I found this very helpful. It's a 140 pages book and explains relatively abstract how modern gpu hardware works and the programming model.
General-Purpose Graphics Processor Architectures (Tor M. Aamodt)
https://skos.ii.uni.wroc.pl/pluginfile.php/28568/mod_resourc...
> 4. Nvidia, AMD resources are 50% advertising, 50% hype and proprietary jargon.
I found the Nvidia CUDA C Programming Guide very helpful...