test/intel: Timestamp intervals

Make sure timestamp intervals are not too short by introducing another
test which compares them one after another.
Signed-off-by: Antonio Caggiano <antonio.caggiano@collabora.com>

test/src/intel_test.cc

@@ -17,7 +17,7 @@
 
 namespace pps::gpu
 {
-std::optional<IntelDriver> init_concrete_driver()
+std::optional<IntelDriver> init_concrete_driver(uint64_t sampling_period_ns = 1000000)
 {
     auto drm_device_opt = DrmDevice::create(0);
     if (!drm_device_opt) {
@@ -30,7 +30,6 @@ std::optional<IntelDriver> init_concrete_driver()
     driver.init_perfcnt();
     driver.enable_all_counters();
 
-    constexpr uint64_t sampling_period_ns = 1000000;
     driver.enable_perfcnt(sampling_period_ns);
 
     return driver;
@@ -40,7 +39,8 @@ std::optional<IntelDriver> init_concrete_driver()
 /// CPU timestamps and that the timing order is correct and preserved
 TEST(Intel, GpuTimestamps)
 {
-    auto driver = init_concrete_driver();
+    constexpr uint64_t sampling_period_ns = 1000000;
+    auto driver = init_concrete_driver(sampling_period_ns);
     if (!driver) {
         GTEST_SKIP_("Failed to initialize concrete driver");
     }
@@ -68,6 +68,34 @@ TEST(Intel, GpuTimestamps)
     }
 }
 
+TEST(Intel, TimestampIntervals)
+{
+    constexpr uint64_t sampling_period_ns = 1000000;
+    auto driver = init_concrete_driver(sampling_period_ns);
+    if (!driver) {
+        GTEST_SKIP_("Failed to initialize concrete driver");
+    }
+
+    uint64_t prev_cpu_ts = 0;
+    const uint32_t max_iterations = 32;
+    for (uint32_t iterations = 0; iterations < max_iterations; ++iterations) {
+        // Dump until we can read some records
+        while (!driver->dump_perfcnt()) { }
+
+        uint32_t sample_count = 0;
+        while (auto cpu_timestamp = driver->cpu_next()) {
+            if (iterations > 0) {
+                ASSERT_GT(cpu_timestamp - prev_cpu_ts, sampling_period_ns - 100000);
+            }
+
+            prev_cpu_ts = cpu_timestamp;
+            sample_count++;
+        }
+
+        EXPECT_GT(sample_count, 0);
+    }
+}
+
 /// @brief Make sure correlations timestamps are valid and that CPU timestamps
 /// calculated by the driver fall between first and last correlation
 TEST(Intel, Correlations)
@@ -94,34 +122,6 @@ TEST(Intel, Correlations)
     driver->disable_perfcnt();
 }
 
-std::vector<uint8_t> read_data_from_file(const char *path)
-{
-    auto file = std::fopen(path, "rb");
-    EXPECT_TRUE(file != nullptr);
-
-    std::fseek(file, 0, SEEK_END);
-    size_t file_size = std::ftell(file);
-    EXPECT_GT(file_size, 0);
-    std::fseek(file, 0, SEEK_SET);
-
-    std::vector<uint8_t> data = {};
-    data.resize(file_size);
-    size_t bytes_read = std::fread(data.data(), sizeof(data[0]), file_size, file);
-    EXPECT_EQ(bytes_read, file_size);
-
-    return data;
-}
-
-/// @brief Intel driver should be able to read perf records from data
-TEST(Intel, PerfCnt)
-{
-    // Dummy driver with no DRM device in it
-    auto driver = IntelDriver();
-    auto data = read_data_from_file("test/data/gpu/intel/intel.dump");
-    auto records = driver.parse_perf_records(data, data.size());
-    EXPECT_GT(records.size(), 0);
-}
-
 } // namespace pps::gpu
 
 int main(int argc, char **argv)