pipeline: create shader-store pipelines at boot on half the hardware threads

src/common/parallelFor.h

@@ -0,0 +1,35 @@
+#ifndef KYTY_COMMON_PARALLELFOR_H_
+#define KYTY_COMMON_PARALLELFOR_H_
+
+#include <algorithm>
+#include <atomic>
+#include <cstddef>
+#include <thread>
+#include <vector>
+
+namespace Common {
+
+// Half the hardware threads, at least one.
+inline size_t ParallelThreads() {
+	return std::max(1u, std::thread::hardware_concurrency() / 2);
+}
+
+// Calls job(i) for every i below count on up to ParallelThreads() threads, the caller included.
+template <typename Job>
+void ParallelFor(size_t count, const Job& job) {
+	std::atomic_size_t next = 0;
+	const auto         work = [&] {
+		for (auto i = next++; i < count; i = next++) {
+			job(i);
+		}
+	};
+	std::vector<std::jthread> helpers;
+	for (auto i = std::min(count, ParallelThreads()); i > 1; i--) {
+		helpers.emplace_back(work);
+	}
+	work();
+}
+
+} // namespace Common
+
+#endif // KYTY_COMMON_PARALLELFOR_H_