potential solution to hyperthreading reporting error

[adgubrud]

Previous approach was to use lscpu output to provide the logical CPU count and compare that with the product of the number of physical cores active and the number of sockets active. Older kernels seem to account for only online CPUs in the logical CPU count but newer kernels (e.g. 6.8) count the number of logical CPUs available in the whole system, regardless of if they are active or not.

Since this approach has been working so far (to an extent) I tried to keep that original calculation as a default behavior. However, if the attribute "Thread(s) per core" is available from lscpu, we use that to determine if hyperthreading is enabled. As a fallback, there is a function to enumerate the number of online cores ("On-line CPU(s) list" in lscpu), then compare that number with the number of physical cores and number of sockets if the number of online cores is less than what is reported with the "CPU(s)" attribute from lscpu.

[Copilot]

Pull Request Overview

This PR enhances hyperthreading detection by leveraging the Thread(s) per core attribute and falling back to an online-CPU range when needed.

• Add extraction and parsing of "On-line CPU(s) list" and "Thread(s) per core" from lscpu output
• Adjust hyperthreadingFromOutput to prefer online-CPU counts and threads-per-core before legacy logical-CPU checks
• Introduce parseCPURanges and parseCPURangeCount helpers for CPU-range string parsing

Comments suppressed due to low confidence (2)

internal/report/table_helpers.go:456

• [nitpick] Consider renaming onlineCpus to onlineCPUListStr or similar to clarify that this variable holds the raw range string, not the parsed count.

	onlineCpus := valFromRegexSubmatch(outputs[script.LscpuScriptName].Stdout, `^On-line CPU\(.*:\s*(.+?)$`)

internal/report/table_helpers.go:2052

• Add unit tests for parseCPURanges (and parseCPURangeCount) covering edge cases such as empty strings, invalid formats, overlapping ranges, and duplicates.

// parseCPURanges parses CPU range strings like "0-7,32-35" and returns the total count

[harp-intel]

Approach seems sound. Code looks good. I believe there is a util function that will parse the ranges for you. Please check and reuse, if applicable.

[harp-intel]

Looks like we lost the unit tests that were previously in table_helpers_test.go.

[harp-intel]

Thanks @adgubrud .