Author: Allison, S.
Paper Title Page
WEPGF122 Real-Time Performance Improvements and Consideration of Parallel Processing for Beam Synchronous Acquisition (BSA) 1
 
  • K.H. Kim, S. Allison, T. Straumann, E. Williams
    SLAC, Menlo Park, California, USA
 
  Funding: Work supported by the the U.S. Department of Energy, Office of Science under Contract DE-AC02-76SF00515 for LCLS I and LCLS II.
Beam Synchronous Acquisition (BSA) provides a common infrastructure for aligning data to each individual beam pulse, as required by the Linac Coherent Light Source (LCLS). BSA allows 20 independent acquisitions simultaneously for the entire LCLS facility and is used extensively for beam physics, machine diagnostics and operation. BSA is designed as part of LCLS timing system and is currently an EPICS record based implementation, allowing timing receiver EPICS applications to easily add BSA functionality to their own record processing. However, the non-real-time performance of EPICS record processing and the increasing number of BSA devices has brought real-time performance issues. The major reason for the performance problem is likely due to the lack of separation between time-critical BSA upstream processing and non-critical downstream processing. BSA is being improved with thread level programming, breaking the global lock in each BSA device, adding a queue between upstream and downstream processing, and moving out the non-critical downstream to a lower priority worker thread. The use of multiple worker threads for parallel processing in SMP systems is also being investigated.
 
poster icon Poster WEPGF122 [1.665 MB]