Robert Clausecker
fb16871572
libcpucycles is a microlibrary for counting CPU cycles. Cycle counts are not as detailed as Falk diagrams but are the most precise timers available to typical software; they are central tools used in understanding and improving software performance. The libcpucycles API is simple: include <cpucycles.h>, call cpucycles() to receive a long long whenever desired, and link with -lcpucycles. Internally, libcpucycles understands machine-level cycle counters for amd64 (both PMC and TSC), arm32, arm64 (both PMC and VCT), mips64, ppc32, ppc64, riscv32, riscv64, s390x, sparc64, and x86. libcpucycles also understands four OS-level mechanisms, which give varying levels of accuracy: mach_absolute_time, perf_event, CLOCK_MONOTONIC, and, as a fallback, microsecond-resolution gettimeofday. When the program first calls cpucycles(), libcpucycles automatically benchmarks the available mechanisms and selects the mechanism that does the best job. Subsequent cpucycles() calls are thread-safe and very fast. An accompanying cpucycles-info program prints a summary of cycle-counter accuracy. WWW: https://cpucycles.cr.yp.to/ Tested by: jhibbits
21 lines
1.1 KiB
Plaintext
21 lines
1.1 KiB
Plaintext
libcpucycles is a microlibrary for counting CPU cycles. Cycle counts
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are not as detailed as Falk diagrams but are the most precise timers
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available to typical software; they are central tools used in
|
|
understanding and improving software performance.
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The libcpucycles API is simple: include <cpucycles.h>, call cpucycles()
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to receive a long long whenever desired, and link with -lcpucycles.
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|
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Internally, libcpucycles understands machine-level cycle counters for
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amd64 (both PMC and TSC), arm32, arm64 (both PMC and VCT), mips64,
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ppc32, ppc64, riscv32, riscv64, s390x, sparc64, and x86. libcpucycles
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also understands four OS-level mechanisms, which give varying levels of
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accuracy: mach_absolute_time, perf_event, CLOCK_MONOTONIC, and, as a
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fallback, microsecond-resolution gettimeofday.
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When the program first calls cpucycles(), libcpucycles automatically
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benchmarks the available mechanisms and selects the mechanism that does
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the best job. Subsequent cpucycles() calls are thread-safe and very
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fast. An accompanying cpucycles-info program prints a summary of
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cycle-counter accuracy.
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