nice pictures:
My talk at the last day was a real success (very well attended, even though it was the last talk in the conference)! It’s good to have friends (and a good talk from Argonne right before mine :-)). Btw. two of the three talks in the (only) “Information Retrieval” session were completely misplaced and had nothing to do with it, weird …

My co-author, friendly driver, and camera-man and me in front of the parliament.

EuroPVM/MPI 2009 report

This year’s EuroPVM/MPI was held in Helsinki (not quite, but close to it). I stayed in Hanasaari, a beautiful island with a small hotel and conference center on it. It’s a bit remote but nicely surrounded by nature.

The conference was nice, I learned about formal verification of MPI programs in the first day’s tutorial. This technique seems really nice for non-deterministic MPI programs (how many are there?) but there are certainly some open problems (similar to the state explosion of thread-checkers). The remainder of the conference was very nice and it feels good to meet the usual MPI suspects again. Some highlights were in my opinion:

  • Edgar’s “VolpexMPI: an MPI Library for Execution of Parallel Applications on Volatile Nodes” (indeterminism is an interesting discussion in this context)
  • Rusty’s keynote on “Using MPI to Implement Scalable Libraries” (which I suspect could use collectives)
  • Argonne’s “Processing MPI Datatypes Outside MPI” (could be very very useful for LibNBC)
  • and Steven’s invited talk on “Formal Verification for Scientific Computing: Trends and Progress” (an excellent overview for our comunity)

The whole crowd:

Unfortunately, I had to leave before the MPI Forum information session to catch my flight.
Videos of many talks are available at Videos. All-in-all, it was worth to attend. Next year’s EuroMPI (yes, the conference was finally renamed after the second year in a row without a PVM paper) will be in Stuttgart. So stay tuned and submit papers!

Hot Interconnects (HOTI’09) in New York

I attended the Hot Interconnects conference for the second time and it was as great as last year! This conference is rather convincing because it is a single-track conference with only a small number of highly interesting papers. And still, the attendance is huge, unlike on some other conferences where people only come when they have to present a paper and the audience is often sparse.

I gave a talk on static oblivious InfiniBand routing which was well received (I received a lot of questions and had very interesting discussions, especially during the breaks). Other highlights of the conference (in my opinion) were:

  • Fulcrum’s impressive 10 GiB FocalPoint switch design (the switch has full bandwidth at 10 GiB/s line-rate, real 10 GiB/s not 8 ;))
  • A paper about the implementation of collective communication on BG/P (I was hoping for a bit more theoretical background and a precise model of the BG/P network)
  • Some talks on optical networking were rather interesting
  • The panel about remote memory access over converged Ethernet was rather funny. Some people are seriously trying to implement the <irony> simple and intuitive </irony> OFED interface to Ethernet. I am wondering which real application (not MPI) uses OFED as communication API?

Here are some commented pictures:
View from the Empire State Building (credits go to Patrick!).

Another view from Empire State, the red arrow points at the conference location (the Credit Suisse Palace).

Times square (I think).

The Empire State “tip”.

Another downtown view.

The Empire State foyer.

I feel like in Paris ;).

We saw this scary building without windows as we walked from The Empire State down to the World Trade Center Site (weird).
*yeah* (seen next to the WTC site).

All we could see from the WTC site. It was not worth the long walk … but we talked anyway most of the time so this paid off.

The Wall Street (should be closed immediately!).

The subway is rather scary … seriously, New York!? Why do they have such a bad subway …

View from my (extremely cheap) hotel room. It was awesome, really!

The Credit Suisse Palace from the inside. Somebody has too much money (still).

IPDPS’09 report

I’m just back from IPDPS 2009. Overall, it was a nice conference, some ups and downs included as usual. I had several papers at workshops from which I had to present three (I was planning on two only, but one of my co-authors fell sick and couldn’t attend). They were all very well received (better than I hoped/expected).

I’m attending the CAC workshop since several years and have been surprised pleasantly each year. It only has high-quality papers and about 50% acceptance rate (be very careful with this metric, some of the best conferences in CS have a very high rate ;)). This year’s program was nicely laid out. The keynote speaker, Wu Feng, presented his view on green computing, and my talk was next. It was a perfect fit — Wu pretty much asked for more data, and I presented the data of our (purely empirical) study. My other talk presented the work on NBC of the group in Aachen – nicely done, I like the idea with the Hamiltonian path numbering but am wondering if one could do better (suggestions for a proof idea are welcome!).

Some talks were remarkable: Ashild’s talk about “Deadlock-Free Reconfiguration” was very interesting for me. Brice’s talk about “Decoupling Memory Pinning from the Application” reminded me a bit of the pipelined protocol in Open MPI, I’m not sure if I like it or not because it seems to hinder overlapping of computation and communication. The last talk about improving the RDMA-based eager protocol is a hybrid between eager and rendezvous for often-used buffers (each buffer has a usage-count and is registered after some number of uses). However, the empirical result data seemed to indicate that this only makes sense for larger buffers. And I agree to D.K. Panda’s comment that one could just decreases the protocol switching point for all considered applications. However, the idea could be very interesting for some applications with varying buffer usage.

It was in Rome this year and I don’t like Rome. I think it’s the dirtiest European city I know, and I had to stay for a week. The catering at IPDPS was bad as usual (only not-so-good cookies in coffee breaks and a unspectacular dinner). But I wasn’t there for the food anyway.

The main track was ok. I didn’t agree with some of the best paper selections. The OS jitter talk was interesting and contained some new data, however, it wasn’t clear what the new fundamental findings were. I suppose I have to read the paper. Some other theoretical papers seemed interesting, but I also need to read the articles. The panel was nice, I mostly agreed to Prof. Kale who stated that caches are getting much less important and Prof. Pingali who wants to consider locality. I seriously wonder what happened to all those dataflow architectures – I think they are a worthwile alternative to multicore systems. I was following Nir Shavit’s activities already, and I liked his keynote presentation about TM, even though there are obvious open problems.

Friday’s LSPP workshop was very interesting too. I’ve been the second year in this workshop and like it a lot (large-scale processing seems to gain importance). I enjoyed Abhinav’s talk who perfectly motivated my talk (it was right after his) and I enjoyed the lively discussion during and after my talk (sorry for delaying the schedule). I’m also happy to see that there is now an asynchronous profiling layer for the cell messaging layer (mini-cell-MPI).

I did not enjoy the flight back … Italy is awful (train runs late, airport was overcrowded and super-slow, boarding was a catastrophe because I was on the waiting list until 5 minutes before departure, …). But I was able to upgrade to first class in the US so that my last flight was at least comfortable. Here are some pictures from a five hour walk through Rome. We didn’t really pay attention because we were busy chatting :):

The Spanish steps (don’t ask … it was on the map).

Some random river …

Yep, I was there (we think it’s the Vatican in the background).

That’s simple — the collosseum (and some arch).

The view from my hotel. I couldn’t stay in the conference hotel because it was overbooked. I wasn’t mad because this one was significantly cheaper and nicer :).

Fun with the N810’s GPS

I never really used the GPS feature of the N810. It sucked badly when I got it, but it seems to be ok now. So I tried to record a walk from my home to the next grocery store – and it worked like a charm (ok, the fix took quite a while but that’s ok. I used MaemoMapper to record the data and was even able to visualize the route:

I just say: sweet! — something more to play with ;).

Some random facts:
Length: 2.21 miles
Vertical up: 1171.3 ft
Vertical down: 1154.9 ft

Oh man, National car rental is so cool ….

They had a Mustang convertible for me … how nice. Some pictures below … I love this car.

Isn’t it sweet?

And it was just the right weather to go topless *yay*.

It had even a nicer steering wheel than the other Mustangs – and you should hear the sound. Oh man, a car has to sound nice and deep and manly (not like Donald Duck – some know of you what I mean).

and it also looks kinda aggressive 😉

The Cisco Headquarters in San Jose

Now that I’ve been here multiple times, I thought I just have to try the thing they call “Cisco Burger” in their cafeteria :). So I got one and must say that it’s not better than most American burgers I had before (but what did I expect). Here’s a picture for completeness:

First Class to San Francisco

Yeah, I tried to save money for the lab and booked the cheapest flight from Indianapolis to San Francisco to attend the nth MPI Forum. It was only $120, but really really stupid. The flight consisted of two legs, Indianapolis ti Philadelphia (YES PHL! East coast *hmpf*) and then Philadelphia to San Francisco (>6 hrs). Oh man, I didn’t realize this when I booked. My colleague took a more expensive direct flight which left one hour later while arriving three hours earlier :). Ah, anyway – I got a complimentary first class upgrade on this flight – so it was awesome. Flying first class is actually better than working at home because there are people who serve you drinks and food (obviously as much as you want). The only missing thing was Internet – but anyway – it’s better than an office. I got a lot of work done and the flight clearly ended to quickly.

Just for documentation services, here is the lunch that US Airways served (not quite like in a restaurant but actually not bad). I was again updated recently and they had really excellent fish.