[Intel-gfx] [PATCH v14] drm/i915: Squash repeated awaits on the same fence

[Chris Wilson]

On Tue, May 02, 2017 at 01:24:58PM +0100, Tvrtko Ursulin wrote:
> On 28/04/2017 20:02, Chris Wilson wrote:
> >+	prandom_seed_state(&prng, i915_selftest.random_seed);
> >+	count = 0;
> >+	kt = ktime_get();
> >+	end_time = jiffies + HZ/10;
> >+	do {
> >+		u32 id = random_engine(&prng);
> >+		u32 seqno = prandom_u32_state(&prng);
> >+
> >+		if (!__intel_timeline_sync_is_later(tl, id, seqno))
> >+			__intel_timeline_sync_set(tl, id, seqno);
> >+
> >+		count++;
> >+	} while (!time_after(jiffies, end_time));
> >+	kt = ktime_sub(ktime_get(), kt);
> >+	kt = ktime_sub_ns(kt, count * prng32_1M / M);
> 
> Two randoms to account here.

Thank you. That fixes the discrepancy between the random_engine results
and using the engines in order.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre