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Performance Counters
From dankwiki
- Normally driven through MSRs
- RDPMC instruction: http://www.x86.org/secrets/opcodes/rdpmc.htm
- FreeBSD includes libpmc as part of the base system
- On Linux, we have libpfm from perfmon2
- This is the preferred way we get at TSC (TSC has fallen out of favor, though)
- Collectors include oprofile and perf.
| Counter | Introduced | Description |
|---|---|---|
| MACHINE_CLEARS.ASSIST_FUSION | Core i7 | Number of macro-fusions performed |
| LSD.UOPS | Core i7 | Number of μops delivered by the Loop Stream Decoder |