While digging through long execution traces working on the ftrace
bug I noticed we weren't really varying the "cpu" or "pid" values
very much. This attempts to add a bit more variety.
Signed-off-by: Vince Weaver <vincent.weaver@xxxxxxxxx>
diff --git a/syscalls/perf_event_open.c b/syscalls/perf_event_open.c
index 87a0522..2ff004e 100644
--- a/syscalls/perf_event_open.c
+++ b/syscalls/perf_event_open.c
@@ -6,6 +6,7 @@
#include <stdlib.h>
#include <string.h>
+#include <unistd.h>
#include <sys/types.h>
#include <dirent.h>
#include <errno.h>
@@ -1144,10 +1145,20 @@ void sanitise_perf_event_open(int childno)
memset(page_rand, 0, sizeof(struct perf_event_attr));
/* cpu */
- /* requires ROOT to select CPU if paranoid level not 0 */
+ /* requires ROOT to select specific CPU if pid==-1 (all processes) */
/* -1 means all CPUs */
- //shm->a3[childno] = cpu;
- // the default get_cpu() is good enough here
+
+ switch(rand() % 2) {
+ case 0:
+ /* Any CPU */
+ shm->a3[childno] = -1;
+ break;
+ case 1:
+ /* Default to the get_cpu() value */
+ /* set by ARG_CPU */
+ default:
+ break;
+ }
/* group_fd */
/* should usually be -1 or another perf_event fd */
@@ -1187,18 +1198,28 @@ void sanitise_perf_event_open(int childno)
/* pid */
/* requires ROOT to select pid that doesn't belong to us */
- /* pid of 0 means current process */
- /* pid of -1 means all processes */
if (flags & PERF_FLAG_PID_CGROUP) {
/* In theory in this case we should pass in */
/* a file descriptor from /dev/cgroup */
pid = get_random_fd();
} else {
- if (rand_bool()) {
+ switch(rand() % 4) {
+ case 0: /* use current thread */
pid = 0;
- } else {
+ break;
+ case 1: /* get an arbitrary pid */
pid = get_pid();
+ break;
+ case 2: /* measure *all* pids. Might require root */
+ pid = -1;
+ break;
+ case 3: /* measure our actual pid */
+ pid=getpid();
+ break;
+ default:
+ pid = 0;
+ break;
}
}
shm->a2[childno] = pid;
--
To unsubscribe from this list: send the line "unsubscribe trinity" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
