ATLAS is a particle physics experiment taking place at the Large Hadron Collider at CERN, that searches for new particles and processes using head-on collisions of protons of extraordinary high energy. Petabytes of data were recorded, processed and analyzed during the first three years of data taking, leading to up to 300 publications covering all the aspects of the Standard Model of particle physics, including the discovery of the Higgs boson in 2012.
Large scale simulation campaigns are a key ingredient for physicists, who permanently compare their data with both "known" physics and "new" phenomena predicted by alternative models of the universe, particles and interactions. This simulation runs on the WLCG Computing Grid and at any one point there are around 150,000 tasks running. You can help us run even more simulation by using your computer's idle time to run these same tasks.
On this page you can see ATLAS monitoring of the tasks running on ATLAS@Home, as well as how ATLAS@Home ("BOINC") compares to the other sites on the WLCG.
The program you will download runs simulation software inside a virtual machine hosted by your computer. The virtual machine image is ~500MB but is only downloaded once. Each workunit downloads a small set of input data and runs for approx 1 to 2 hours depending on the computer's processor speed.
Please consult or post to the message boards to learn more about the work currently available or in case of problems.
The Physics of ATLAS@Home
No knowledge of particle physics is required, but for those interested in the physics processes simulated in ATLAS@Home as well as the ATLAS experiment itself visit the ATLAS web pages.
ATLAS@Home tasks progress, for each task (number of jobs done/total number of jobs):
- Task mc15_13TeV BFilter_ckkw30.simul (10165253): 1472/59999
- Task mc15_13TeV BFilter_ckkw15.simul (10165249): 1573/59999
- Task mc15_13TeV BFilter_ckkw30.simul (10100172): 0/59999
- Task mc15_13TeV BFilter_ckkw15.simul (10100166): 0/59999
- Task mc15_13TeV BFilter_qsf025.simul (9776786): 27367/30000
- Task mc15_13TeV BFilter_renorm4.simul (9776784): 29693/30000
- Task mc15_13TeV BFilter_fac4.simul (9562105): 29908/30000
- Task mc15_13TeV BFilter_fac025.simul (9562069): 29931/30000
- Read our rules and policies
- This project uses BOINC. If you're already running BOINC, select Add Project. If not, download BOINC.
- This project also requires
VirtualBox to be installed.
- Windows: VirtualBox is included in Windows distributions of Boinc and so does not have to be installed separately.
- Mac and Linux: VirtualBox must be installed separately
- VirtualBox 5.x is required. We have seen performance issues with older versions.
- After choosing Add Project in Boinc Manager, choose ATLAS@home from the list of projects
- Then either enter details for to set up a new account, or if you have previously registered enter the existing account details.
- A reasonably powerful modern 64-bit computer with at least 4GB of memory is required to run ATLAS@Home. Enabling 64-bit virtualisation may require some changes in BIOS settings.
- In Boinc Manger set the % of processors used to be at most 50%, otherwise your computer may run out of memory.
- The work units may use a lot of network bandwidth, so a slow internet connection may reduce work unit efficiency
- The work units contact servers at CERN and outside CERN. If you are behind a firewall you will need to open access to these servers. Please contact us for details.
- If you're running a command-line version of BOINC, create an account first.
- If you have any problems, get help here.
User of the day
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New single-core tasks
Thanks for all your feedback on the future of the single-core app. We have seen that it is useful to keep it, especially for less experienced volunteers who don't want to write xml files to configure how many tasks to run.
Therefore we are directing some of the multicore WU into the single core app. These WU will use only one core but process the same number of events (100) as the multicore WU, so will run for a few hours longer than the previous single-core WU.
We have also cancelled the remaining single-core WU which were faulty or stuck on non-responding hosts. Apologies if you were actively crunching one of those.
In addition we have applied the same restrictions to the single-core app as we have on the multicore app: the minimum version of virtualbox required is 5.0.0 and there is a check that virtualisation is possible on your PC before sending WU. So if you have an old virtualbox or a PC not configured for virtualisation then you will not receive any more WU. Please see Yeti's checklist for more information in case of problems.
Thanks again for your continued contribution! 22 Nov 2016, 20:44:43 UTC · Comment
Single core tasks finished
You may have noticed that there are no single core tasks left in the queue. This is deliberate as part of our aim to simplify things by having a single app which is multicore only.
We know that there are people who like to run only single-core WU but it is possible to run multicore WU in a single-core mode through the use of app_config.xml. (set
This is not a perfect solution so if there are serious objections to deprecating the single core app we can do some tricks to send multicore WU to the single core app which will then run in single-core mode. Please let us know what you think. 10 Nov 2016, 10:50:14 UTC · Comment
New multi-core version 1.05
The new batch of multicore WU that we have require a new version of ATLAS simulation software so we had to release a new version of the multicore application. The only change is the VM image which unfortunately has grown in size to 2.3GB with the new software. 6 Oct 2016, 11:45:32 UTC · Comment
Changes to the multicore app configuration
After analysis of results from the multicore app (see this thread) we have made the following changes
- Minimum VirtualBox version required is 5.0.0
- Maximum cores reduced from 12 to 8 (this can be overridden in app_config.xml but we have seen severe performance issues above 8 cores)
- Enforced that hardware acceleration is enabled on the host. This should stop the -148 ERR_EXEC errors because WU will not be sent to these hosts.
Please continue to provide your feedback on changes we make. 13 Sep 2016, 8:09:56 UTC · Comment
Tips on how to gain better performance on the ATLAS_MCORE app
According to our test, the CPU performance (We measure the CPU performance by seconds of CPU per event. For example, the current ATLAS job running on the ATlAS_MCORE app processes 100 events, if the overall CPU time for this job is 30000 seconds, then the CPU performance is 300 seconds/event) varies to the number of cores of the vm.
In the test, we also compared the CPU performance on different Virtualbox versions.
The test result can be seen here:
The above test is done on 2 hosts, HOST1 has HT(HypherThreading) enabled, while HOST2 has HT disabled. The test result is consistent despite of whether disabling/enabling HT of the CPU.
Also, we conclude a result from the ATLAS job statistics based on the jobs from over 1 month period. The following result shows the average CPU performance on different number of cores. (ATLAS_MCORE supports up to 12 cores for now).
The benefit of using more cores in one vm is to save memory usage, but using big number of cores can also significantly reduce the CPU performance. Our test result also concludes this is a case in all cloud computing platforms, not just on ATLAS@home.
In order to have a good tradeoff between memory usage and CPU performance, we advise that you configure the cores to each ATLAS_MCORE job(VM) according to the overall cores and memory allocated to BOINC.For example,if your host allocates 12 cores to BOINC, by default, ATLAS_MCORE creates a vm with 12 cores with 12.1GB memory, but if the host has enough memory, you can customize the usage with the app_config.xml file, i.e. each vm uses 6 cores with 7.3GB memory, so that your host runs 2 vms, and the overall memory usage is 14.6GB.
You can limit the MultiCore-App by using the app_config.xml (This file needs to be put in your project/atlasathome.cern.ch/ directory).
Below is an example to limit each ATLAS_MCORE job to use only 6 Cores:
You should change these two lines to your needs:
Memory usage calculated by the ATLAS_MCORE app is by this formula:
memory = 2500 + (800* NumerOfCores)
so it is 7300MB for 6 cores.
We will also make some changes on the server side very soon:
1. Require a minimum version(5.0.0) of Virtualbox for the ATLAS_MCORE app.
2. Limit the ATLAS_MCORE app to use at most 8 cores. 6 Sep 2016, 1:23:31 UTC · Comment
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