Quoting Chris Wilson (2018-06-19 13:49:16)
> Apply a different sort of stress by timing how long it takes to sync a
> second nop batch in the pipeline. We first start a spinner on the
> engine, then when we know the GPU is active, we submit the second nop;
> start timing as we then release the spinner and wait for the nop to
> complete.
>
> As with every other gem_sync test, it serves two roles. The first is
> that it checks that we do not miss a wakeup under common stressful
> conditions (the more conditions we check, the happier we will be that
> they do not occur in practice). And the second role it fulfils, is that
> it provides a very crude estimate for how long it takes for a nop to
> execute from a running start (we already have a complimentary estimate
> for an idle start).
>
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
<SNIP>
> +static void
> +wakeup_ring(int fd, unsigned ring, int timeout)
> +{
<SNIP>
> + intel_detect_and_clear_missed_interrupts(fd);
> + igt_fork(child, num_engines) {
> + const uint32_t bbe = MI_BATCH_BUFFER_END;
> + struct drm_i915_gem_exec_object2 object;
> + struct drm_i915_gem_execbuffer2 execbuf;
> + double end, this, elapsed, now;
> + unsigned long cycles;
> + uint32_t cmd;
> + igt_spin_t *spin;
> +
> + memset(&object, 0, sizeof(object));
> + object.handle = gem_create(fd, 4096);
> + gem_write(fd, object.handle, 0, &bbe, sizeof(bbe));
> +
> + memset(&execbuf, 0, sizeof(execbuf));
> + execbuf.buffers_ptr = to_user_pointer(&object);
> + execbuf.buffer_count = 1;
> + execbuf.flags = engines[child % num_engines];
> +
> + spin = __igt_spin_batch_new_poll(fd, 0, execbuf.flags);
> + igt_assert(spin->running);
> + cmd = *spin->batch;
> +
> + gem_execbuf(fd, &execbuf);
> +
> + igt_spin_batch_end(spin);
> + gem_sync(fd, object.handle);
> +
> + end = gettime() + timeout;
> + elapsed = 0;
> + cycles = 0;
> + do {
> + *spin->batch = cmd;
> + *spin->running = 0;
igt_spin_batch_reset/resume/whatever...
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Regards, Joonas
_______________________________________________
Intel-gfx mailing list
Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
