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 <[email protected]> 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 [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
