[PATCH 0/7] Core sharing validation for CPU isolation

[John Kacur <jkacur@redhat.com>]

This patch series adds validation to detect and warn when CPUs sharing
physical cores (SMT siblings) are assigned to different workload types,
which can defeat CPU isolation and corrupt real-time measurements.

When SMT/hyperthreading is enabled, CPUs sharing a physical core also
share L1/L2 caches, execution units, TLB, and other core-level resources.
Running different workload types (housekeeping, measurement, load) on
sibling threads defeats CPU isolation and can create unreproducible
results.

The series implements:

1. CoreSiblings class - Provides a simple interface for querying which
   CPUs share physical cores by reading thread_siblings_list from sysfs.
   Works with any SMT configuration (1-way, 2-way, 4-way, 8-way).

2. Core sharing validation - Detects when isolated CPUs share cores
   between housekeeping, measurement, and load groups. Warnings are
   logged to console and included in XML reports.

3. XSLT integration - Warnings appear in text reports generated with
   the -Z option via a CoreSharingWarnings section.

4. Optional stricter validation - --warn-non-isolated-core-sharing
   flag enables warnings for measurement vs load CPU pairs even when
   neither is isolated, for users who want maximum isolation assurance.

The validation is purely informational - it warns users but does not
prevent execution, allowing informed decisions about CPU configurations.

Testing includes comprehensive scenarios with both isolated and
non-isolated CPU configurations, verified with real isolated CPUs.

John Kacur (7):
  rteval: Add CoreSiblings class for CPU core topology queries
  rteval: Add core sharing validation for CPU isolation
  rteval: Include core sharing warnings in XML report
  rteval: Add temporary test for core sharing validation with mocked
    isolated CPUs
  rteval: Display core sharing warnings in text report
  rteval: Add --warn-non-isolated-core-sharing option for measurement vs
    load warnings
  rteval: Include --warn-non-isolated-core-sharing warnings in XML
    report

 rteval-cmd                     |  18 +++-
 rteval/rteval_text.xsl         |  13 ++-
 rteval/sysinfo/__init__.py     |   3 +
 rteval/sysinfo/coresiblings.py | 116 +++++++++++++++++++++++++
 rteval/sysinfo/cputopology.py  |  35 ++++++++
 rteval/systopology.py          |  64 ++++++++++++++
 test_full_validation.py        | 151 +++++++++++++++++++++++++++++++++
 7 files changed, 398 insertions(+), 2 deletions(-)
 create mode 100644 rteval/sysinfo/coresiblings.py
 create mode 100644 test_full_validation.py

-- 
2.53.0