overlay: Perf output redirection must be done after mmap()

Effectively you choose to redirect the output of an event instead of
mmapping it directly - but the target must already be mmapped.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

diff --git a/overlay/gpu-perf.c b/overlay/gpu-perf.c
index 78d1756..ef17090 100644 (file)
--- a/overlay/gpu-perf.c
+++ b/overlay/gpu-perf.c
@@ -113,12 +113,10 @@ static int perf_tracepoint_open(struct gpu_perf *gp,
                        return errno;
 
                /* read back the event to establish id->tracepoint */
-               read(fd[n], track, sizeof(track));
+               if (read(fd[n], track, sizeof(track)) < 0)
+                       return errno;
                sample[n].id = track[1];
                sample[n].func = func;
-
-               if (gp->nr_events)
-                       ioctl(fd[n], PERF_EVENT_IOC_SET_OUTPUT, gp->fd[n]);
        }
 
        gp->nr_events++;
@@ -128,23 +126,29 @@ static int perf_tracepoint_open(struct gpu_perf *gp,
 static int perf_mmap(struct gpu_perf *gp)
 {
        int size = (1 + N_PAGES) * gp->page_size;
-       int n;
+       int *fd, i, j;
 
        gp->map = malloc(sizeof(void *)*gp->nr_cpus);
        if (gp->map == NULL)
                return ENOMEM;
 
-       for (n = 0; n < gp->nr_cpus; n++) {
-               gp->map[n] = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, gp->fd[n], 0);
-               if (gp->map[n] == (void *)-1)
+       fd = gp->fd;
+       for (j = 0; j < gp->nr_cpus; j++) {
+               gp->map[j] = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, *fd++, 0);
+               if (gp->map[j] == (void *)-1)
                        goto err;
        }
 
+       for (i = 1; i < gp->nr_events; i++) {
+               for (j = 0; j < gp->nr_cpus; j++)
+                       ioctl(*fd++, PERF_EVENT_IOC_SET_OUTPUT, gp->fd[j]);
+       }
+
        return 0;
 
 err:
-       while (--n > 0)
-               munmap(gp->map[n], size);
+       while (--j > 0)
+               munmap(gp->map[j], size);
        free(gp->map);
        gp->map = NULL;
        return EINVAL;
@@ -207,7 +211,6 @@ static int request_add(struct gpu_perf *gp, const void *event)
 
 static int seqno_start(struct gpu_perf *gp, const void *event)
 {
-       printf ("seqno_start\n");
        return 0;
 }