20 Jun
2018
20 Jun
'18
11:04 a.m.
On 2018-Jun-20 08:55:05 +1000, David Arnold <davida(a)pobox.com> wrote:
Does the screen count as I/O?
I was thinking about that as well. 1080p30 video is around 2MBps as H.264 or
about 140MBps as 6bpp raw. The former is negligible, the latter is still shy
of the disparity in CPU power, especially if you take into account the GPU
power needed to do the decoding.
I’d suggest that it’s just that the balance is
(intentionally) quite different. If you squint right, a GPU could look like a channelized
I/O controller.
I agree. Even back then, there was a difference between commercial-oriented
mainframes (the 1401 and 360/50 lineage - which stressed lots of I/O) and the
scientific mainframes (709x, 360/85 - which stressed arithmetic capabilities).
One, not too inaccurate, description of the BCM2835 (RPi SoC) is that it's a
GPU and the sole job of the CPU is to push data into the GPU.
--
Peter Jeremy