perf pmu: Add override support for event list CPUID

Add a PERF_CPUID variable to override the CPUID of the current CPU
(within the current architecture). This is useful for testing, so that
all event lists can be tested on a single system.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1473978296-20712-10-git-send-email-sukadev@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/pmu.c

@@ -501,10 +501,16 @@ static void pmu_add_cpu_aliases(struct list_head *head)
 	struct pmu_event *pe;
 	char *cpuid;
 
-	cpuid = get_cpuid_str();
+	cpuid = getenv("PERF_CPUID");
+	if (cpuid)
+		cpuid = strdup(cpuid);
+	if (!cpuid)
+		cpuid = get_cpuid_str();
 	if (!cpuid)
 		return;
 
+	pr_debug("Using CPUID %s\n", cpuid);
+
 	i = 0;
 	while (1) {
 		map = &pmu_events_map[i++];