Hack: Remap CPUs IDs to match Ludwig's cache topo.

This temporary patch remaps CPU IDs to match Ludwig's
cache topology. Thus, "virtual" CPUs 0 and 1, which share
an L2 cache, are remapped to CPUs 0 and 4.

5 files changed, 62 insertions, 12 deletions

diff --git a/Makefile b/Makefile
index 39a79a7..0ec13cc 100644
--- a/Makefile
+++ b/Makefile
@@ -73,7 +73,7 @@ AR  := ${CROSS_COMPILE}${AR}
 
 all     = lib ${rt-apps}
 rt-apps = cycles base_task rt_launch rtspin release_ts measure_syscall \
-          base_mt_task uncache runtests
+          base_mt_task uncache runtests test_cluster
 
 .PHONY: all lib clean dump-config TAGS tags cscope help
 
@@ -222,6 +222,9 @@ obj-rt_launch = rt_launch.o common.o
 obj-rtspin = rtspin.o common.o
 lib-rtspin = -lrt
 
+obj-test_cluster = test_cluster.o common.o
+lib-test_cluster = -lrt
+
 obj-uncache = uncache.o
 lib-uncache = -lrt
 
diff --git a/bin/rtspin.c b/bin/rtspin.c
index 224a201..3f80448 100644
--- a/bin/rtspin.c
+++ b/bin/rtspin.c
@@ -343,8 +343,9 @@ int main(int argc, char** argv)
         param.cls = class;
         param.budget_policy = (want_enforcement) ?
                         PRECISE_ENFORCEMENT : NO_ENFORCEMENT;
-        if (migrate)
+        if (migrate) {
                 param.cpu = cluster_to_first_cpu(cluster, cluster_size);
+        }
         ret = set_rt_task_param(gettid(), &param);
         if (ret < 0)
                 bail_out("could not setup rt task params");
diff --git a/bin/test_cluster.c b/bin/test_cluster.c
new file mode 100644
index 0000000..3bcdc9f
--- /dev/null
+++ b/bin/test_cluster.c
@@ -0,0 +1,22 @@
+#include <stdio.h>
+#include <assert.h>
+#include "litmus.h"
+
+int main(void)
+{
+        int i;
+        int cluster_sizes[] = {1, 2, 6, 24};
+        for(i = 0; i < sizeof(cluster_sizes)/sizeof(cluster_sizes[0]); ++i)
+        {
+                int size = cluster_sizes[i];
+                int num_clusters = 24/size;
+                int c;
+                printf("Cluster Size: %d\n", size);
+                for(c = 0; c < num_clusters; ++c)
+                {
+                        printf("\tcluster %d -> 1st pcpu %d\n", c, cluster_to_first_cpu(c, size));
+                }
+        }
+
+        return 0;
+}
diff --git a/include/migration.h b/include/migration.h
index 2413e7c..1f80376 100644
--- a/include/migration.h
+++ b/include/migration.h
@@ -16,7 +16,7 @@ int be_migrate_thread_to_cluster(pid_t tid, int cluster, int cluster_sz);
 /* set ignore_rm == 1 to include release master in tid's cpu affinity */
 int __be_migrate_thread_to_cluster(pid_t tid, int cluster, int cluster_sz, int ignore_rm);
 
-int be_migrate_to_cpu(int target_cpu);
+int be_migrate_to_cpu(int target_pcpu);
 int be_migrate_to_partition(int partition);
 int be_migrate_to_cluster(int cluster, int cluster_sz);
 
diff --git a/src/migration.c b/src/migration.c
index 5de81d5..930d594 100644
--- a/src/migration.c
+++ b/src/migration.c
@@ -2,6 +2,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sched.h> /* for cpu sets */
+#include <assert.h>
 #include <unistd.h>
 
 #include "migration.h"
@@ -27,6 +28,28 @@ int num_online_cpus()
         return sysconf(_SC_NPROCESSORS_ONLN);
 }
 
+int ludwig_vcpu_to_pcpu(int vcpu) {
+        static const int LUDWIG_VCPU_TO_PCPU[] = {
+                        0, 4, 8, 12, 16, 20,
+                        1, 5, 9, 13, 17, 21,
+                        2, 6, 10, 14, 18, 22,
+                        3, 7, 11, 15, 19, 23
+        };
+        assert(vcpu < 24 && vcpu >= 0);
+        return LUDWIG_VCPU_TO_PCPU[vcpu];
+}
+
+int ludwig_pcpu_to_vcpu(int pcpu) {
+        static const int LUDWIG_PCPU_TO_VCPU[] = {
+                        0, 6, 12, 18, 1, 7,
+                        13, 19, 2, 8, 14, 20,
+                        3, 9, 15, 21, 4, 10,
+                        16, 22, 5, 11, 17, 23
+        };
+        assert(pcpu < 24 && pcpu >= 0);
+        return LUDWIG_PCPU_TO_VCPU[pcpu];
+}
+
 int partition_to_cpu(int partition)
 {
         int cpu = partition;
@@ -34,7 +57,7 @@ int partition_to_cpu(int partition)
         if (master != -1 && master <= cpu) {
                 ++cpu; /* skip over the release master */
         }
-        return cpu;
+        return ludwig_vcpu_to_pcpu(cpu);
 }
 
 int cluster_to_first_cpu(int cluster, int cluster_sz)
@@ -51,10 +74,10 @@ int cluster_to_first_cpu(int cluster, int cluster_sz)
         if (master == first_cpu)
                 ++first_cpu;
 
-        return first_cpu;
+        return ludwig_vcpu_to_pcpu(first_cpu);
 }
 
-int be_migrate_thread_to_cpu(pid_t tid, int target_cpu)
+int be_migrate_thread_to_cpu(pid_t tid, int target_pcpu)
 {
         cpu_set_t *cpu_set;
         size_t sz;
@@ -63,20 +86,20 @@ int be_migrate_thread_to_cpu(pid_t tid, int target_cpu)
 
         /* TODO: Error check to make sure that tid is not a real-time task. */
 
-        if (target_cpu < 0)
+        if (target_pcpu < 0)
                 return -1;
 
         num_cpus = num_online_cpus();
         if (num_cpus == -1)
                 return -1;
 
-        if (target_cpu >= num_cpus)
+        if (target_pcpu >= num_cpus)
                 return -1;
 
         cpu_set = CPU_ALLOC(num_cpus);
         sz = CPU_ALLOC_SIZE(num_cpus);
         CPU_ZERO_S(sz, cpu_set);
-        CPU_SET_S(target_cpu, sz, cpu_set);
+        CPU_SET_S(target_pcpu, sz, cpu_set);
 
         /* apply to caller */
         if (tid == 0)
@@ -125,7 +148,8 @@ int __be_migrate_thread_to_cluster(pid_t tid, int cluster, int cluster_sz,
 
         for (i = first_cpu; i <= last_cpu; ++i) {
                 if (i != master) {
-                        CPU_SET_S(i, sz, cpu_set);
+                        int pcpu = ludwig_vcpu_to_pcpu(i);
+                        CPU_SET_S(pcpu, sz, cpu_set);
                 }
         }
 
@@ -146,9 +170,9 @@ int be_migrate_thread_to_partition(pid_t tid, int partition)
 }
 
 
-int be_migrate_to_cpu(int target_cpu)
+int be_migrate_to_cpu(int target_pcpu)
 {
-        return be_migrate_thread_to_cpu(0, target_cpu);
+        return be_migrate_thread_to_cpu(0, target_pcpu);
 }
 
 int be_migrate_to_cluster(int cluster, int cluster_sz)