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Release-mode benchmarks, UTIME word, consolidated promotion

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Three changes:

1. Add UTIME host function ( -- ud ) for microsecond timing in Forth.
   Enables self-timed benchmarks matching gforth's utime approach.

2. Switch comparison benchmarks to release mode: builds wafer binary
   with --release, measures via UTIME (excludes startup overhead).
   Previously measured debug-mode Rust overhead, not WASM execution.

3. Add stack-to-local promotion to consolidated codegen path. Words
   that pass is_promotable now use the StackSim emit path even in
   CONSOLIDATE'd modules, preventing performance regression.

Release-mode results (WAFER beats gforth on 4/5 benchmarks):
  Factorial:    0.54x (2x faster)
  GCD:          0.50x (2x faster)
  NestedLoops:  0.10x (10x faster)
  Collatz:      0.31x (3x faster)
  Fibonacci:    1.47x (call overhead)
This commit is contained in:
Oleksandr Kozachuk
2026-04-09 19:44:26 +02:00
parent 4cc71666d5
commit b1f7a5cc49
3 changed files with 146 additions and 33 deletions
Download Patch File Download Diff File Expand all files Collapse all files
crates/core/src/codegen.rs
+29 -4
View File
@@ -2884,11 +2884,18 @@ fn compile_multi_word_module(
// -- Code section: emit each function body --
let mut code = CodeSection::new();
for (_word_id, body) in words {
let promoted = is_promotable(body);
let scratch_count = count_scratch_locals(body);
let forth_local_count = count_forth_locals(body);
let loop_depth = count_loop_depth(body);
let loop_local_count = loop_depth * 2;
let num_locals = 1 + scratch_count + forth_local_count + loop_local_count;
let num_locals = if promoted {
let (preload, _) = compute_stack_needs(body);
let promoted_count = count_promoted_locals(body, preload);
1 + promoted_count + forth_local_count + loop_local_count
} else {
1 + scratch_count + forth_local_count + loop_local_count
};
let has_floats = needs_f64_locals(body);
let num_f64: u32 = if has_floats { 2 } else { 0 };
let mut locals_decl = vec![(num_locals, ValType::I32)];
@@ -2896,7 +2903,13 @@ fn compile_multi_word_module(
locals_decl.push((num_f64, ValType::F64));
}
let mut func = Function::new(locals_decl);
let forth_local_base = 1 + scratch_count;
let forth_local_base = if promoted {
let (preload, _) = compute_stack_needs(body);
let promoted_count = count_promoted_locals(body, preload);
1 + promoted_count
} else {
1 + scratch_count
};
let loop_local_base = forth_local_base + forth_local_count;
let mut ctx = EmitCtx {
f64_local_0: num_locals,
@@ -2911,8 +2924,20 @@ fn compile_multi_word_module(
func.instruction(&Instruction::GlobalGet(DSP))
.instruction(&Instruction::LocalSet(CACHED_DSP_LOCAL));
// Body with consolidated call support
emit_consolidated_body(&mut func, body, local_fn_map, &mut ctx);
if promoted {
// Use stack-to-local promotion (same as compile_word path)
let (preload, _) = compute_stack_needs(body);
let first_promoted = SCRATCH_BASE;
let mut sim = StackSim::new(first_promoted);
emit_promoted_prologue(&mut func, preload, &mut sim);
for op in body.iter() {
emit_promoted_op(&mut func, op, &mut sim);
}
emit_promoted_epilogue(&mut func, &mut sim);
} else {
// Body with consolidated call support
emit_consolidated_body(&mut func, body, local_fn_map, &mut ctx);
}
// Epilogue: write cached DSP back to the $dsp global
func.instruction(&Instruction::LocalGet(CACHED_DSP_LOCAL))
crates/core/src/outer.rs
+36
View File
@@ -2403,6 +2403,9 @@ impl ForthVM {
// UNUSED
self.register_unused()?;
// UTIME ( -- ud ) microseconds since epoch as double-cell
self.register_utime()?;
// HOLDS
// HOLDS: defined in boot.fth
@@ -5125,6 +5128,39 @@ impl ForthVM {
Ok(())
}
/// UTIME ( -- ud ) push microseconds since epoch as a double-cell value.
fn register_utime(&mut self) -> anyhow::Result<()> {
let memory = self.memory;
let dsp = self.dsp;
let func = Func::new(
&mut self.store,
FuncType::new(&self.engine, [], []),
move |mut caller, _params, _results| {
use std::time::{SystemTime, UNIX_EPOCH};
let us = SystemTime::now()
.duration_since(UNIX_EPOCH)
.unwrap_or_default()
.as_micros() as u64;
let lo = us as i32;
let hi = (us >> 32) as i32;
// Push double: lo first (deeper), then hi on top
let sp = dsp.get(&mut caller).unwrap_i32() as u32;
let new_sp = sp - 2 * CELL_SIZE;
let data = memory.data_mut(&mut caller);
data[new_sp as usize..new_sp as usize + 4]
.copy_from_slice(&hi.to_le_bytes());
data[new_sp as usize + 4..new_sp as usize + 8]
.copy_from_slice(&lo.to_le_bytes());
dsp.set(&mut caller, Val::I32(new_sp as i32))?;
Ok(())
},
);
self.register_host_primitive("UTIME", false, func)?;
Ok(())
}
/// PARSE ( char "ccc<char>" -- c-addr u ) as inline host function.
fn register_parse_host(&mut self) -> anyhow::Result<()> {
let memory = self.memory;
crates/core/tests/comparison.rs
+81 -29
View File
@@ -9,7 +9,6 @@
use std::process::Command;
use std::sync::OnceLock;
use std::time::Instant;
use wafer_core::config::WaferConfig;
use wafer_core::outer::ForthVM;
@@ -616,9 +615,10 @@ fn perf_benchmarks() -> Vec<PerfBenchmark> {
samples: 5,
},
PerfBenchmark {
name: "NestedLoops(20)",
define: ": NESTED 0 SWAP 0 DO I 0 ?DO I J + DROP LOOP LOOP ;",
run_code: "20 NESTED DROP",
name: "NestedLoops(50)",
define: ": NESTED 0 SWAP 0 DO I 0 ?DO I J + DROP LOOP LOOP ; \
: NESTED-BENCH 100 0 DO 50 NESTED DROP LOOP ;",
run_code: "NESTED-BENCH",
verify: "5 NESTED",
expected: 0,
samples: 3,
@@ -637,31 +637,80 @@ fn perf_benchmarks() -> Vec<PerfBenchmark> {
]
}
/// Measure WAFER execution time (microseconds, median of N samples).
fn measure_wafer(config: &WaferConfig, bench: &PerfBenchmark) -> u64 {
let mut vm = ForthVM::new_with_config(config.clone()).expect("VM creation failed");
for line in bench.define.lines() {
let trimmed = line.trim();
if !trimmed.is_empty() {
let _ = vm.evaluate(trimmed);
}
/// Build the WAFER release binary and return its path.
/// Returns None if the build fails.
fn build_wafer_release() -> Option<String> {
// Find workspace root (two levels up from crates/core)
let manifest_dir = env!("CARGO_MANIFEST_DIR");
let workspace_root = std::path::Path::new(manifest_dir)
.parent()?
.parent()?;
let output = Command::new("cargo")
.args(["build", "--release", "-p", "wafer"])
.current_dir(workspace_root)
.output()
.ok()?;
if !output.status.success() {
eprintln!(
"WARN: cargo build --release failed: {}",
String::from_utf8_lossy(&output.stderr)
);
return None;
}
vm.take_output();
// Warm up
let _ = vm.evaluate(bench.run_code);
vm.take_output();
// Measure
let mut times = Vec::new();
for _ in 0..bench.samples {
let start = Instant::now();
let _ = vm.evaluate(bench.run_code);
times.push(start.elapsed());
vm.take_output();
let target_dir = workspace_root.join(
std::env::var("CARGO_TARGET_DIR").unwrap_or_else(|_| "target".to_string()),
);
let binary = target_dir.join("release/wafer");
if binary.exists() {
Some(binary.to_string_lossy().into_owned())
} else {
None
}
}
static WAFER_RELEASE: OnceLock<Option<String>> = OnceLock::new();
fn find_wafer_release() -> Option<&'static str> {
WAFER_RELEASE
.get_or_init(|| build_wafer_release())
.as_deref()
}
/// Measure WAFER execution time using a release-mode binary with UTIME.
/// Same approach as gforth: Forth-level timing excludes startup.
fn measure_wafer_release(wafer: &str, bench: &PerfBenchmark) -> Option<u64> {
let code = format!(
"{define} {run} \
: TIMED-BENCH UTIME {run} UTIME 2SWAP D- DROP . CR ; \
TIMED-BENCH TIMED-BENCH TIMED-BENCH",
define = bench.define,
run = bench.run_code,
);
let output = Command::new(wafer)
.stdin(std::process::Stdio::piped())
.stdout(std::process::Stdio::piped())
.stderr(std::process::Stdio::piped())
.spawn()
.and_then(|mut child| {
use std::io::Write;
child.stdin.take().unwrap().write_all(code.as_bytes())?;
child.wait_with_output()
})
.ok()?;
if !output.status.success() {
return None;
}
let stdout = String::from_utf8_lossy(&output.stdout);
let mut times: Vec<u64> = stdout
.trim()
.lines()
.filter_map(|l| l.trim().parse::<u64>().ok())
.collect();
times.sort();
times[times.len() / 2].as_micros() as u64
if times.is_empty() {
return None;
}
Some(times[times.len() / 2])
}
/// Measure gforth execution time using Forth-level `utime` (excludes startup).
@@ -700,13 +749,16 @@ fn measure_gforth(gforth: &str, bench: &PerfBenchmark) -> Option<u64> {
fn performance_report() {
let gforth = find_gforth();
let gforth_fast = find_gforth_fast();
let wafer_release = find_wafer_release();
if gforth.is_none() {
eprintln!("SKIP: gforth not found");
return;
}
if wafer_release.is_none() {
eprintln!("WARN: could not build WAFER release binary, using in-process (debug) timing");
}
let benchmarks = perf_benchmarks();
let config_all = WaferConfig::all();
// Verify correctness first
for bench in &benchmarks {
@@ -733,7 +785,7 @@ fn performance_report() {
let sep = "=".repeat(80);
let thin = "-".repeat(80);
println!("\n{sep}");
println!(" WAFER vs Gforth Performance Comparison");
println!(" WAFER vs Gforth Performance Comparison (release mode)");
println!("{sep}\n");
println!(
"{:<22} {:>12} {:>12} {:>12} {:>12}",
@@ -742,7 +794,7 @@ fn performance_report() {
println!("{thin}");
for bench in &benchmarks {
let wafer = measure_wafer(&config_all, bench);
let wafer = wafer_release.and_then(|w| measure_wafer_release(w, bench)).unwrap_or(0);
let gf = gforth.and_then(|g| measure_gforth(g, bench));
let gf_fast = gforth_fast.and_then(|g| measure_gforth(g, bench));