[PATCH v3 00/14] test: fix test failures on high cores

[Stephen Hemminger <stephen@networkplumber.org>]

This series addresses several categories of test infrastructure issues:

1. Spinloop synchronization fixes (patch 1)
   
   Tests using tight spinloops for thread synchronization cause sporadic
   failures on high core count AMD Zen systems. The loops starve SMT
   sibling threads and create race conditions. Adding rte_pause() to
   all synchronization spinloops fixes these issues.

2. Test scaling for high core count systems (patches 2-5)
   
   Several tests use fixed iteration counts that cause timeouts on
   systems with many cores due to increased lock contention. A new
   helper function test_scale_iterations() scales iterations inversely
   with core count to maintain roughly constant test duration.

   Affected tests:
   - atomic_autotest (Bugzilla #952)
   - mcslock_autotest  
   - stack_autotest
   - timer_secondary_autotest

3. BPF test fixes (patches 6-8, 14)
   
   - Fix missing error handling in ELF load tests
   - Fix clang 20+ compatibility by restricting to BPF v2 instruction
     set (Bugzilla #1844)
   - Skip ELF test gracefully if null PMD is disabled
   - Fix incorrect size parameter in Rx/Tx load tests

4. Parallel test execution fixes (patches 9-10)
   
   Multiple tests colliding on the default "rte" file-prefix causes EAL
   initialization failures when running tests in parallel. Restore unique
   file-prefix for all fast-tests on Linux, including a separate prefix
   for trace_autotest_with_traces.

5. Test skip conditions (patches 11-13)
   
   Tests that depend on optional drivers (null PMD, eventdev) should skip
   gracefully when those drivers are disabled via -Ddisable_drivers=
   rather than failing.

v4 - add additional scaling for failures reported on 96 core system
   - gracefully handle case where null PMD disabled in build

Stephen Hemminger (14):
  test: add pause to synchronization spinloops
  test: scale atomic test based on core count
  test/mcslock: scale test based on number of cores
  test/stack: scale test based on number of cores
  test/timer: scale test based on number of cores
  test/bpf: fix error handling in ELF load tests
  test/bpf: fix unsupported BPF instructions in ELF load test
  test/bpf: skip ELF test if null PMD disabled
  test: add file-prefix for all fast-tests on Linux
  test: fix trace_autotest_with_traces parallel execution
  test/eventdev: skip test if eventdev driver disabled
  test/pcapng: skip test if null driver missing
  test/vdev: skip test if no null PMD
  test/bpf: pass correct size for Rx/Tx load tests

 app/test/bpf/meson.build             |  3 +-
 app/test/meson.build                 |  4 +-
 app/test/suites/meson.build          | 19 +++++---
 app/test/test.h                      | 19 ++++++++
 app/test/test_atomic.c               | 66 ++++++++++++++++------------
 app/test/test_bpf.c                  | 13 ++++--
 app/test/test_event_eth_tx_adapter.c | 11 +++--
 app/test/test_mcslock.c              | 10 +++--
 app/test/test_stack.c                |  8 ++--
 app/test/test_threads.c              | 17 +++----
 app/test/test_timer_secondary.c      | 14 +++---
 11 files changed, 121 insertions(+), 63 deletions(-)

-- 
2.51.0