1 / 7

Atlas S oftware Structure

Atlas S oftware Structure. Complicated system maintained at CERN Framework for Monte Carlo and real data ( A thena) MC data generation, simulation and reconstruction Analysis of MC/real data CPU bound Conversion of data files (D3PD maker) Raw data (AOD/ESD) → flat ntuples ( rootuples )

bina
Download Presentation

Atlas S oftware Structure

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Atlas Software Structure • Complicated system maintained at CERN • Framework for Monte Carlo and real data (Athena) • MC data generation, simulation and reconstruction • Analysis of MC/real data • CPU bound • Conversion of data files (D3PD maker) • Raw data (AOD/ESD) → flat ntuples (rootuples) • Extreme I/O • Analysis of ntuples (root/proof) • I/O bound+CPU combination Compare these programs in Real and Virtual Systems

  2. Atlas T3 Virtual System design Dell blade server (openfiler) storage File server VM master WAN /LAN USERS VM VM VM VM Switch atlasgw User Desktops 12 Condor manager/ scheduler Proof master Proxy for cvmfs / coolDB iSCSI Switch VM VM VM VM VM VM SUSE corei7 SUSE corei7 VM 40+ VMs Batch nodes Batch 3GB memory/VM, no user login

  3. Real/Virtual Comparison designs Dell PowerEdge R710 Dell PowerEdge R710 SUSE 11.1 /Xen kernel 16 cernvm (v1.6 Xen batch SL4) 2GB memory per VM Athena with CVMFS Local File system Bonnie++ disk benchmarks(inside VM) SL5 8 core HT real Machine 36GB memory total Athena locally installed Local File system Bonnie++ disk benchmarks Read PerChr: 67955K/s Read Block: 270546K/s Random seeks: 428.9/sec Read PerChr: 55828K/s Read Block: 252955K/s Random seeks: 410/sec

  4. Athena Performance - CPU Bound • For CPU bound jobs: 10% performance loss for virtual systems • MC generation/simulation/reconstruction is CPU bound • Performance scales with CPU speed HT Athena 15.3.1.6, full MC, 1000 events

  5. D3PD Maker Performance - CPU+I/O Bound • No I/O performance loss for virtual machines with ATLAS software • Evidence for I/O performance (D3PD Maker) in virtual machines being better than in real machines (up to 20%) due to other limitations • Local HD raid array with 250 MB/s read bandwidth (block) and 440 random seeks/sec can’t provide enough I/O,  Performance peaks at 6 jobs; performance loss noticeable at 3 jobs relative to Virtual RAM disk. Egamma D3PD Maker, 1000 events HT *All memory caches cleared before each run

  6. iostat from real machines when 8 parallel D3PD jobs on real/virtual

  7. Proof performance

More Related