headers: call per-scrape native functions with SyscallN (#2746)

Signed-off-by: Jan-Otto Kröpke <mail@jkroepke.de>

internal/headers/psapi/psapi_test.go

@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: Apache-2.0
+//
+// Copyright The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build windows
+
+package psapi_test
+
+import (
+	"testing"
+
+	"github.com/prometheus-community/windows_exporter/internal/headers/psapi"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGetPerformanceInfo(t *testing.T) {
+	t.Parallel()
+
+	info, err := psapi.GetPerformanceInfo()
+	require.NoError(t, err)
+	require.NotZero(t, info.PageSize)
+}
+
+// TestGetPerformanceInfoDoesNotAllocate checks that the result struct, whose
+// address is passed to the native call, stays on the stack.
+func TestGetPerformanceInfoDoesNotAllocate(t *testing.T) {
+	allocs := testing.AllocsPerRun(100, func() {
+		_, _ = psapi.GetPerformanceInfo()
+	})
+
+	require.Zero(t, allocs)
+}
+
+func BenchmarkGetPerformanceInfo(b *testing.B) {
+	b.ReportAllocs()
+
+	for b.Loop() {
+		_, _ = psapi.GetPerformanceInfo()
+	}
+}