By: Etienne (etienne_lorrain.delete@this.yahoo.fr), July 2, 2013 3:36 am
Room: Moderated Discussions
> > > Your logic simply doesn't hold up. If they just wanted to get flops, the CPU would look like a GPU.
> >
> > That would costs a lot as well.
> >
>
> No it doesn't. GPU can do more flops/watt than a CPU, and more flops/area. Just put a
> little A7 core in one corner to run the OS, and dedicate the rest to a GPGPU array.
Isn't the GPGPU a lot quicker mainly because it does not have to do what the CPU does, i.e. manage virtual memory and memory protection for every bytes (all the TLB work and delays), manage cache lines shared in between CPUs (copying written cache lines to other caches), manage security by erasing newly allocated pages to processes, manage all the crappy hardware around (active waits because some version of that chip do not allow two consecutive writes within N microseconds...), manage different version of libraries (page loaded on demand, position independent code, dynamic linking of files which can be in 10 different places in the filesystem)?
The GPGPU will not help there, and will constantly wait for the "little A7 core" to finish the stuff.
> >
> > That would costs a lot as well.
> >
>
> No it doesn't. GPU can do more flops/watt than a CPU, and more flops/area. Just put a
> little A7 core in one corner to run the OS, and dedicate the rest to a GPGPU array.
Isn't the GPGPU a lot quicker mainly because it does not have to do what the CPU does, i.e. manage virtual memory and memory protection for every bytes (all the TLB work and delays), manage cache lines shared in between CPUs (copying written cache lines to other caches), manage security by erasing newly allocated pages to processes, manage all the crappy hardware around (active waits because some version of that chip do not allow two consecutive writes within N microseconds...), manage different version of libraries (page loaded on demand, position independent code, dynamic linking of files which can be in 10 different places in the filesystem)?
The GPGPU will not help there, and will constantly wait for the "little A7 core" to finish the stuff.