7e307f2160
These were copied from external benchmarks, and tweaked/simplified a bit based on gained experience. I mostly just wanted something to test the bench runner/scripts, with bench_rbyd showcasing a low-level litmus benchmark, and bench_wt showcasing a high-level throughput benchmark. Though bench_wt has proven to be a _very_ versatile benchmark, and will likely be the first stop for getting an understanding of high-level performance implications. --- Also added bench_helpers.h/c, which includes a couple helper functions: - bench_helpers_warmup - Warm up the filesystem by writing a 1 block file 2*block_count times. This is meant to exhaust any preerased state, post-format lookahead buffers, etc. - bench_helpers_usage - Find a tight bound on disk usage. This allocates a bitmap to find the tight bound, unlike lfs3_fs_usage, which is best-effort. However the bitmap is hidden behind BENCH_HEAP_PAUSE to prevent messing with parallel heap measurements.