### extsort_rsw
* Allocates (RAM-2)/2 as read buffers (RB)
* Each thread allocates write buffer (WB) of size RB/num_threads
* Sort of supports more concurrency.
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### extsort_rsw_2
* Allocates 20 Gib as RB.
* Allocates 1GB WB per thread.
* Single thread loops RB/WB times to finsih writing for that RB read.
* Can't have more threads as more WB can't be created.

* A metric to identify the interference of read and write.
* A metric to measure memory and cpu usage. Wasted cores and unused free mem.

### extsort_rsw_3 
* Why seperate key and value. Send sort objects directly to sort() method.