igt/kms_vblank: Include a test for comparing blocking drmWaitVblank

The other aspect of the spinlock/interrupt on-off overhead is that when
we wait for vblank it immediately turns off, and then we immediately turn
it back on for the next wait.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
This commit is contained in:
Chris Wilson 2015-04-02 11:37:23 +01:00
parent 992f9f6403
commit 590e47c94f

View File

@ -67,12 +67,12 @@ static bool crtc0_active(int fd)
return drmIoctl(fd, DRM_IOCTL_WAIT_VBLANK, &vbl) == 0;
}
static void query(int fd, bool busy)
static void vblank_query(int fd, bool busy)
{
union drm_wait_vblank vbl;
struct timespec start, end;
unsigned long sq, count = 0;
char buf[4096];
struct drm_event_vblank buf;
memset(&vbl, 0, sizeof(vbl));
@ -101,7 +101,46 @@ static void query(int fd, bool busy)
busy ? "busy" : "idle", elapsed(&start, &end, count));
if (busy)
igt_assert_eq(read(fd, buf, sizeof(buf)), sizeof(buf));
igt_assert_eq(read(fd, &buf, sizeof(buf)), sizeof(buf));
}
static void vblank_wait(int fd, bool busy)
{
union drm_wait_vblank vbl;
struct timespec start, end;
unsigned long sq, count = 0;
struct drm_event_vblank buf;
memset(&vbl, 0, sizeof(vbl));
if (busy) {
vbl.request.type = DRM_VBLANK_RELATIVE | DRM_VBLANK_EVENT;
vbl.request.sequence = 72;
do_or_die(drmIoctl(fd, DRM_IOCTL_WAIT_VBLANK, &vbl));
}
vbl.request.type = DRM_VBLANK_RELATIVE;
vbl.request.sequence = 0;
do_or_die(drmIoctl(fd, DRM_IOCTL_WAIT_VBLANK, &vbl));
sq = vbl.reply.sequence;
clock_gettime(CLOCK_MONOTONIC, &start);
do {
vbl.request.type = DRM_VBLANK_RELATIVE;
vbl.request.sequence = 1;
do_or_die(drmIoctl(fd, DRM_IOCTL_WAIT_VBLANK, &vbl));
count++;
} while ((vbl.reply.sequence - sq) <= 60);
clock_gettime(CLOCK_MONOTONIC, &end);
igt_info("Time to wait for %ld/%d vblanks (%s): %7.3fµs\n",
count, (int)(vbl.reply.sequence - sq),
busy ? "busy" : "idle",
elapsed(&start, &end, count));
if (busy)
igt_assert_eq(read(fd, &buf, sizeof(buf)), sizeof(buf));
}
igt_main
@ -116,8 +155,14 @@ igt_main
}
igt_subtest("query-idle")
query(fd, false);
vblank_query(fd, false);
igt_subtest("query-busy")
query(fd, true);
vblank_query(fd, true);
igt_subtest("wait-idle")
vblank_wait(fd, false);
igt_subtest("wait-busy")
vblank_wait(fd, true);
}