profile multicore mechanism state and current calls individually (#492)

The built in profiler generates timings for state and current for individual multicore mechanisms.

Modcc generates and PE(advance_integrate_{state,current}_X) profiler calls (along with corresponding PL() for calls to multicore mechanism nrn_state and nrn_current API calls.

No timings are made for the gpu back end, which is not properly supported by the current profiling tools.

modcc/printer/cprinter.cpp

@@ -14,6 +14,13 @@ using io::indent;
 using io::popindent;
 using io::quote;
 
+constexpr bool with_profiling() {
+#ifdef ARB_HAVE_PROFILING
+    return true;
+#else
+    return false;
+#endif
+}
 
 void emit_procedure_proto(std::ostream&, ProcedureExpression*, const std::string& qualified = "");
 void emit_simd_procedure_proto(std::ostream&, ProcedureExpression*, const std::string& qualified = "");
@@ -106,6 +113,9 @@ std::string emit_cpp_source(const Module& module_, const std::string& ns, simd_s
         "#include <" << arb_header_prefix() << "backends/multicore/mechanism.hpp>\n"
         "#include <" << arb_header_prefix() << "math.hpp>\n";
 
+    with_profiling() &&
+        out << "#include <" << arb_header_prefix() << "profiling/profiler.hpp>\n";
+
     if (with_simd) {
         out << "#include <" << arb_header_prefix() << "simd/simd.hpp>\n";
     }
@@ -306,11 +316,15 @@ std::string emit_cpp_source(const Module& module_, const std::string& ns, simd_s
     out << popindent << "}\n\n";
 
     out << "void " << class_name << "::nrn_state() {\n" << indent;
+    with_profiling() && out << "PE(advance_integrate_state_" << name << ");\n";
     emit_body(state_api);
+    with_profiling() && out <<  "PL();\n";
     out << popindent << "}\n\n";
 
     out << "void " << class_name << "::nrn_current() {\n" << indent;
+    with_profiling() && out << "PE(advance_integrate_current_" << name << ");\n";
     emit_body(current_api);
+    with_profiling() && out <<  "PL();\n";
     out << popindent << "}\n\n";
 
     out << "void " << class_name << "::write_ions() {\n" << indent;

src/fvm_lowered_cell_impl.hpp

@@ -170,13 +170,13 @@ fvm_integration_result fvm_lowered_cell_impl<Backend>::integrate(
         state_->deliverable_events.mark_until_after(state_->time);
         PL();
 
-        PE(advance_integrate_current);
+        PE(advance_integrate_current_zero);
         state_->zero_currents();
+        PL();
         for (auto& m: mechanisms_) {
             m->deliver_events();
             m->nrn_current();
         }
-        PL();
 
         PE(advance_integrate_events);
         state_->deliverable_events.drop_marked_events();
@@ -208,11 +208,9 @@ fvm_integration_result fvm_lowered_cell_impl<Backend>::integrate(
 
         // Integrate mechanism state.
 
-        PE(advance_integrate_state);
         for (auto& m: mechanisms_) {
             m->nrn_state();
         }
-        PL();
 
         // Update ion concentrations.