sysdetect: Fix infinite loop for heterogeneous processors #271
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The cpu_get_cache_info() function has a check that ensures the level of cache info being acquired is within the bounds of the allowed number of memory levels PAPI supports (PAPI_MAX_MEM_HIERARCHY_LEVELS). Previously the check has used >= instead of >, preventing the last entry from being used, causing the function to error out on the last level of the cache on Intel Raptorlake. Change the check to allow the entire array to be used.
Because the sysdetect component is designed to assume homogeneous cores, heterogeneous CPUs like Intel Raptorlake can have the total number of available threads be overestimated. The worst impact of this is an infinite loop in get_thread_affinity() of linux_cpu_utils.c. Fix infinite loop by adding a check to ensure /sys/ entry exists for the target thread.
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Pull Request Description
This PR fixes #256 by allowing the problem function to exit. However, this PR does not add support for heterogeneous CPU detection to
sysdetectand is more of a quick fix to ensure./utils/papi_hardware_availand thesysdetecttests fail. Additionally, while working on this I noticed that on Intel Raptorlakecpu_get_cache_info()fails to get information for the 4th cache level because the check to ensure no writes are made off the end of the cache level array is too strict. This PR allows the entire array to be used.Author Checklist
Why this PR exists. Reference all relevant information, including background, issues, test failures, etc
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The PR needs to pass all the tests