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Modern CPUs are pushing 1MB L1 and 8MB L2 or more. You can fit a dozen FreeRTOS instances in that space. It would be pretty cool to see someone build a system that used a high end CPU but didn't have any installed ram, though I'm not sure if the CPU microcode would be ok with that.


Those numbers are for all cores. No modern CPU has anywhere near that of L1 and L2 per core.


Modern, no.

Some used to, however.

PA-RISC PA-8200 (1997) had 2MB iCache and dCache, up from 1MB of PA-8000. The last two PA-RISC models did 768kB L1 per core, with 32MB or 64MB of L2


Apple’s p-cores have 192kB L1 (data, another 128k i$) and 4MB L2 per core. The L2 number is at least “close” to what GP said, I guess.


For context, the latest 7950x has 64KB of L1 per core, and 1MB L2


And I know we were talking about L1/2, but Epycs can have over 1GB of total L3.


You could boot Windows XP or Linux in that comfortably. Even run an older web browser or computer game. That’s crazy!


The L2 especially is more than enough for FreeRTOS though, thats 3 times the amount of memory my board has.


In the '80s you could run a fully preemptive-multitasking OS with a point-and-click GUI, games and office applications on 1MB of RAM.




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