Speed up benchmark cpu tests with _BORG_BENCHMARK_CPU_TEST env var

Add _BORG_BENCHMARK_CPU_TEST environment variable (following the existing
pattern of _BORG_BENCHMARK_CRUD_TEST) that reduces:
- timeit iterations from 100 to 1 (10 to 1 for compression)
- KDF iterations from 5 to 1
- random data buffer from 10MB to 100KB

Set this env var in test_benchmark_cpu and test_benchmark_cpu_json so
they complete quickly in CI while still exercising the full code path.

Fixes #9414

Signed-off-by: edvatar <88481784+toroleapinc@users.noreply.github.com>

src/borg/archiver/benchmark_cmd.py

@@ -167,7 +167,13 @@ class BenchmarkMixIn:
 
         result = {} if args.json else None
 
-        random_10M = os.urandom(10 * 1000 * 1000)
+        is_test = "_BORG_BENCHMARK_CPU_TEST" in os.environ
+        # Use minimal iterations and data size in test mode to keep CI fast.
+        number_default = 1 if is_test else 100
+        number_compression = 1 if is_test else 10
+        data_size = 100 * 1000 if is_test else 10 * 1000 * 1000
+
+        random_10M = os.urandom(data_size)
         key_256 = os.urandom(32)
         key_128 = os.urandom(16)
         key_96 = os.urandom(12)
@@ -202,7 +208,7 @@ class BenchmarkMixIn:
             ),
             ("fixed,1048576", "ch = get_chunker('fixed', 1048576, sparse=False)", "chunkit(ch)", locals()),
         ]:
-            dt = timeit(func, setup, number=100, globals=vars)
+            dt = timeit(func, setup, number=number_default, globals=vars)
             if args.json:
                 algo, _, algo_params = spec.partition(",")
                 result["chunkers"].append({"algo": algo, "algo_params": algo_params, "size": size, "time": dt})
@@ -218,7 +224,7 @@ class BenchmarkMixIn:
         size = 1000000000
         tests = [("xxh64", lambda: xxh64(random_10M)), ("crc32 (zlib)", lambda: crc32(random_10M))]
         for spec, func in tests:
-            dt = timeit(func, number=100)
+            dt = timeit(func, number=number_default)
             if args.json:
                 result["checksums"].append({"algo": spec, "size": size, "time": dt})
             else:
@@ -235,7 +241,7 @@ class BenchmarkMixIn:
             ("hmac-sha256", lambda: hmac_sha256(key_256, random_10M)),
             ("blake2b-256", lambda: blake2b_256(key_256, random_10M)),
         ]:
-            dt = timeit(func, number=100)
+            dt = timeit(func, number=number_default)
             if args.json:
                 result["hashes"].append({"algo": spec, "size": size, "time": dt})
             else:
@@ -275,7 +281,7 @@ class BenchmarkMixIn:
             ),
         ]
         for spec, func in tests:
-            dt = timeit(func, number=100)
+            dt = timeit(func, number=number_default)
             if args.json:
                 result["encryption"].append({"algo": spec, "size": size, "time": dt})
             else:
@@ -285,7 +291,7 @@ class BenchmarkMixIn:
             print("KDFs (slow is GOOD, use argon2!) ===============================")
         else:
             result["kdf"] = []
-        count = 5
+        count = 1 if is_test else 5
         for spec, func in [
             ("pbkdf2", lambda: FlexiKey.pbkdf2("mypassphrase", b"salt" * 8, PBKDF2_ITERATIONS, 32)),
             ("argon2", lambda: FlexiKey.argon2("mypassphrase", 64, b"S" * ARGON2_SALT_BYTES, **ARGON2_ARGS)),
@@ -319,7 +325,7 @@ class BenchmarkMixIn:
         ]:
             compressor = CompressionSpec(spec).compressor
             size = 100000000
-            dt = timeit(lambda: compressor.compress({}, random_10M), number=10)
+            dt = timeit(lambda: compressor.compress({}, random_10M), number=number_compression)
             if args.json:
                 algo, _, algo_params = spec.partition(",")
                 result["compression"].append({"algo": algo, "algo_params": algo_params, "size": size, "time": dt})
@@ -334,7 +340,7 @@ class BenchmarkMixIn:
         items = [item.as_dict()] * 1000
         size = "100k Items"
         spec = "msgpack"
-        dt = timeit(lambda: msgpack.packb(items), number=100)
+        dt = timeit(lambda: msgpack.packb(items), number=number_default)
         if args.json:
             result["msgpack"].append({"algo": spec, "count": 100000, "time": dt})
         else:

src/borg/testsuite/archiver/benchmark_cmd_test.py

@@ -45,7 +45,8 @@ def test_benchmark_crud_json_lines(archiver, monkeypatch):
         assert entry["io"] > 0
 
 
-def test_benchmark_cpu(archiver):
+def test_benchmark_cpu(archiver, monkeypatch):
+    monkeypatch.setenv("_BORG_BENCHMARK_CPU_TEST", "YES")
     output = cmd(archiver, "benchmark", "cpu")
     # verify all section headers appear in the plain-text output
     assert "Chunkers" in output
@@ -57,7 +58,8 @@ def test_benchmark_cpu(archiver):
     assert "msgpack" in output
 
 
-def test_benchmark_cpu_json(archiver):
+def test_benchmark_cpu_json(archiver, monkeypatch):
+    monkeypatch.setenv("_BORG_BENCHMARK_CPU_TEST", "YES")
     output = cmd(archiver, "benchmark", "cpu", "--json")
     result = json.loads(output)
     assert isinstance(result, dict)