- Renamed BENCH_STACK/HEAP -> BENCH_STACK/HEAP_WATERMARK
- Renamed BENCH_YES_STACK/HEAP -> BENCH_STACK/HEAP
- Tweaked stack/heap watermarks to hopefully be easier to access when
debugging. Now also exposed as global variables
(bench_stack/heap_watermark).
I considered changing BENCH_STACK/HEAP_WATERMARK to be the variable
itself, to be consistent with TEST_PLS, but decided against it:
1. BENCH_STACK_CURRENT() is a bit magic in that it relies on
__attribute__((noinline)) to force a new stack frame. This wouldn't
really be possible with a variable.
2. TEST_PLS is at least constant from the _current run_'s perspective.
This isn't true for the stack/heap watermarks.
- Reworked internals a bit to hopefully be simpler
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.
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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.
Christopher Haster