FTL: Yield futures without overhead
ftl::yield, which lifts T to std::future<T>, incurs the cost of
allocating, ref counting, and locking the latter's shared state.
Consolidate the existing std::future extensions into ftl::Future,
and optimize ftl::yield by including static storage for T within.
Bug: 232436803
Test: simpleperf (-31% cycles in postFramebuffer)
Change-Id: I9a7ca7de17e7af10515de97d2f6a0dfa24e35d7a
diff --git a/services/surfaceflinger/BufferQueueLayer.cpp b/services/surfaceflinger/BufferQueueLayer.cpp
index 6a1a38b..00b7085 100644
--- a/services/surfaceflinger/BufferQueueLayer.cpp
+++ b/services/surfaceflinger/BufferQueueLayer.cpp
@@ -48,7 +48,7 @@
// Interface implementation for Layer
// -----------------------------------------------------------------------
-void BufferQueueLayer::onLayerDisplayed(std::shared_future<FenceResult> futureFenceResult) {
+void BufferQueueLayer::onLayerDisplayed(ftl::SharedFuture<FenceResult> futureFenceResult) {
const sp<Fence> releaseFence = futureFenceResult.get().value_or(Fence::NO_FENCE);
mConsumer->setReleaseFence(releaseFence);