Kahawai: High-Quality Mobile Gaming Using GPU Offload (Talk)

Speaker Bios

Kahawai, a system that provides high-quality
gaming on mobile devices, such as tablets and smartphones, by offloading
a portion of the GPU computation to server-side infrastructure.
In contrast with previous thin-client approaches that require
a server-side GPU to render the entire content, Kahawai uses
collaborative rendering to combine the output of a mobile GPU and
a server-side GPU into the displayed output. Compared to a thin
client, collaborative rendering requires significantly less network
bandwidth between the mobile device and the server to achieve the
same visual quality and, unlike a thin client, collaborative rendering
supports disconnected operation, allowing a user to play offline
– albeit with reduced visual quality.
Kahawai implements two separate techniques for collaborative
rendering: (1) a mobile device can render each frame with reduced
detail while a server sends a stream of per-frame differences to
transform each frame into a high detail version, or (2) a mobile
device can render a subset of the frames while a server provides the
missing frames. Both techniques are compatible with the hardware accelerated
H.264 video decoders found on most modern mobile
devices. We implemented a Kahawai prototype and integrated it
with the idTech 4 open-source game engine, an advanced engine
used by many commercial games. In our evaluation, we show that
Kahawai can deliver gameplay at an acceptable frame rate, and
achieve high visual quality using as little as one-sixth of the bandwidth
of the conventional thin-client approach. Furthermore, a 50-
person user study with our prototype shows that Kahawai can deliver
the same gaming experience as a thin client under excellent
network conditions.