spec: Test CPU performance

Measure the runtime of 1000 no-operation instructions.  This may help to
investigate runtime measurement variations which do not result from code
generation or source code changes.

The runtime measurement of a function which does nothing and just
returns gives an estimate of the measurement overhead.

4 files changed, 134 insertions, 0 deletions

diff --git a/spec/score/cpu/req/perf-empty.yml b/spec/score/cpu/req/perf-empty.yml
new file mode 100644
index 00000000..d8707edf
--- /dev/null
+++ b/spec/score/cpu/req/perf-empty.yml
@@ -0,0 +1,37 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 2023 embedded brains GmbH & Co. KG
+enabled-by: true
+links:
+- role: requirement-refinement
+  uid: perf-runtime
+- role: runtime-measurement-request
+  uid: ../val/perf
+non-functional-type: performance-runtime
+params: {}
+rationale: |
+  The runtime measurement of a function which does nothing and just returns
+  gives an estimate of the measurement overhead.
+references: []
+requirement-type: non-functional
+test-body:
+  brief: |
+    Do nothing and just return.
+  code: |
+    /* No code */
+  description: null
+test-cleanup: null
+test-prepare: null
+test-setup: null
+test-teardown:
+  brief: |
+    Discard samples interrupted by a clock tick.
+  code: |
+    return tic == toc;
+  description: null
+text: |
+  While the execution environment is ${.:/environment}, while the measurement
+  sample is a function which just returns and does nothing else, when exactly
+  ${../val/perf:/params/sample-count} samples are collected, the
+  ${.:/limit-kind} shall be ${.:/limit-condition}.
+type: requirement
diff --git a/spec/score/cpu/req/perf-nops.yml b/spec/score/cpu/req/perf-nops.yml
new file mode 100644
index 00000000..8cecf5e2
--- /dev/null
+++ b/spec/score/cpu/req/perf-nops.yml
@@ -0,0 +1,55 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 2023 embedded brains GmbH & Co. KG
+enabled-by: true
+links:
+- role: requirement-refinement
+  uid: perf-runtime
+- role: runtime-measurement-request
+  uid: ../val/perf
+non-functional-type: performance-runtime
+params: {}
+rationale: |
+  The runtime measurement of a fixed number of no-operation instructions may
+  help to investigate runtime measurement variations which do not result from
+  code generation or source code changes.
+references: []
+requirement-type: non-functional
+test-body:
+  brief: |
+    Execute exactly 1000 no-operation instructions.
+  code: |
+    #define NOPS_10 \
+      _CPU_Instruction_no_operation(); _CPU_Instruction_no_operation(); \
+      _CPU_Instruction_no_operation(); _CPU_Instruction_no_operation(); \
+      _CPU_Instruction_no_operation(); _CPU_Instruction_no_operation(); \
+      _CPU_Instruction_no_operation(); _CPU_Instruction_no_operation(); \
+      _CPU_Instruction_no_operation(); _CPU_Instruction_no_operation();
+    #define NOPS_100 NOPS_10 NOPS_10 NOPS_10 NOPS_10 NOPS_10 NOPS_10 NOPS_10 \
+      NOPS_10 NOPS_10 NOPS_10
+    NOPS_100
+    NOPS_100
+    NOPS_100
+    NOPS_100
+    NOPS_100
+    NOPS_100
+    NOPS_100
+    NOPS_100
+    NOPS_100
+    NOPS_100
+  description: null
+test-cleanup: null
+test-prepare: null
+test-setup: null
+test-teardown:
+  brief: |
+    Discard samples interrupted by a clock tick.
+  code: |
+    return tic == toc;
+  description: null
+text: |
+  While the execution environment is ${.:/environment}, while the measurement
+  sample is the runtime of exactly 1000 no-operation instructions, when exactly
+  ${../val/perf:/params/sample-count} samples are collected, the
+  ${.:/limit-kind} shall be ${.:/limit-condition}.
+type: requirement
diff --git a/spec/score/cpu/req/perf-runtime.yml b/spec/score/cpu/req/perf-runtime.yml
new file mode 100644
index 00000000..7046881a
--- /dev/null
+++ b/spec/score/cpu/req/perf-runtime.yml
@@ -0,0 +1,16 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 2023 embedded brains GmbH & Co. KG
+enabled-by: true
+links:
+- role: requirement-refinement
+  uid: /req/perf-runtime
+- role: requirement-refinement
+  uid: ../if/group
+non-functional-type: performance
+rationale: null
+references: []
+requirement-type: non-functional
+text: |
+  The runtime of CPU port interfaces shall be measured.
+type: requirement
diff --git a/spec/score/cpu/val/perf.yml b/spec/score/cpu/val/perf.yml
new file mode 100644
index 00000000..c42f0b0f
--- /dev/null
+++ b/spec/score/cpu/val/perf.yml
@@ -0,0 +1,26 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 2023 embedded brains GmbH & Co. KG
+enabled-by: true
+links:
+- role: validation
+  uid: /req/perf-runtime
+params:
+  sample-count: 100
+test-brief: |
+  This test case provides a context to run CPU port performance tests.
+test-cleanup: null
+test-context: []
+test-context-support: null
+test-description: null
+test-includes:
+- rtems/score/cpuimpl.h
+test-local-includes:
+- tx-support.h
+test-prepare: null
+test-setup: null
+test-stop: null
+test-support: null
+test-target: testsuites/validation/tc-cpu-performance.c
+test-teardown: null
+type: runtime-measurement-test