Issue #38: warn_reset_hwm() silently swallowed non-permission I/O errors
from /proc/self/clear_refs (e.g. missing /proc, read-only procfs, kernel
incompatibility). This left users unaware that VmHWM reset failed and
memory peak data could be contaminated across suites.
Changes:
- runner.rs: all errors now produce a warning with specific failure reason;
PermissionDenied retains 'try running as root' hint; AtomicBool warn-once
prevents duplicate output across 7 suite runs
- main.rs: preflight check now uses warn_reset_hwm() instead of the vague
can_reset_vm_hwm(), sharing the same warn-once mechanism
- metrics.rs: remove dead can_reset_vm_hwm() (no callers remaining)
- tests: add hwm_warned_flag_prevents_reentry and warn_reset_hwm_does_not_panic
Introduce Suite enum (runner.rs) replacing stringly-typed suite matching.
BenchConfig.suites is now Option<Vec<Suite>>, making invalid states
unrepresentable. Unknown suite names produce a clear error listing all
valid values.
Fixes: #37
The reader's line_index and file_size were frozen at open time.
After current_line exceeded the initial 150K lines, get_line_impl
returned None for all subsequent reads. With the background thread
appending ~10K lines/sec, ~40% of measured frame latencies were
actually the cost of a None return, not real I/O.
- Add PreadReaderCore::refresh_index(&mut self): seek to start,
rebuild LineIndex, update file_size, invalidate read cache
- Add PreadReaderPlain::refresh_index forwarding method
- Add ReadCache::invalidate to force cache miss after reindex
- Rewrite bench_scroll_during_append: time-based refresh (250ms),
only record latencies for successful reads, assert max_line > initial
- Add regression tests for refresh_index with appended lines
Add BufWriter::with_capacity(64KB) to generate_test_file,
generate_growable_file, and append_lines in data_gen.rs.
Previously each writeln! triggered an individual write syscall,
making 5GB/74M-line benchmark data generation extremely slow.
BufWriter batches writes into 64KB chunks, reducing syscalls
by ~1000x.
Explicit flush()? + drop before subsequent reads ensures data
visibility and propagates flush errors (BufWriter::drop swallows
them).
Closes#35
Replace `static mut OLD_SIGBUS_HANDLER` with AtomicU8 + AtomicPtr to
remove data race UB when concurrent benchmarks call open() from multiple
threads.
Key changes:
- Use `Once::call_once` to guarantee single handler installation
- Publish old handler to atomics BEFORE installing new handler (closes
the handler-active-but-state-unpublished race window)
- Read atomics with Acquire in signal handler (async-signal-safe)
- Align si_addr to page boundary before mmap(MAP_FIXED)
- Add concurrent test: 8 threads open all 5 variants simultaneously
