[mikeash]

1 and 3 are the same thing. I think the best way to address these, if performance is a problem (don't optimize what doesn't need it) is buffering to reduce syscalls, and optimizing the kernel implementation to fix the sort of internal performance problems like the link describes.

For 2, entropy pool depletion is a fictitious problem if you're worried about security. Some discussion here:

https://news.ycombinator.com/item?id=7361694

If you're worried about blocking apps that use /dev/random, the answer there is to fix them to use /dev/urandom so they don't block.