diff --git a/libs/ardour/export_graph_builder.cc b/libs/ardour/export_graph_builder.cc
index 7b98725aa3..545e1207ac 100644
--- a/libs/ardour/export_graph_builder.cc
+++ b/libs/ardour/export_graph_builder.cc
@@ -157,7 +157,7 @@ namespace ARDOUR {
 
 ExportGraphBuilder::ExportGraphBuilder (Session const & session)
 	: session (session)
-	, thread_pool (hardware_concurrency())
+	, thread_pool (PBD::hardware_concurrency())
 {
 	process_buffer_samples = session.engine().samples_per_cycle();
 }
diff --git a/libs/ardour/globals.cc b/libs/ardour/globals.cc
index 3f5cff7ccb..8ffb70fae6 100644
--- a/libs/ardour/globals.cc
+++ b/libs/ardour/globals.cc
@@ -749,7 +749,7 @@ ARDOUR::init (bool try_optimization, const char* localedir, bool with_gui)
 	 * WaveViewThreads::start_threads adds `min (8, hw - 1)`
 	 *
 	 */
-	BufferManager::init (hardware_concurrency () * 3 + 6);
+	BufferManager::init (PBD::hardware_concurrency () * 3 + 6);
 
 	PannerManager::instance ().discover_panners ();
 
diff --git a/libs/ardour/io_tasklist.cc b/libs/ardour/io_tasklist.cc
index d1756fe1fd..7724a67947 100644
--- a/libs/ardour/io_tasklist.cc
+++ b/libs/ardour/io_tasklist.cc
@@ -45,7 +45,7 @@ IOTaskList::IOTaskList (uint32_t n_threads)
 	, _exec_sem ("io thread exec", 0)
 	, _idle_sem ("io thread idle", 0)
 {
-	assert (n_threads <= hardware_concurrency ());
+	assert (n_threads <= PBD::hardware_concurrency ());
 
 	if (n_threads < 2) {
 		return;
diff --git a/libs/ardour/luabindings.cc b/libs/ardour/luabindings.cc
index 683ddeee97..a0746b970b 100644
--- a/libs/ardour/luabindings.cc
+++ b/libs/ardour/luabindings.cc
@@ -610,8 +610,8 @@ LuaBindings::common (lua_State* L)
 		.addConst ("UseGroup", PBD::Controllable::GroupControlDisposition(PBD::Controllable::UseGroup))
 		.endNamespace ()
 
-		.addFunction ("hardware_concurrency", hardware_concurrency)
-		.addFunction ("max_mmcss_threads_per_process", max_mmcss_threads_per_process)
+		.addFunction ("hardware_concurrency", PBD::hardware_concurrency)
+		.addFunction ("max_mmcss_threads_per_process", PBD::max_mmcss_threads_per_process)
 
 		.endNamespace (); // PBD
 
diff --git a/libs/ardour/utils.cc b/libs/ardour/utils.cc
index cacb5f79db..345c288c0e 100644
--- a/libs/ardour/utils.cc
+++ b/libs/ardour/utils.cc
@@ -718,7 +718,7 @@ ARDOUR::how_many_dsp_threads ()
 {
         /* CALLER MUST HOLD PROCESS LOCK */
 
-        int num_cpu = hardware_concurrency();
+        int num_cpu = PBD::hardware_concurrency();
         int pu = Config->get_processor_usage ();
         uint32_t num_threads = max (num_cpu - 1, 2); // default to number of cpus minus one, or 2, whichever is larger
 
@@ -750,7 +750,7 @@ ARDOUR::how_many_dsp_threads ()
 uint32_t
 ARDOUR::how_many_io_threads ()
 {
-	int num_cpu = hardware_concurrency();
+	int num_cpu = PBD::hardware_concurrency();
 	int pu = Config->get_io_thread_count ();
 	uint32_t num_threads = max (num_cpu - 2, 2);
 	if (pu < 0) {
diff --git a/libs/pbd/cpus.cc b/libs/pbd/cpus.cc
index 6df37441b8..f39c8a57de 100644
--- a/libs/pbd/cpus.cc
+++ b/libs/pbd/cpus.cc
@@ -40,7 +40,7 @@
 #endif
 
 int32_t
-max_mmcss_threads_per_process ()
+PBD::max_mmcss_threads_per_process ()
 {
 #ifdef PLATFORM_WINDOWS
 	DWORD dwType = REG_DWORD;
@@ -61,7 +61,7 @@ max_mmcss_threads_per_process ()
 }
 
 uint32_t
-hardware_concurrency()
+PBD::hardware_concurrency()
 {
 	if (getenv("ARDOUR_CONCURRENCY")) {
 		int c = atoi (getenv("ARDOUR_CONCURRENCY"));
diff --git a/libs/pbd/pbd/cpus.h b/libs/pbd/pbd/cpus.h
index e33aee4d3d..eb52a01c1f 100644
--- a/libs/pbd/pbd/cpus.h
+++ b/libs/pbd/pbd/cpus.h
@@ -22,5 +22,9 @@
 
 #include "pbd/libpbd_visibility.h"
 
+namespace PBD{
+
 LIBPBD_API extern uint32_t hardware_concurrency ();
 LIBPBD_API extern int32_t max_mmcss_threads_per_process ();
+
+}
diff --git a/libs/waveview/wave_view_private.cc b/libs/waveview/wave_view_private.cc
index eb68bfbfe5..7dc681d327 100644
--- a/libs/waveview/wave_view_private.cc
+++ b/libs/waveview/wave_view_private.cc
@@ -342,7 +342,7 @@ WaveViewThreads::start_threads ()
 {
 	assert (!_threads.size());
 
-	const int num_cpus = hardware_concurrency ();
+	const int num_cpus = PBD::hardware_concurrency ();
 
 	/* the upper limit of 8 here is entirely arbitrary. It just doesn't
 	 * seem worthwhile having "ncpus" of low priority threads for