Mainframes used to explore this long ago, leveraging different microcode for different workloads keeping the hardware of processing unit the same, https://en.wikipedia.org/wiki/ZIIP

On the other side of the computing spectrum, there were a couple of papers in 2010s about offloading most common mobile tasks (like CSS layouting) to the specialized mobile CPU subsystems. Maybe this should have been implemented if Google made their own mobile CPU.

ARM got a Javascript oriented instruction: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc....

At least two different tasks, audio and graphics, have special application specific processors. Networking and crypto are also often offloaded.

> one for databases

as a DB guy, there's no 'one task' for DBs . The only thing I can think that is nearly characteristic of DBs I've worked on is that they're IO bound.

That's possibly true of most things except Floating point and graphics.