Add DPCP and DFLP linear program generation

These files implement the generation and evaluation of linear programs
that bound maximum s-aware pi-blocking under the DPCP and the DFLP.

1 files changed, 177 insertions, 0 deletions

diff --git a/native/src/blocking/linprog/lp_common.cpp b/native/src/blocking/linprog/lp_common.cpp
new file mode 100644
index 0000000..808ff28
--- /dev/null
+++ b/native/src/blocking/linprog/lp_common.cpp
@@ -0,0 +1,177 @@
+#include "lp_common.h"
+
+// LP-based analysis of semaphore protocols.
+// Based on the paper:
+// B. Brandenburg, "Improved Analysis and Evaluation of Real-Time Semaphore
+// Protocols for P-FP Scheduling", Proceedings of the 19th IEEE Real-Time and
+// Embedded Technology and Applications Symposium (RTAS 2013), April 2013.
+
+void set_blocking_objective(
+        VarMapper& vars,
+        const ResourceSharingInfo& info, const ResourceLocality& locality,
+        const TaskInfo& ti,
+        LinearProgram& lp,
+        LinearExpression *local_obj,
+        LinearExpression *remote_obj)
+{
+        LinearExpression *obj;
+
+        obj = lp.get_objective();
+
+        foreach_task_except(info.get_tasks(), ti, tx)
+        {
+                unsigned int t = tx->get_id();
+                foreach(tx->get_requests(), request)
+                {
+                        unsigned int q = request->get_resource_id();
+                        bool local = locality[q] == (int) ti.get_cluster();
+                        double length;
+
+                        // Sanity check topology info in debug mode.
+                        assert(locality[q] != NO_CPU);
+
+                        length = request->get_request_length();
+
+                        foreach_request_instance(*request, ti, v)
+                        {
+                                unsigned int var_id;
+
+                                var_id = vars.lookup(t, q, v, BLOCKING_DIRECT);
+                                obj->add_term(length, var_id);
+                                if (local && local_obj)
+                                        local_obj->add_term(length, var_id);
+                                else if (!local && remote_obj)
+                                        remote_obj->add_term(length, var_id);
+
+                                var_id = vars.lookup(t, q, v, BLOCKING_INDIRECT);
+                                obj->add_term(length, var_id);
+                                if (local && local_obj)
+                                        local_obj->add_term(length, var_id);
+                                else if (!local && remote_obj)
+                                        remote_obj->add_term(length, var_id);
+
+                                var_id = vars.lookup(t, q, v, BLOCKING_PREEMPT);
+                                obj->add_term(length, var_id);
+                                if (local && local_obj)
+                                        local_obj->add_term(length, var_id);
+                                else if (!local && remote_obj)
+                                        remote_obj->add_term(length, var_id);
+                        }
+                }
+        }
+}
+
+// Constraint 1 in [Brandenburg 2013]
+void add_mutex_constraints(
+        VarMapper& vars,
+        const ResourceSharingInfo& info,
+        const TaskInfo& ti,
+        LinearProgram& lp)
+{
+
+        foreach_task_except(info.get_tasks(), ti, tx)
+        {
+                unsigned int t = tx->get_id();
+                foreach(tx->get_requests(), request)
+                {
+                        unsigned int q = request->get_resource_id();
+                        foreach_request_instance(*request, ti, v)
+                        {
+                                LinearExpression *exp = new LinearExpression();
+                                unsigned int var_id;
+
+                                var_id = vars.lookup(t, q, v, BLOCKING_DIRECT);
+                                exp->add_var(var_id);
+
+                                var_id = vars.lookup(t, q, v, BLOCKING_INDIRECT);
+                                exp->add_var(var_id);
+
+                                var_id = vars.lookup(t, q, v, BLOCKING_PREEMPT);
+                                exp->add_var(var_id);
+
+                                lp.add_inequality(exp, 1);
+                        }
+                }
+        }
+}
+
+// Constraint 2 in [Brandenburg 2013]
+void add_topology_constraints(
+        VarMapper& vars,
+        const ResourceSharingInfo& info,
+        const ResourceLocality& locality,
+        const TaskInfo& ti,
+        LinearProgram& lp)
+{
+        LinearExpression *exp = new LinearExpression();
+
+        foreach_task_except(info.get_tasks(), ti, tx)
+        {
+                unsigned int t = tx->get_id();
+                foreach_remote_request(tx->get_requests(), locality, ti, request)
+                {
+                        unsigned int q = request->get_resource_id();
+                        foreach_request_instance(*request, ti, v)
+                        {
+                                unsigned int var_id;
+                                var_id = vars.lookup(t, q, v, BLOCKING_PREEMPT);
+                                exp->add_var(var_id);
+                        }
+                }
+        }
+        lp.add_equality(exp, 0);
+}
+
+static unsigned int max_num_arrivals_remote(
+        const ResourceLocality& locality,
+        const TaskInfo& ti)
+{
+        // initialize to 1 to account for job release
+        unsigned int count = 1;
+
+        // count how often resources on remote cores are accessed
+        foreach(ti.get_requests(), req)
+                if (locality[req->get_resource_id()] != (int) ti.get_cluster())
+                        count += req->get_num_requests();
+
+        return count;
+}
+
+
+// Constraint 3 in [Brandenburg 2013]
+// One priority-boosting-related preemption per local task
+// each time that Ji arrives (is released or resumed)
+void add_local_lower_priority_constraints(
+        VarMapper& vars,
+        const ResourceSharingInfo& info,
+        const ResourceLocality& locality,
+        const TaskInfo& ti,
+        LinearProgram& lp)
+{
+        unsigned int num_arrivals = max_num_arrivals_remote(locality, ti);
+
+        foreach_local_lowereq_priority_task_except(info.get_tasks(), ti, tx)
+        {
+                LinearExpression *exp = new LinearExpression();
+
+                unsigned int t = tx->get_id();
+                foreach(tx->get_requests(), request)
+                {
+                        unsigned int q = request->get_resource_id();
+
+                        // is it a resource local to Ti?
+                        if (locality[q] == (int) ti.get_cluster())
+                        {
+                                foreach_request_instance(*request, ti, v)
+                                {
+                                        unsigned int var_id;
+                                        var_id = vars.lookup(t, q, v,
+                                                             BLOCKING_PREEMPT);
+                                        exp->add_var(var_id);
+                                }
+                        }
+                }
+                lp.add_equality(exp, num_arrivals);
+        }
+}
+