MPX: software for multiplexing hardware performance counters in multithreaded programs
Hardware performance counters are CPU registers that count data loads and stores, cache misses, and other events. Counter data can help programmers understand software performance. Although CPUs typically have multiple counters, each can monitor only one type of event at a time, and some counters can monitor only certain events. Therefore, some CPUs cannot concurrently monitor interesting combinations of events. Software multiplexing partly overcomes this limitation by using time sharing to monitor multiple events on one counter. However, counter multiplexing is harder to implement for multithreaded programs than for single-threaded ones because of certain difficulties in managing the length of the time slices. This paper describes a software library called MPX that overcomes these difficulties. MPX allows applications to gather hardware counter data concurrently for any combination of countable events. MPX data are typically within a few percent of counts recorded without multiplexing.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 15006160
- Report Number(s):
- UCRL-JC-140186; TRN: US200405%%298
- Resource Relation:
- Conference: International Parallel and Distributed Processing Symposium, San Francisco, CA (US), 04/23/2001--04/27/2001; Other Information: PBD: 23 Aug 2000
- Country of Publication:
- United States
- Language:
- English
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