Extend Cpu_session with thread-affinity API

This patch introduces the functions 'affinity' and 'num_cpus' to the CPU
session interface. The interface extension will allow the assignment of
individual threads to CPUs. At this point, it is just a stub with no
actual platform support.

base-codezero/src/core/include/platform_thread.h

@@ -114,9 +114,9 @@ namespace Genode {
 			unsigned long pager_object_badge() const { return _tid; }
 
 			/**
-			 * Set the executing CPU for this thread.
+			 * Set the executing CPU for this thread
 			 */
-			void set_cpu(unsigned int cpu_no);
+			void affinity(unsigned cpu);
 
 			/**
 			 * Get thread name

base-codezero/src/core/platform_thread.cc

@@ -27,7 +27,7 @@ using namespace Genode;
 using namespace Codezero;
 
 
-void Platform_thread::set_cpu(unsigned int cpu_no)
+void Platform_thread::affinity(unsigned int cpu_no)
 {
 	PDBG("not yet implemented");
 }

base-fiasco/src/core/include/platform_thread.h

@@ -111,6 +111,13 @@ namespace Genode {
 			 */
 			int state(Genode::Thread_state *state_dst);
 
+			/**
+			 * Set the executing CPU for this thread
+			 *
+			 * SMP is not supported on L4/Fiasco.
+			 */
+			void affinity(unsigned) { }
+
 
 			/************************
 			 ** Accessor functions **

base-foc/include/foc_cpu_session/client.h

@@ -67,6 +67,15 @@ namespace Genode {
 		void exception_handler(Thread_capability thread, Signal_context_capability handler) {
 			call<Rpc_exception_handler>(thread, handler); }
 
+		void single_step(Thread_capability thread, bool enable) {
+			call<Rpc_single_step>(thread, enable); }
+
+		unsigned num_cpus() const {
+			return call<Rpc_num_cpus>(); }
+
+		void affinity(Thread_capability thread, unsigned cpu) {
+			call<Rpc_affinity>(thread, cpu); }
+
 		void enable_vcpu(Thread_capability cap, addr_t vcpu_state) {
 			call<Rpc_enable_vcpu>(cap, vcpu_state); }
 

base-foc/src/core/include/cpu_session_component.h

@@ -141,6 +141,8 @@ namespace Genode {
 			int name(Thread_capability, char *, size_t);
 			int state(Thread_capability, Thread_state *);
 			void exception_handler(Thread_capability, Signal_context_capability);
+			unsigned num_cpus() const;
+			void affinity(Thread_capability, unsigned);
 
 
 			/***********************************

base-foc/src/core/include/platform_thread.h

@@ -124,6 +124,11 @@ namespace Genode {
 			 */
 			int state(Genode::Thread_state *state_dst);
 
+			/**
+			 * Set the executing CPU for this thread
+			 */
+			void affinity(unsigned cpu);
+
 
 			/************************
 			 ** Accessor functions **

base-foc/src/core/platform_thread.cc

@@ -180,6 +180,11 @@ void Platform_thread::cancel_blocking()
 }
 
 
+void Platform_thread::affinity(unsigned cpu)
+{
+}
+
+
 void Platform_thread::_create_thread()
 {
 	l4_msgtag_t tag = l4_factory_create_thread(L4_BASE_FACTORY_CAP,

base-host/src/core/include/platform_thread.h

@@ -92,9 +92,9 @@ namespace Genode {
 			unsigned long pager_object_badge() const;
 
 			/**
-			 * Set the executing CPU for this thread.
+			 * Set the executing CPU for this thread
 			 */
-			void set_cpu(unsigned int cpu_no);
+			void affinity(unsigned cpu);
 
 			/**
 			 * Get thread name

base-host/src/core/platform_thread.cc

@@ -20,7 +20,7 @@
 using namespace Genode;
 
 
-void Platform_thread::set_cpu(unsigned int cpu_no)
+void Platform_thread::affinity(unsigned int cpu_no)
 {
 	PERR("not yet implemented");
 }

base-hw/src/core/include/platform_thread.h

@@ -139,9 +139,9 @@ namespace Genode {
 			unsigned long pager_object_badge() { return _id; }
 
 			/**
-			 * Set the executing CPU for this thread.
+			 * Set the executing CPU for this thread
 			 */
-			void set_cpu(unsigned int cpu_no)
+			void affinity(unsigned cpu)
 			{
 				kernel_log() << __PRETTY_FUNCTION__ << ": Not implemented\n";
 				while (1) ;

base-linux/src/core/include/platform_thread.h

@@ -59,6 +59,7 @@ namespace Genode {
 			int           start(void *ip, void *sp) { return 0; }
 			int           state(Thread_state *state_dst) { return 0; }
 			const char   *name() { return _name; }
+			void          affinity(unsigned) { }
 	};
 }
 

base-mb/src/core/include/platform_thread.h

@@ -141,9 +141,9 @@ namespace Genode {
 		inline unsigned long pager_object_badge() const { return _tid; }
 
 		/**
-		 * Set the executing CPU for this thread.
+		 * Set the executing CPU for this thread
 		 */
-		void set_cpu(unsigned int cpu_no = 0);
+		void affinity(unsigned cpu);
 
 		/**
 		 * Get thread name

base-mb/src/core/platform_thread.cc

@@ -81,7 +81,7 @@ Kernel::Utcb* Genode::physical_utcb(Native_thread_id tid)
 }
 
 
-void Platform_thread::set_cpu(unsigned int cpu_no) { PERR("not implemented"); }
+void Platform_thread::affinity(unsigned int cpu_no) { PERR("not implemented"); }
 
 
 void Platform_thread::cancel_blocking() { PERR("not implemented"); }

base-nova/include/cpu_session/client.h

@@ -80,6 +80,12 @@ namespace Genode {
 		Native_capability native_cap(Thread_capability cap) {
 			return call<Rpc_native_cap>(cap); }
 
+		unsigned num_cpus() const {
+			return call<Rpc_num_cpus>(); }
+
+		void affinity(Thread_capability thread, unsigned cpu) {
+			call<Rpc_affinity>(thread, cpu); }
+
 		private:
 
 		Native_capability pause_sync(Thread_capability target) {

base-nova/src/core/include/cpu_session_component.h

@@ -142,6 +142,8 @@ namespace Genode {
 			int name(Thread_capability, char *, size_t);
 			int state(Thread_capability, Thread_state *);
 			void exception_handler(Thread_capability, Signal_context_capability);
+			unsigned num_cpus() const;
+			void affinity(Thread_capability, unsigned);
 
 
 			/***********************************

base-nova/src/core/include/platform_thread.h

@@ -114,9 +114,9 @@ namespace Genode {
 			unsigned long pager_object_badge() const;
 
 			/**
-			 * Set the executing CPU for this thread.
+			 * Set the executing CPU for this thread
 			 */
-			void set_cpu(unsigned int cpu_no);
+			void affinity(unsigned cpu);
 
 			/**
 			 * Get thread name

base-nova/src/core/platform_thread.cc

@@ -35,7 +35,7 @@ using namespace Genode;
  ** Platform thread **
  *********************/
 
-void Platform_thread::set_cpu(unsigned int cpu_no)
+void Platform_thread::affinity(unsigned int cpu_no)
 {
 	PERR("not yet implemented");
 }

base-okl4/src/core/include/platform_thread.h

@@ -130,9 +130,9 @@ namespace Genode {
 			unsigned long pager_object_badge() const;
 
 			/**
-			 * Set the executing CPU for this thread.
+			 * Set the executing CPU for this thread
 			 */
-			void set_cpu(unsigned int cpu_no);
+			void affinity(unsigned cpu);
 
 
 			/*****************************

base-okl4/src/core/platform_thread.cc

@@ -36,7 +36,7 @@ using namespace Genode;
 using namespace Okl4;
 
 
-void Platform_thread::set_cpu(unsigned int cpu_no)
+void Platform_thread::affinity(unsigned int cpu_no)
 {
 	PERR("not yet implemented");
 }

base-pistachio/src/core/include/platform_thread.h

@@ -130,9 +130,9 @@ namespace Genode {
 				return convert_native_thread_id_to_badge(_l4_thread_id); }
 
 			/**
-			 * Set the executing CPU for this thread.
+			 * Set the executing CPU for this thread
 			 */
-			void set_cpu(unsigned int cpu_no);
+			void affinity(unsigned cpu);
 
 
 			/**********************************

base-pistachio/src/core/platform_thread.cc

@@ -39,7 +39,7 @@ static const bool verbose2 = true;
 #define PT_DBG(args...) if (verbose) PDBG(args); else {}
 
 
-void Platform_thread::set_cpu(unsigned int cpu_no)
+void Platform_thread::affinity(unsigned int cpu_no)
 {
 	if (cpu_no >= L4_NumProcessors(get_kip())) {
 		PERR("Invalid processor number.");
@@ -98,7 +98,7 @@ int Platform_thread::start(void *ip, void *sp, unsigned int cpu_no)
 	}
 
 	/* get the thread running on the right cpu */
-	set_cpu(cpu_no);
+	affinity(cpu_no);
 
 	/* assign priority */
 	if (!L4_Set_Priority(thread,

base/include/cpu_session/client.h

@@ -62,6 +62,12 @@ namespace Genode {
 
 		void single_step(Thread_capability thread, bool enable) {
 			call<Rpc_single_step>(thread, enable); }
+
+		unsigned num_cpus() const {
+			return call<Rpc_num_cpus>(); }
+
+		void affinity(Thread_capability thread, unsigned cpu) {
+			call<Rpc_affinity>(thread, cpu); }
 	};
 }
 

base/include/cpu_session/cpu_session.h

@@ -161,6 +161,19 @@ namespace Genode {
 			 */
 			virtual void single_step(Thread_capability thread, bool enable) {}
 
+			/**
+			 * Return number of CPUs available via the CPU session
+			 */
+			virtual unsigned num_cpus() const = 0;
+
+			/**
+			 * Assign thread to a CPU
+			 *
+			 * The 'cpu' argument is a CPU index starting at 0. It must be
+			 * smaller than the value returned by 'num_cpus()'.
+			 */
+			virtual void affinity(Thread_capability thread, unsigned cpu) = 0;
+
 			/**
 			 * Translate generic priority value to kernel-specific priority levels
 			 *
@@ -211,6 +224,8 @@ namespace Genode {
 			GENODE_RPC(Rpc_exception_handler, void, exception_handler,
 			                                  Thread_capability, Signal_context_capability);
 			GENODE_RPC(Rpc_single_step, void, single_step, Thread_capability, bool);
+			GENODE_RPC(Rpc_num_cpus, unsigned, num_cpus);
+			GENODE_RPC(Rpc_affinity, void, affinity, Thread_capability, unsigned);
 
 			/*
 			 * 'GENODE_RPC_INTERFACE' declaration done manually
@@ -233,8 +248,10 @@ namespace Genode {
 			        Meta::Type_tuple<Rpc_state,
 			        Meta::Type_tuple<Rpc_exception_handler,
 			        Meta::Type_tuple<Rpc_single_step,
+			        Meta::Type_tuple<Rpc_num_cpus,
+			        Meta::Type_tuple<Rpc_affinity,
 			                         Meta::Empty>
-			        > > > > > > > > > > > > Rpc_functions;
+			        > > > > > > > > > > > > > > Rpc_functions;
 	};
 }
 

base/src/core/cpu_session_component.cc

@@ -17,9 +17,10 @@
 #include <base/printf.h>
 #include <util/arg_string.h>
 
-/* Core includes */
+/* core includes */
 #include <cpu_session_component.h>
 #include <rm_session_component.h>
+#include <platform_generic.h>
 
 using namespace Genode;
 
@@ -162,6 +163,21 @@ void Cpu_session_component::exception_handler(Thread_capability         thread_c
 }
 
 
+unsigned Cpu_session_component::num_cpus() const
+{
+	return platform()->num_cpus();
+}
+
+
+void Cpu_session_component::affinity(Thread_capability thread_cap, unsigned cpu)
+{
+	Cpu_thread_component *thread = _lookup_thread(thread_cap);
+	if (!thread) return;
+
+	thread->platform_thread()->affinity(cpu);
+}
+
+
 Cpu_session_component::Cpu_session_component(Rpc_entrypoint *thread_ep,
                                              Pager_entrypoint *pager_ep,
                                              Allocator *md_alloc,

base/src/core/include/cpu_session_component.h

@@ -134,6 +134,8 @@ namespace Genode {
 			int name(Thread_capability, char *, size_t);
 			int state(Thread_capability, Thread_state *);
 			void exception_handler(Thread_capability, Signal_context_capability);
+			unsigned num_cpus() const;
+			void affinity(Thread_capability, unsigned);
 	};
 }
 

base/src/core/include/platform_generic.h

@@ -88,6 +88,11 @@ namespace Genode {
 			 * Return true if platform supports direct unmap (no mapping db)
 			 */
 			virtual bool supports_direct_unmap() const { return false; }
+
+			/**
+			 * Return number of physical CPUs present in the platform
+			 */
+			virtual unsigned num_cpus() const { return 1; }
 	};
 
 

ports/src/app/gdb_monitor/cpu_session_component.cc

@@ -185,6 +185,18 @@ void Cpu_session_component::single_step(Thread_capability thread_cap, bool enabl
 }
 
 
+unsigned Cpu_session_component::num_cpus() const
+{
+	return _parent_cpu_session.num_cpus();
+}
+
+
+void Cpu_session_component::affinity(Thread_capability thread_cap, unsigned cpu)
+{
+	_parent_cpu_session.affinity(thread_cap, cpu);
+}
+
+
 Cpu_session_component::Cpu_session_component(Signal_receiver *exception_signal_receiver, const char *args)
 : _parent_cpu_session(env()->parent()->session<Cpu_session>(args)),
   _exception_signal_receiver(exception_signal_receiver)

ports/src/app/gdb_monitor/cpu_session_component.h

@@ -69,6 +69,8 @@ class Cpu_session_component : public Rpc_object<Cpu_session>
 		void exception_handler(Thread_capability         thread,
 		                       Signal_context_capability handler);
 		void single_step(Thread_capability thread, bool enable);
+		unsigned num_cpus() const;
+		void affinity(Thread_capability, unsigned);
 };
 
 #endif /* _CPU_SESSION_COMPONENT_H_ */

ports/src/noux/cpu_session_component.h

@@ -131,6 +131,11 @@ namespace Noux {
 			void single_step(Thread_capability thread, bool enable) {
 				_cpu.single_step(thread, enable); }
 
+			unsigned num_cpus() const {
+				return _cpu.num_cpus(); }
+
+			void affinity(Thread_capability thread, unsigned cpu) {
+				_cpu.affinity(thread, cpu); }
 	};
 }