overlay: Read interrupts from perf

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

diff --git a/overlay/gem-interrupts.c b/overlay/gem-interrupts.c
index 7377ee7..15dc791 100644 (file)
--- a/overlay/gem-interrupts.c
+++ b/overlay/gem-interrupts.c
@@ -32,50 +32,82 @@
 
 #include "gem-interrupts.h"
 #include "debugfs.h"
+#include "perf.h"
 
-int gem_interrupts_init(struct gem_interrupts *irqs)
+static int perf_open(void)
 {
-       char buf[1024];
-       struct stat st;
+       struct perf_event_attr attr;
 
+       memset(&attr, 0, sizeof (attr));
 
-       memset(irqs, 0, sizeof(*irqs));
+       attr.type = i915_type_id();
+       if (attr.type == 0)
+               return -ENOENT;
+       attr.config = I915_PERF_INTERRUPTS;
+
+       return perf_event_open(&attr, -1, 0, -1, 0);
+}
+
+static int debugfs_open(void)
+{
+       char buf[1024];
+       struct stat st;
 
        sprintf(buf, "%s/i915_gem_interrupt", debugfs_dri_path);
        if (stat(buf, &st))
-               return irqs->error = errno;
+               return errno;
 
        return 0;
 }
 
+int gem_interrupts_init(struct gem_interrupts *irqs)
+{
+       memset(irqs, 0, sizeof(*irqs));
+
+       irqs->fd = perf_open();
+       if (irqs->fd < 0)
+               irqs->error = debugfs_open();
+
+       return irqs->error;
+}
+
 int gem_interrupts_update(struct gem_interrupts *irqs)
 {
-       char buf[8192], *b;
-       int fd, len;
+       uint64_t val;
+       int update;
 
        if (irqs->error)
                return irqs->error;
 
-       sprintf(buf, "%s/i915_gem_interrupt", debugfs_dri_path);
-       fd = open(buf, 0);
-       if (fd < 0)
-               return irqs->error = errno;
-       len = read(fd, buf, sizeof(buf)-1);
-       close(fd);
+       if (irqs->fd < 0) {
+               char buf[8192], *b;
+               int fd, len;
+
+               sprintf(buf, "%s/i915_gem_interrupt", debugfs_dri_path);
+               fd = open(buf, 0);
+               if (fd < 0)
+                       return irqs->error = errno;
+               len = read(fd, buf, sizeof(buf)-1);
+               close(fd);
 
-       if (len < 0)
-               return irqs->error = errno;
+               if (len < 0)
+                       return irqs->error = errno;
 
-       buf[len] = '\0';
+               buf[len] = '\0';
 
-       b = strstr(buf, "Interrupts received:");
-       if (b == NULL)
-               return irqs->error = ENOENT;
+               b = strstr(buf, "Interrupts received:");
+               if (b == NULL)
+                       return irqs->error = ENOENT;
 
-       fd = irqs->last_count == 0;
+               val = strtoull(b + sizeof("Interrupts received:"), 0, 0);
+       } else {
+               if (read(irqs->fd, &val, sizeof(val)) < 0)
+                       return irqs->error = errno;
+       }
+
+       update = irqs->last_count == 0;
        irqs->last_count = irqs->count;
-       irqs->count = strtoull(b + sizeof("Interrupts received:"), 0, 0);
+       irqs->count = val;
        irqs->delta = irqs->count - irqs->last_count;
-
-       return fd ? EAGAIN : 0;
+       return update ? EAGAIN : 0;
 }

diff --git a/overlay/gem-interrupts.h b/overlay/gem-interrupts.h
index e9dbc4a..a818ec8 100644 (file)
--- a/overlay/gem-interrupts.h
+++ b/overlay/gem-interrupts.h
@@ -30,6 +30,7 @@
 struct gem_interrupts {
        long unsigned last_count, count, delta;
        int error;
+       int fd;
 };
 
 int gem_interrupts_init(struct gem_interrupts *irqs);