SPCL activies at SC17

SC17 is over, and even though it was my 10th anniversary, it wasn’t the best of the SC series. Actually, if you ask me personally, probably the worst but I promised to not discuss details here. Fortunately, I’ll be tech papers chair with Todd Gamblin as a vice next year, so we’ll make sure to remain purely technical. The SC series is and remains strong!

SPCL was again present in many areas across the technical program. Konstantin, Tobias, Salvatore, and I were involved in many things. Here are the thirteen most significant appearances:

1) Sunday: Torsten presented Capability Models for Manycore Memory Systems: A Case-Study with Xeon Phi KNL and the COSMO Weather Code at the Intel HPC Developer’s conference

Room was packed and people were standing :-). Slides

2) Sunday: Salvatore presented LogGOPSim version 2 at the ExaMPI workshop

3) Monday: Tobias talks about “Improved Loop Distribution in LLVM Using Polyhedral Dependences” at the LLVM workshop [program]

4) Monday: Torsten co-presents the Advanced MPI Tutorial [program]

5) Monday: Torsten presents at the Early Career Panel how to publish [program]

6) Monday: Salvatore presents his work on SimFS at the PDSW workshop

7) Tuesday: Torsten presents the sPIN talk at the TiTech booth

8) Tuesday: Torsten talks at the 25 years-of MPI and 20 years of OpenMP celebration at the Intel booth

MPI+MPI or MPI+OpenMP is the question :-).

9) Tuesday: Torsten appears at the SIGHPC annual members meeting as an elected member (slightly late due to the Intel celebration)

10) Tuesday: Konstantin presents his poster Unifying Replication and Erasure Coding to Rule Resilience in KV-Stores at the poster reception

11) Wednesday: Torsten presents the sPIN paper in the technical program

Room was full, unfortunately, the session chair’s clock was wrong, so we started 5 mins early and people streamed in late :-(. Sorry! But that was the smallest which was wrong with this …

12) Wednesday: Salvatore presents his poster on Virtualized Big Data: Reproducing Simulation Output on Demand as ACM SRC semi finalist

13) Thursday: Edgar presents the paper Scaling Betweenness Centrality Using Communication-Efficient Sparse Matrix Multiplication in the technical program

14) Friday: Torsten co-organizes the H2RC workshop

Triple room was packed (~150-200 people during the keynote).

United airlines versus Switzerland

Since my time in the US, I am a long-standing United airlines (actually Continental) customer. I enjoyed the service and especially the modern computer system. The transparency of United operations towards their customers is just years ahead of their competition. I simply enjoy viewing the seat map, upgrade standby list, boarding pass etc. in my app or online. The even nicer feature is to see where the next plane comes from and if it is still on schedule. Yes, I’m a geek but kudos United!

Well, now I live in Switzerland (ZRH as main airport) and sometimes catch myself considering to switch. My last flight was again one of these moments … let me elaborate.

I’m usually traveling on tight schedules (because I unfortunately travel too much). This means, my plane usually starts boarding when my train arrives in the station. The time to get to the gate is very deterministic. So far, I have done this for intra-European flights, and it works great! After United sent me this email about the online check-in and app, I thought I’ll try it for overseas as well – what can go wrong!?

Well, so I checked in using the app — worked great as expected. Then, I made my first mistake: I asked at the check-in to reconfirm if that would work (I was on a very tight time schedule and needed to get breakfast in the lounge, so I could not afford to go back and forth). Ok, they told me that I need to repeat (at least parts of) the check-in procedure. So this took forever, as usual, this is why I used the app check in in the first place. So far, overall, a time loss (needed to do both, app check in and counter check in …). Uff! Also, the personnal seemed unfriendly as usual, they’re not United reps after all and it seems they don’t care much about service or the perception of the airline in general.

Ok, at the end, I proceeded to ask if United managed to buy into the Panorama lounge so I cound get breakfast. This requires a bit of explanation: the international terminal E in ZRH has no SWISS lounge. United only cooperates with SWISS afaik, which operates a lounge in A. So all Staralliance member airlines BUT United buy into the Panorama lounge which seems to be somewhat independent. There are immigration and train between A and E, so no way to quickly change terminals. So I asked if United managed to buy into the E lounge, the person at check-in reconfirmed with the apparent lead and both agreed that I could, as a Staralliance Gold member with an Eco ticket use the E lounge now (this was after I explicitly told them that this did not used to be this way). Ok, great, so I minimize the risk of missing the plane which was boarding at that time.

When showing up at the E lounge, I was told that I was not allowed in. They even tried calling check-in or a United representative – nada, apparently all at the gate. So they called the gate and got the answer “the plane is already boarding, so send the customer down”. Well, I wonder if they have breakfast for me at the gate. Total fail United, total fail! The lounge desk personnel was not further willing to continue this discussion, so I went to the gate and asked about the situation.

First, somebody from swissport (the company that United hires for managing check-in etc.): I said I wanted to complain about their process. Apparently swissport doesn’t even have a mechanism to complain and they sent me to complain to United. Seriously, they do NOT have such a channel — well, this makes it just too obvious how much they care about the customer. Ok, finally, there was a United representative at check-in (first time I saw somebody from United at the ground in ZRH actually). So I explained my situation and got a “sorry, they must have made a mistake”. It was, like often, with this latent, one could call it arrogant, “well, maybe it’s your fault and you may not have understood what they really said/meant” sub-tone. Gaaaaaaaa! At this point, I was ready to go up any wall, and nearly lost my temper. I repeated that I clearly understood what they said (even what they discussed in German) and that it was a very simple question after all. Fail #2: don’t treat customers like idiots (at least check before if they are).

Ok, accepting this mess (the boarding process was coming to an end), I explained that my major problem with this is that I didn’t have breakfast. Immediately, they pointed me to the airport shop so I can go and buy a “Gipfeli”. Wow, you screw up and then you ask me to fix it myself — great cutomer care! I asked explicitly if they wouldn’t have some snack in the plane – I got a clear no (which we all know is false). Ok, so I bought my breakfast before running into the plane … wow. I mean, it’s really not about the $20 breakfast, but the total unwillingness to (1) accept that something went wrong on their side and (2) trying to fix it, even a little bit!

And then, I get into the plane and it’s like a different planet. As usual, everybody is friendly and helpful. The purser (who is now called “International Service Manager”) asked for feedback and I told him the story. He suggested to send the story (especially since the situation in ZRH is latently suboptimal) to United. I also got to talk to the United sales manager for Switzerland for quite a while. We had very interesting discussions and I even learned something, well, I’m glad I left the problems on the ground but I’m not really looking forward to checkin in to the next flight ;-).

One more somewhat riduculous issue in the context of United vs. Switzerland is that, sometimes, one has to use SWISS as a carrier (based on either route or time). United sells code-share tickets but really nothing seems to work between the two airlines. For example, there is no way that either SWISS or United can reserve a seat for such a flight. Yes, not even SWISS can! Sorry, what!? My secretary gave up after hours on the phone … so I’m not even looking forward to the return flight the day after tomorrow (probably 9 hours in a middle seat …). Gaaa! This seems to be the most effective way to get rid of frequent fliers. Thank you.

11 SPCL@ETH activities at SC14

The Intl. Supercomputing (SC) conference is clearly the main event in HPC. It’s program is broad and more than 10k people attend annually. SPCL is mainly focused on the technical program which makes SC the top-tier conference in HPC. It is the main conference of a major ACM SIG (SIGHPC).

This year, SPCL members co-authored three technical papers in the very competitive program with several thousand attendees! One was even nominated for the best paper award — and to take it upfront, we got it! Congrats Maciej! All talks were very well attended (more than 100 people in the room).

All of these talks were presented by collaborators, so I was hoping to be off the hook. Well, not quite, because I gave seven (7!) invited talks at various events and participated in teaching a full-day tutorial on advanced MPI. The highlight was a keynote at the LLVM workshop. I was also running around all the time because I co-organized the overall workshop program (with several thousand attendees) at SC14.

So let me share my experience of all these exciting events in chronological order!

1) Sunday: IA3 Workshop on Irregular Applications: Architectures & Algorithms

This workshop was very nice. Kicked off by top-class keynotes from Onur Mutlu (CMU) and Keshav Pingali (UT) through great paper talks and a panel in the afternoon. I served on the panel with some top-class people and it was a lot of fun!

Giving my panel presentation on accelerators for graph computing.

Arguing during the panel discussion (Hadoop right now) with (left to right): Keshav Pingali (UT Austin), John Shalf (Berkeley), me (ETH), Clayton Chandler (DOD), Benoit Dupont de Dinechin (Kalray), Onur Mutlu (CMU, Maya Gokhale (LLNL). A rather argumentative group :-).

My slides can be found here.

2) Monday – LLVM Workshop

It was long overdue to discuss the use of LLVM in the context of HPC. So thanks to Hal Finkel and Jeff Hammond for organizing this fantastic workshop! I kicked it off with some considerations about runtime-recompilation and how to improve codes.

The volunteers counted around 80 attendees in the room! Not too bad for a workshop. My slides on “A case for runtime recompilation in HPC” are here.

3) Monday – Advanced MPI Tutorial

Our tutorial attendee numbers keep growing! More than 67 people registered but it felt like more were showing up for the tutorial. We also released the new MPI books, especially the “Using Advanced MPI” book which shortly after became the top new release on Amazon in the parallel processing category.

4) Tuesday – Graph 500 BoF

There, I released the fourth Green Graph 500 list. Not much new happened on the list (same as for the Top500 and Graph500) but the BoF
was still fun! Peter Kogge presented some interesting views on the data of the list. My slides can be found here.

5) Tuesday – LLVM BoF

Concurrently with the Graph 500 BoF was the LLVM BoF, so I had to speak at both at the same time. Well, that didn’t go too well (I’m still only one person — apologies to Jim). I only made 20% of this BoF but it was great! Again, very good turnout, LLVM is certainly becoming more important every year. My slides are here.

6) Tuesday – Simulation BoF

There are many simulators in HPC! Often for different purposes but also sometimes for similar ones. We discussed how to collaborate and focus our efforts better. I represented LogGOPSim, SPCL’s discrete event simulator for parallel applications.

My talk summarized features and achievements and slides can be found here.

7) Tuesday – Paper Talk “Slim Fly: A Cost Effective Low-Diameter Network Topology”

Our paper was up for Best Student Paper and Maciej did a great job presenting it. But no need to explain, go and read it here!

Maciej presenting the paper! Well done.

8) Wednesday – PADAL BoF – Programming Abstractions for Data Locality

Programming has to become more data-centric as architectures evolve. This BoF followed an earlier workshop in Lugano on the same topic. It was great — no slides this time, just an open discussion! I hope I didn’t upset David Padua :-).

Didem Unat moderated and the panelists were — Paul Kelly (Imperial), Brad Chamberlain (Cray), Naoya Maruyama (TiTech), David Padua (UIUC), me (ETH), Michael Garland (NVIDIA). It was a truly lively BoF :-).

But hey, I just got it in writing from the Swiss that I’m not qualified to talk about this topic — bummer!

The room was packed and the participation was great. We didn’t get to the third question! I loved the education question, we need to change the way we teach parallel computing.

9) Wednesday – Paper Talk “Understanding the Effects of Communication and Coordination on Checkpointing at Scale”

Kurt Ferreira, a collaborator from Sandia was speaking on unexpected overheads of uncoordinated checkpointing analyzed using LogGOPSim (it’s a cool name!!). Go read the paper if you want to know more!

Kurt speaking.

10) Thursday – Paper Talk “Fail-in-Place Network Design: Interaction between Topology, Routing Algorithm and Failures”

Presented by Jens Domke, a collaborator from Tokyo Tech (now at TU Dresden). A nice analysis of what happens to a network when links or routers fail. Read about it here.

Jens speaking.

11) Thursday – Award Ceremony

Yes, somewhat unexpectedly, we go the best student paper award. The second major technical award in a row for SPCL (after last year’s best paper).

Happy :-).

Coverage by Michele @ HPC-CH and Rich @ insideHPC.

ExaMPI’13 Workshop at SC13

I wanted to highlight the ExaMPI’13 workshop at SC13. It was a while ago but it is worth reporting!

The workshop’s theme was “Exascale MPI” and the workshop addressed several topics on how to move MPI to the next big divisible-by-10^3 floating point number. Actually, for Exascale, it’s unclear if it’s only FLOPs, maybe it’s data now, but then, we easily have machines with Exabytes :-). Anyway, MPI is an viable candidate to run on future large-scale machines, maybe at a low level.

A while ago, some colleagues and I summarized the issues that MPI faces in going to large scale: “MPI on Millions of Cores“. The conclusion was that it’s possible to move forward but some non-scalable elements need to be removed or avoided in MPI. This was right on topic for this workshop, and indeed, several authors of the paper were speaking!

The organizers invited me to give a keynote to kick off the event. I was talking about large-scale MPI and large-scale graph analysis and how this could be done in MPI. [Slides]

The very nice organizers sent me some pictures that I want to share here:

My keynote on large-scale MPI and graph algorithms.

The gigantic room was well filled (I’d guess more than 50 people).

Jesper talking about the EPIGRAM project to address MPI needs for the future large scales.

The DEEP strategy of Julich using inter-communicators (the first users I know of).

Pavan on our heterogeneous future, very nice insights.

All in all, a great workshop with a very good atmosphere. I received many good questions and had very good discussions afterwards.

Kudos to the organizers!

Moving to Switzerland – Part 1

Oh well … the move comes closer. It’s actually much easier to move within the US (surprise!). The first part was packing everything (check!). I left nine bags of stuff (including my weightlifting set :-)) readily packed to check them into a plane at a friend’s house (thanks Cristina!). All bulkier and lighter items are in the trunk of my car (including the TV, the bar of the bar bell and other random stuff.

The highlight so far was the pickup of the car. The car is shipped with Schumacher Logistics. Everything went fine so far and the people are really nice. The trucker showed up a day early, which was fine, because I just returned from Germany (well, a looong day). He drove a gigantic truck and got lost in Champaign (he drove around while talking to me on the phone, dude …). So finally, he made it on Springfield and didn’t want to drive down the street to not scratch the cars on his truck with the trees (oh well, he had to back up). But that went well.

This middle-lane in the US is actually really useful, for example, for loading cars :-). Here are some pictures:

The truck – a seven-car carrier! Ridiculously huge.

Two cars already loaded when he came.

Inspecting our car for ridiculously small scratches. Man, this guy found all kinds of super-small scratches all over. Hope nothing more happens …

Ok, first try to load :-). I told him it wouldn’t fit …

Well, yeah, it didn’t fit (surprise). 🙂

Ok, 2nd try, lower deck. I was assuming he drives it into the middle … but …

He kinda stopped at the very end!? Oh well, I’m not a shipping pro.

The car was strapped to the truck with gigantic chains (the tires showed serious signs of pressure …).

I hope there are no bumpy streets, the distance between street and exhaust was not that great …

And there he goes … hoping for the best!

I’ll keep you posted!

Black Friday

Well, Black Friday is one of those things one has to do while living in the US. I failed so far … but this year it shall be different (after being at a delicious thanksgiving meal in Chicago). The problem is that camping the night before on the street, waiting in line forever, and fighting for the very best deals isn’t quite my thing. But there is a good trick to avoid all this and still get reasonable deals if you’re living in a village like Champaign :-).

So I got a brand-new 32 inch Toshiba flat-screen TV for just $260 (for the Europeans, that’s about 190 EUR) instead of $340 … I think it’s an amazing deal. The way to get it without a line is to drive to a small shop in a small town which still has one or two Black Friday deals. In this case, it was a very small Radio Shack in Savoy, IL. Worked great!


The TV even has two HDMI and one VGA input. Actually, I’m not really using it as TV anyway, just as a very large (and cheap) monitor :-).

An SC11 story – walking by OccupySeattle and Space Needle …

A couple of days ago was one of those nights where I went back from the parties to my (slightly remote) hotel. I was passing OccupySeattle every day … but this time it was full of police. The funniest part was that the cops told me to leave while I was just walking by … I mean, seriously, I didn’t even stop. Actually, they stopped me in order to tell me to leave. I didn’t think it was worth mentioning until I saw this. I think the whole movement is really fed by such stories in a very grim way.

The movement is interesting and the Seattle one is especially noteworthy since the weather is really bad.

Well, well … very strange. Btw., the conference was absolutely great! Well, it was a bit too small (crowded) and the Party in the Space Needle was rather disastrous (reminded me a bit of the SC08 Texas thing without food). It was the opposite though this time — there was a lot of excellent food and drinks, but there was simply no space to stand. And getting up the needle was a 1-hour effort, well, Jim and I found a secret shortcut ;-). Here is the proof:


SC11 is over now! And we even had a 1.5 hours break before SC12 started for the committee :-). It was a great show, bigger, better everything. ~5k people in the technical program and ~12k total.

PS: I know that Mount Rainier and the Space Needle can not fit on a picture like this … it’s called artistic freedom!

My self-grown citrus thingy blooms!

Huh, I came back home from a longer trip and, instead of dying, my citrus plant (not even sure what it is, either orange or grapefruit) was blooming! One step further towards the master gardener :-).

Supercomputing 2011 and 2011 Committee Meeting

Right after the conference in Tucson, I had to go the the SC11/SC12 committee meeting in Seattle. It didn’t seem useful to fly back to Champaign over the weekend (I could have spent 20 hours in planes and 6 hours at home, probably sleeping anyway. So I just stayed in Seattle over the weekend. I received very bad news during that trip but fortunately, I was around a friend and we went hiking in Seattle (thanks Frank!).

We did two day-hikes that were not trivial. Unfortunately, I had my knee injured before but it was ok. On the first day, we climbed mount SI, acutally, we climbed from the bottom to the *very* top (the rock thing on the top!!). This was quite a hike. Approximately 4000 feet height difference and three hours walking (one way). The last climb was up a massive rock wall, it was very dangerous (adrenaline!) but also very impressive and nice. We beat the mountain!

The second day hike was to a large waterfall and a lake at the top of a mountain at Lake Serene. It was just stunningly beautiful even though I got a bit wet in the waterfall, and slipping was somewhat dangerous too :-).

Here is the GPS tracking of our Lake Serene hike (my new phone rocks!):

Here are some pictures: