@@ -66,7 +66,7 @@ int test__expr(struct test *t __maybe_unused, int subtest __maybe_unused)
 {
 	struct expr_id_data *val_ptr;
 	const char *p;
-	double val;
+	double val, num_cpus, num_cores, num_dies, num_packages;
 	int ret;
 	struct expr_parse_ctx *ctx;
 

@@ -161,6 +161,16 @@ int test__expr(struct test *t __maybe_unused, int subtest __maybe_unused)
 			NULL, ctx) == 0);
 	TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 0);
 
+	/* Test toplogy constants appear well ordered. */
+	expr__ctx_clear(ctx);
+	TEST_ASSERT_VAL("#num_cpus", expr__parse(&num_cpus, ctx, "#num_cpus") == 0);
+	TEST_ASSERT_VAL("#num_cores", expr__parse(&num_cores, ctx, "#num_cores") == 0);
+	TEST_ASSERT_VAL("#num_cpus >= #num_cores", num_cpus >= num_cores);
+	TEST_ASSERT_VAL("#num_dies", expr__parse(&num_dies, ctx, "#num_dies") == 0);
+	TEST_ASSERT_VAL("#num_cores >= #num_dies", num_cores >= num_dies);
+	TEST_ASSERT_VAL("#num_packages", expr__parse(&num_packages, ctx, "#num_packages") == 0);
+	TEST_ASSERT_VAL("#num_dies >= #num_packages", num_dies >= num_packages);
+
 	expr__ctx_free(ctx);
 
 	return 0;

@@ -5,6 +5,8 @@
 #include <stdlib.h>
 #include <string.h>
 #include "metricgroup.h"
+#include "cpumap.h"
+#include "cputopo.h"
 #include "debug.h"
 #include "expr.h"
 #include "expr-bison.h"

@@ -375,9 +377,34 @@ double expr_id_data__value(const struct expr_id_data *data)
 
 double expr__get_literal(const char *literal)
 {
+	static struct cpu_topology *topology;
+
 	if (!strcmp("#smt_on", literal))
 		return smt_on() > 0 ? 1.0 : 0.0;
 
+	if (!strcmp("#num_cpus", literal))
+		return cpu__max_present_cpu();
+
+	/*
+	 * Assume that topology strings are consistent, such as CPUs "0-1"
+	 * wouldn't be listed as "0,1", and so after deduplication the number of
+	 * these strings gives an indication of the number of packages, dies,
+	 * etc.
+	 */
+	if (!topology) {
+		topology = cpu_topology__new();
+		if (!topology) {
+			pr_err("Error creating CPU topology");
+			return NAN;
+		}
+	}
+	if (!strcmp("#num_packages", literal))
+		return topology->package_cpus_lists;
+	if (!strcmp("#num_dies", literal))
+		return topology->die_cpus_lists;
+	if (!strcmp("#num_cores", literal))
+		return topology->core_cpus_lists;
+
 	pr_err("Unrecognized literal '%s'", literal);
 	return NAN;
 }