FW/Topology: fix num_packages() in -f exec mode (i.e. Windows)

We weren't rebuilding the cached topology if the resulting set was the
same as the original. In general, that's a good thing, except when there
was no cached topology in the first place...

Signed-off-by: Thiago Macieira <thiago.macieira@intel.com>

bats/sanity-check/20-selftests.bats

@@ -1735,6 +1735,39 @@ selftest_cpuset_negated() {
     selftest_cpuset_negated \!p${cpuinfo[1]}c${cpuinfo[2]}t${cpuinfo[3]} ${cpuinfo[0]}
 }
 
+@test "num_cpus" {
+    declare -A yamldump
+
+    sandstone_selftest -e selftest_skip
+    [[ "$status" -eq 0 ]]
+    test_yaml_regexp "/tests/0/threads/0/messages/0/text" '.*"cpus":\s*'$MAX_PROC'\b.*'
+}
+
+@test "num_packages" {
+    declare -A yamldump
+    sandstone_selftest -e selftest_skip --cpuset=p0
+    [[ "$status" -eq 0 ]]
+    test_yaml_regexp "/tests/0/threads/0/messages/0/text" '.*"packages":\s*1\b.*'
+
+    # attempt to run on two sockets
+    export SANDSTONE_MOCK_TOPOLOGY='0 1 0:1 1:1'
+    run $SANDSTONE --cpuset=p1 --dump-cpu-info
+    if [[ $status -ne 0 ]]; then
+        skip "Test only works with Debug builds (to mock the topology) or multi-socket systems"
+    fi
+
+    sandstone_selftest -e selftest_skip --cpuset=p0c0,p1c0 --no-slicing
+    test_yaml_regexp "/tests/0/threads/0/messages/0/text" '.*"packages":\s*2\b.*'
+
+    # now let's try 4 sockets
+    export SANDSTONE_MOCK_TOPOLOGY='0 1 2 3'
+    run $SANDSTONE --cpuset=p3 --dump-cpu-info
+    if [[ $status -eq 0 ]]; then
+        sandstone_selftest -e selftest_skip --cpuset=p0c0,p1c0,p2c0,p3c0 --no-slicing
+        test_yaml_regexp "/tests/0/threads/0/messages/0/text" '.*"packages":\s*4\b.*'
+    fi
+}
+
 # Confirm that we are roughly using the threads we said we would
 @test "thread usage" {
     local -a cpuset=(`$SANDSTONE --dump-cpu-info | awk '/^[0-9]/ { print $1 }'`)

framework/selftest.cpp

@@ -204,6 +204,7 @@ static int selftest_cxxthrowcatch_run(struct test *test, int cpu)
 
 static int selftest_skip_init(struct test *test)
 {
+    log_info("{\"packages\": %d, \"cpus\": %d}", num_packages(), num_cpus());
     log_info("Requesting skip (this message should be visible)");
     return EXIT_SKIP;
 }

framework/topology.cpp

@@ -1084,10 +1084,11 @@ void restrict_topology(CpuRange range)
     assert(range.starting_cpu + range.cpu_count <= sApp->thread_count);
     auto old_cpu_info = std::exchange(cpu_info, sApp->shmem->cpu_info + range.starting_cpu);
     int old_thread_count = std::exchange(sApp->thread_count, range.cpu_count);
-    if (old_cpu_info == cpu_info && old_thread_count == sApp->thread_count)
-        return;
 
-    cached_topology() = build_topology();
+    Topology &topo = cached_topology();
+    if (old_cpu_info != cpu_info || old_thread_count != sApp->thread_count ||
+            topo.packages.size() == 0)
+        topo = build_topology();
 }
 
 static char character_for_mask(uint32_t mask)