Python interface to CPU counters on Linux

Or, a minimal wrapper around the py-perf-event2 Rust crate, using the Linux perf subsystem.

To install: pip install py-perf-event

Example

from py_perf_event import measure, measure_until_full_read, Hardware

[instructions1] = measure([Hardware.INSTRUCTIONS], sum, range(1_000_000)
print(instructions1)
[instructions2] = measure([Hardware.INSTRUCTIONS], sum, range(10_000_000))
print(instructions2)
assert instructions1 > 1_000_000
assert 7 < (instructions2 / instructions1) < 15

measure() may raise a PartialRead exception if the CPU counters were not turned on the whole time, which can happen because the CPU only has a limited number of counters it can do at a time. If you want to retry (a limited number of times) until you get a full read, use measure_until_full_read(), which will call the given callable repeatedly.

Other usage

See the tests for more examples.

Until more docs are available, you can use the underlying Rust libraries docs to see what fields are available on the Hardware and CacheId/CacheOp/CacheResult classes.

Changelog

• 0.3: Exposed the fact some reads are partial, and a way to deal with it.
• 0.2: Exposed Raw events.
• 0.1: Initial, very minimal release.