Apache Mesos is a resource management system for large data centres, initially developed by UC Berkeley, and now maintained under the Apache Foundation umbrella. It is widely used in the industry by ...companies like Apple, Twitter, and Airbnb and it is known to scale to 10 000s of nodes. Together with other tools of its ecosystem, such as Mesosphere Marathon or Metronome, it provides an end-to-end solution for datacenter operations and a unified way to exploit large distributed systems. We present the experience of the ALICE Experiment Offline & Computing in deploying and using in production the Apache Mesos ecosystem for a variety of tasks on a small 500 cores cluster, using hybrid OpenStack and bare metal resources. We will initially introduce the architecture of our setup and its operation, we will then describe the tasks which are performed by it, including release building and QA, release validation, and simple Monte Carlo production. We will show how we developed Mesos enabled components (called "Mesos Frameworks") to carry out ALICE specific needs. In particular, we will illustrate our effort to integrate Work Queue, a lightweight batch processing engine developed by University of Notre Dame, which ALICE uses to orchestrate release validation. Finally, we will give an outlook on how to use Mesos as resource manager for DDS, a software deployment system developed by GSI which will be the foundation of the system deployment for ALICE next generation Online-Offline (O2).
iSpy: a powerful and lightweight event display Alverson, G; Eulisse, G; McCauley, T ...
Journal of physics. Conference series,
01/2012, Volume:
396, Issue:
2
Journal Article, Conference Proceeding
Peer reviewed
Open access
iSpy is a general-purpose event data and detector visualization program that was developed as an event display for the CMS experiment at the LHC and has seen use by the general public and teachers ...and students in the context of education and outreach. Central to the iSpy design philosophy is ease of installation, use, and extensibility. The application itself uses the open-access packages Qt4 and Open Inventor and is distributed either as a fully-bound executable or a standard installer package: one can simply download and double-click to begin. Mac OSX, Linux, and Windows are supported. iSpy renders the standard 2D, 3D, and tabular views, and the architecture allows for a generic approach to production of new views and projections. iSpy reads and displays data in the ig format: event information is written in compressed JSON format files designed for distribution over a network. This format is easily extensible and makes the iSpy client indifferent to the original input data source. The ig format is the one used for release of approved CMS data to the public.
CMS software consists of over two million lines of code actively developed by hundreds of developers from all around the world. Optimal build, release and distribution of such a large-scale system ...for production and analysis activities for hundreds of sites and multiple platforms are quite a challenge. Its dependency on more than hundred external tools make its build and distribution more complex. We describe how parallel build of software and minimal distribution size dramatically reduced the time gap between software build and installation on remote sites, and how producing few big binary products, instead of thousands of small ones, helped finding out the integration and runtime issues.
CMS data quality monitoring web service Tuura, L; Eulisse, G; Meyer, A
Journal of physics. Conference series,
04/2010, Volume:
219, Issue:
7
Journal Article
Peer reviewed
Open access
A central component of the data quality monitoring system of the CMS experiment at the Large Hadron Collider is a web site for browsing data quality histograms. The production servers in data taking ...provide access to several hundred thousand histograms per run, both live in online as well as for up to several terabytes of archived histograms for the online data taking, Tier-0 prompt reconstruction, prompt calibration and analysis activities, for re-reconstruction at Tier-1s and for release validation. At the present usage level the servers currently handle in total around a million authenticated HTTP requests per day. We describe the main features and components of the system, our implementation for web-based interactive rendering, and the server design. We give an overview of the deployment and maintenance procedures. We discuss the main technical challenges and our solutions to them, with emphasis on functionality, long-term robustness and performance.
CMS Geometry Through 2020 Osborne, I; Brownson, E; Eulisse, G ...
Journal of physics. Conference series,
01/2014, Volume:
513, Issue:
2
Journal Article
Peer reviewed
Open access
CMS faces real challenges with upgrade of the CMS detector through 2020 and beyond. One of the challenges, from the software point of view, is managing upgrade simulations with the same software ...release as the 2013 scenario. We present the CMS geometry description software model, its integration with the CMS event setup and core software. The CMS geometry configuration and selection is implemented in Python. The tools collect the Python configuration fragments into a script used in CMS workflow. This flexible and automated geometry configuration allows choosing either transient or persistent version of the same scenario and specific version of the same scenario. We describe how the geometries are integrated and validated, and how we define and handle different geometry scenarios in simulation and reconstruction. We discuss how to transparently manage multiple incompatible geometries in the same software release. Several examples are shown based on current implementation assuring consistent choice of scenario conditions. The consequences and implications for multiple/different code algorithms are discussed.
The CMS experiment at LHC has a very large body of software of its own and uses extensively software from outside the experiment. Understanding the performance of such a complex system is a very ...challenging task, not the least because there are extremely few developer tools capable of profiling software systems of this scale, or producing useful reports. CMS has mainly used IgProf, valgrind, callgrind and OProfile for analysing the performance and memory usage patterns of our software. We describe the challenges, at times rather extreme ones, faced as we've analysed the performance of our software and how we've developed an understanding of the performance features. We outline the key lessons learnt so far and the actions taken to make improvements. We describe why an in-house general profiler tool still ends up besting a number of renowned open-source tools, and the improvements we've made to it in the recent year.
CMS has had an ongoing and dedicated effort to optimize software performance for several years. Initially this effort focused primarily on the cleanup of many issues coming from basic C++ errors, ...namely reducing dynamic memory churn, unnecessary copies/temporaries and tools to routinely monitor these things. Over the past 1.5 years, however, the transition to 64bit, newer versions of the gcc compiler, newer tools and the enabling of techniques like vectorization have made possible more sophisticated improvements to the software performance. This presentation will cover this evolution and describe the current avenues being pursued for software performance, as well as the corresponding gains.
During the last year the CMS experiment engaged in consolidation of its existing event display programs. The core of the new system is based on the Fireworks event display program which was by-design ...directly integrated with the CMS Event Data Model (EDM) and the light version of the software framework (FWLite). The Event Visualization Environment (EVE) of the ROOT framework is used to manage a consistent set of 3D and 2D views, selection, user-feedback and user-interaction with the graphics windows; several EVE components were developed by CMS in collaboration with the ROOT project. In event display operation simple plugins are registered into the system to perform conversion from EDM collections into their visual representations which are then managed by the application. Full event navigation and filtering as well as collection-level filtering is supported. The same data-extraction principle can also be applied when Fireworks will eventually operate as a service within the full software framework.
Geneva, 10 September 2008. The first beam in the Large Hadron Collider at CERN was successfully steered around the full 27 kilometers of the world's most powerful particle accelerator at 10h 28 this ...morning. This historic event marks a key moment in the transition from over two decades of preparation to a new era of scientific discovery2. From 9:44 am CET attention of the CMS physicists in the control room is drawn to the CMS event display -the "eyes" of the detector. We observe the tell-tale splash events (see figure 1 and 2), the beam gas and beam halo muons. We see in real time how the beam events become more and more clean as the beam is corrected. This paper describes the key component of the CMS event display: IGUANA - a well-established generic interactive visualisation framework based on a C++ component model and open-source graphics products. We describe developments since the last CHEP, including: online displays of the first real beam gas and beam halo data from the LHC first beam, flexible interactive configuration, integration with CMSSW framework, event navigation and filtering. We give an overview of the deployment and maintenance procedures in the commissioning and early detector operation and how the lessons learnt help us in getting ready for collisions.
Fireworks, the event-display program of CMS, was extended with an advanced geometry visualization package. ROOT's TGeo geometry is used as internal representation, shared among several geometry ...views. Each view is represented by a GUI list-tree widget, implemented as a flat vector to allow for fast searching, selection, and filtering by material type, node name, and shape type. Display of logical and physical volumes is supported. Color, transparency, and visibility flags can be modified for each node or for a selection of nodes. Further operations, like opening of a new view or changing of the root node, can be performed via a context menu. Node selection and graphical properties determined by the list-tree view can be visualized in any 3D graphics view of Fireworks. As each 3D view can display any number of geometry views, a user is free to combine different geometry-view selections within the same 3D view. Node-selection by proximity to a given point is possible. A visual clipping box can be set for each geometry view to limit geometry drawing into a specified region. Visualization of geometric overlaps, as detected by TGeo, is also supported. The geometry visualization package is used for detailed inspection and display of simulation geometry with or without the event data. It also serves as a tool for geometry debugging and inspection, facilitating development of geometries for CMS detector upgrades and for SLHC.
PDF
