If one thing can be said about Europe, is that it is quite diverse. Each country  solves or fails to solve its own problems individually, while European goals are not always well-cared for. Nevertheless, you can notice things changing. One of the areas where things have changed, is that of HPC. HPH  has always been a well-interconnected research in Europe (with its centre in CERN), but there is a catch-up going on for the European commercial market. The whole of Europe has new goals set for better collaboration between companies and research institutes with programs like Horizon 2020. This means that it becomes necessary to improve interconnections among much larger groups.

In most magazines HPC is a section of a broader scope. This is also very important as this introduces HPC to more people. Now, I’d like to concentrate on the focus magazines. There are mainly two magazines available: Primeur Magazine and HPC Today.

Primeur Magazine

De Netherlands based magazine Primeur-magazine has been around for years, with HPC-news from Europe, video-channel, knowledge-base, calendar and more. Issues of past weeks can be read online (for free), but news can also be delivered via a weekly e-mail (paid service, prices range from €125 to €4000 per company/institute, depending on size).

They focus on being a news-channel for what is going on in in the HPC-world, both in the EU and the US. Don’t forget to follow them on Twitter.

HPC Today

Update: the magazine changed its name from HPC Magazine to HPC Today.

With several editions (Americas, Europe and France), websites and TV channels, the France based HPC Today brings an actionable coverage of the HPC and Big Data news, technologies, uses and research. Subscriptions are free, as the magazine is paid-for by advertisements. They balance their articles by targeting both people who deeply understand malloc() and people who want to know what is going on. Their readers are developers and researchers from both academic and private sectors.

With the change to HPC Today the content has slightly changed according the requests from the readers: less science, more HPC news. For the rest it’s about the same.

To get an idea of how they’re doing, check the partners of HPC Magazine: Teratec, ISC events and SC conference.

Other European HPC sources

Not all information around the web is nicely bundled in a PDF. Find a small list below to help you start.

InSiDE

The German National Supercomputing Centers HLRS, LRZ, NIC publish the online magazine InSiDE (Innovatives Supercomputing in Deutschland) twice a year. The articles are available in html and PDF. It gives a good overview of what is going on in Germany and Europe. There are no ways to subscribe via e-mail, so it would be better to put it in your calendar.

e-IRG

The e-Infrastructure initiative‘s main goal is to support the creation of a political, technological and administrative framework for an easy and cost-effective shared use of distributed electronic resources across Europe.

e-IRG is not a magazine, but it is a good start to find information about HPC in Europe. Their knowledge-base is very useful when trying to get an overview what is there in Europe: Projects, Country-statistics, Computer centers and more. They closely collaborate with Primeur-magazine, so can you see some overlap in the information.

PRACE Digest

PRACE (Partnership for Advanced Computing in Europe) is to enable high impact scientific discovery, as well as engineering research and development across all disciplines to enhance European competitiveness for the benefit of society. PRACE seeks to achieve this mission by offering world class computing and data management resources and services through a peer review process.

The PRACE digest appears as twice a year as a PDF.

More?

Did we miss an important news-source or magazine? Let us know in the comments below!

When copying data from global to local memory, you often see code like below (1D data):
[raw]

if (get_group_id(0)==0) {
  for (int i=0; i < N; i++) {
      data_local[i] = data_global[offset+i]
  }
}
mem_fence(CLK_LOCAL_MEM_FENCE);

[/raw]
This can be replaced this with an asynchronous copy with the function async_work_group_copy, which results in more manageable and cleaner code. The function behaves like an asynchronous version of memcpy() you know from C++.

The Khronos registry async_work_group_copy provides asynchronous copies between global and local memory and a prefetch from global memory. This way it’s much easier to hide the latency of the data-transfer. In de example below, you effectively get free time to do the do_other_stuff() – this results in faster code.

As I could not find a good code-snippets online, I decided to clean-up and share some of my code. Below is a kernel that uses a patch of size (offset*2+1) and works on 2D data, flattened to a float-array. You can use it for standard convolution-like kernels.

The code is executed on workgroup-level, so there is no need to write code that makes sure it’s only executed by one work-item.

[raw]

kernel void using_local(const global float* dataIn, local float* dataInLocal) {
    event_t event;
    const int dataInLocalWidth = (offset*2 + get_local_size(0));
        
    for (int i=0; i < (offset*2 + get_local_size(1)); i++) {
        event = async_work_group_copy(
             &dataInLocal[i*dataInLocalWidth],
             &dataIn[(get_group_id(1)*get_local_size(1) - offset + i) * get_global_size(0) 
                 + (get_group_id(0)*get_local_size(0)) - offset],
             dataInLocalWidth,
             event);
   }
   do_other_stuff(); // code that you can execute for free
   wait_group_events(1, &event); // waits until the copy has finished.
   use_data(dataInLocal);
}

[/raw]

On the host (C++), the most important part:
[raw]

cl::Buffer cl_dataIn(*context, CL_MEM_READ_ONLY|CL_MEM_HOST_WRITE_ONLY, sizeof(float) 
          * gsize_x * gsize_y);
cl::LocalSpaceArg cl_dataInLocal = cl::Local(sizeof(float) * (lsize_x+2*offset) 
          * (lsize_y+2*offset));
queue.enqueueWriteBuffer(cl_dataIn, CL_TRUE, 0, sizeof(float) * size_x * size_y, dataIn);
cl::make_kernel kernel_using_local(cl::Kernel(*program,"using_local", &error));
cl::EnqueueArgs eargs(queue,cl::NullRange ,cl::NDRange(gsize_x, gsize_y), 
          cl::NDRange(lsize_x, lsize_y));
kernel_using_local(eargs, cl_dataIn, cl_dataInLocal);

[/raw]
This should work. Some have the preference to do local initialisation in the kernel, but I prefer not to do this JIT.

This code might not work optimal if you have special tricks for handling the outer border. If you see any improvement, please share via the comments.

Embedded processors always have had the focus on low-energy. Now a combination of Moore’s law, the frequency-wall and multi-processor developments have made it possible for these processors to compete in completely new market segments. Most notable due to impressive advancements in graphics IP.
We are now looking at four groups who are interested in learning from each other:

• The embedded processor market
• The FPGA market
• The HPC and server market
• The GPGPU market

And answer the question: how can we get more out of low-energy processors by looking at other industries?

The goal of the LEAP conference is to bring these three groups together. Creating the windows to each other and paving roads over the newly constructed bridges. This makes it one of its kind. Half of the conference is focused on quality information sharing and the other half on networking. For more information, check the website of the LEAP-conference. StreamHPC is a co-organiser.

Call for papers is now open! Programme is filled!

(if you get to Palo Alto, Manchester, Karlsruhe and Copenhagen)

We’re supporters of open standards and open discussions. When those thow come together, we melt. Therefore I’d like to share four hot conferences with you: IWOCL (Palo Alto, SF, USA), EMiT (Manchester, UK), ParallelCon (Karlsruhe, Germany), GPGPU-day 2015 (Copenhagen, Denmark).

On all these conferences I’ll be there too and are happy to meet you.

This post was shared first via the newsletter. Subscribe here.

Continue reading “Four conferences that will interest you” →

Here in Amsterdam a lot is going on around HPC. Including StreamHPC, we have companies like Vancis, Netherlands eScience Centre,  and ClusterVision, the research institute for Dutch HPC, Surf SARA, (hosting the Dutch supercomputer) and the very busy Amsterdam IX.

Here in Amsterdam we’re focused on building up more local companies around big compute and big data. I’d like to give two examples. One is Scyfer, an academic startup specialised in deep learning. They’ve developed algorithms to more efficiently train neural networks and help their customers find answers quicker. The second is Euvision Technologies, who developed unique computer vision solutions. Last year it has been sold to Qualcomm, for tens of millions.

We welcome new companies to Amsterdam, to further build up the HPC-ecosphere. If you have a company and are seeking a good location, contact us to talk about HPC in Amsterdam.There are many opportunities to develop in Europe, and we’re open for partnerships in new markets.

If you want to start your own HPC-related startup, Amsterdam thinks of you! There are three steps to do:

1. Go to the Venture café on 30 April
2. Apply for the bootcamp
3. Become our neighbours
4. Build your own HPC startup

Ping me, if you want advice on which preparations you need to make, before you can make such big decision. I like to have an open discussion, so please use the comment-area below for what you think of HPC in Amsterdam and building companies.

The new Hawaii-based GPUs from AMD (Radeon R9 2xx, FirePro W9100 and Firepro S9150) have a lot of improvements, one being a new OverDrive 6 (AMD’s version of NVIDIA GPU Boost). Problem is that it’s not supported yet in the Linux drivers and you will get too low performance – it probably will be solved in the next version. Luckily there is od6config, made by Jeremi M Gosney.

Do the below steps to get the GPU at normal speed.

1. Download the zip or tar.gz from http://epixoip.github.io/od6config/ and unpack.
2. Go to the directory where you unpacked the archive.
3. run:

   make

4. run:

   sudo make install

5. check if it’s needed to fix the power management:

   od6config --get clocks,temp,fan

6. if the values are too low, run:

   od6config --autofix --set power=10

7. check if it worked:

   od6config --get clocks,temp,fan

Only OverDrive6 devices are set, devices using OverDrive5 will be ignored.

The PowerTune of 10 was what we found convenient for us, but you might find better values for your case. There are several more options, which are on the homepage of 0d6config. You need to run “od6config –autofix –set power=10” on each reboot.

Remember it’s third party software, so no guarantees to you and no “you killed my GPU” to us.