stream_bench/

stream_bench.rs

//! End-to-end stream costs on a prepared GPU. Run with --release.
use hrx::{Constants, Result, Stream};
use std::{collections::BTreeMap, hint::black_box, time::Instant};

fn measure(
    stream: &mut Stream,
    samples: usize,
    operations: usize,
    mut run: impl FnMut(&mut Stream) -> Result<()>,
) -> Result<(f64, f64)> {
    let mut enqueue = Vec::new();
    let mut complete = Vec::new();
    for sample in 0..samples + 3 {
        stream.synchronize()?;
        let start = Instant::now();
        run(stream)?;
        let recorded = start.elapsed();
        stream.synchronize()?;
        let finished = start.elapsed();
        if sample >= 3 {
            enqueue.push(recorded.as_secs_f64() * 1e9 / operations as f64);
            complete.push(finished.as_secs_f64() * 1e9 / operations as f64);
        }
    }
    enqueue.sort_by(f64::total_cmp);
    complete.sort_by(f64::total_cmp);
    Ok((enqueue[samples / 2], complete[samples / 2]))
}

fn main() -> Result<()> {
    let mut stream = Stream::open()?;
    let mut metrics = BTreeMap::new();
    let samples = std::env::var("HRX_BENCH_SAMPLES")
        .ok()
        .and_then(|value| value.parse::<usize>().ok())
        .filter(|&value| value > 0)
        .unwrap_or(9);
    let (ns, _) = measure(&mut stream, samples, 50_000, |stream| {
        for _ in 0..50_000 {
            let buffer = stream.scratch(1024 * 1024)?;
            black_box(&buffer);
            stream.recycle(buffer)?;
        }
        Ok(())
    })?;
    metrics.insert("scratch_reuse_ns", ns);
    let (ns, _) = measure(&mut stream, samples, 2_000, |stream| {
        for _ in 0..2_000 {
            black_box(stream.allocate(1024 * 1024)?);
        }
        Ok(())
    })?;
    metrics.insert("allocate_drop_ns", ns);

    let bytes = 256 * 1024 * 1024;
    let chunk = vec![0x3cu8; 4 * 1024 * 1024];
    let weights = stream.allocate(bytes)?;
    let (_, ns) = measure(&mut stream, samples, 1, |stream| {
        for offset in (0..bytes).step_by(chunk.len()) {
            stream.upload(weights.binding().slice(offset, chunk.len())?, &chunk)?;
        }
        Ok(())
    })?;
    metrics.insert(
        "queued_upload_gib_s",
        bytes as f64 / (1024f64.powi(3) * ns * 1e-9),
    );
    let mut check = [0u8; 16];
    stream.read_blocking(
        weights.try_slice(bytes - check.len(), check.len())?,
        &mut check,
    )?;
    assert_eq!(check, [0x3c; 16]);
    drop(weights);

    let compiler = hrx::loom::Compiler::for_stream(None, &stream)?;
    let module = compiler.module(include_str!("../tests/kernels/euler.loom"));
    let mut spec = hrx::loom::Specialization::new("krea2_euler");
    spec.set_config("krea2.euler.grid_x", "1");
    spec.set_config("krea2.euler.grid_y", "1");
    let artifact = module.compile(&spec)?;
    // This repository owns the source; use its exact dimensions and scalar layout.
    let kernel = unsafe { stream.load_artifact(&artifact)? };
    let sample = stream.allocate(512)?;
    let velocity = stream.allocate(512)?;
    let ones: Vec<u8> = (0..256).flat_map(|_| 0x3f80u16.to_le_bytes()).collect();
    stream.upload_blocking(sample.binding(), &ones)?;
    stream.upload_blocking(velocity.binding(), &ones)?;
    let mut constants = Constants::new();
    match kernel.info().constant_byte_length {
        8 => constants.push(256u32)?,
        12 => constants.push(256u64)?,
        n => return Err(hrx::Error::Message(format!("unexpected constant size {n}"))),
    }
    constants.push(0f32)?;
    let bindings = [sample.binding(), velocity.binding()];
    let (enqueue, complete) = measure(&mut stream, samples, 2048, |stream| {
        for _ in 0..2048 {
            // The source accesses exactly the 256 bf16 elements in each buffer.
            unsafe {
                stream.dispatch(&kernel, [1; 3], [256, 1, 1], &constants, &bindings)?;
            }
        }
        Ok(())
    })?;
    metrics.insert("dispatch_enqueue_ns", enqueue);
    metrics.insert("dispatch_complete_ns", complete);

    // Use disjoint allocations in both graphs. Even an idempotent store is a
    // write: concurrent Euler dispatches cannot share their in/out buffer.
    let mut graph_buffers = Vec::new();
    for _ in 0..32 {
        let sample = stream.allocate(512)?;
        let velocity = stream.allocate(512)?;
        stream.upload(sample.binding(), &ones)?;
        stream.upload(velocity.binding(), &ones)?;
        graph_buffers.push((sample, velocity));
    }
    stream.synchronize()?;
    let mut builder = stream.graph()?;
    let mut previous = None;
    for (sample, velocity) in &graph_buffers {
        let after = previous.as_slice();
        previous = Some(unsafe {
            builder.dispatch(
                after,
                &kernel,
                [1; 3],
                [256, 1, 1],
                &constants,
                &[sample.binding(), velocity.binding()],
            )?
        });
    }
    let chained = builder.finish()?;

    // The same disjoint workloads, this time allowing concurrent scheduling.
    let mut builder = stream.graph()?;
    for (sample, velocity) in &graph_buffers {
        unsafe {
            builder.dispatch(
                &[],
                &kernel,
                [1; 3],
                [256, 1, 1],
                &constants,
                &[sample.binding(), velocity.binding()],
            )?;
        }
    }
    let independent = builder.finish()?;
    let mut graphs = [chained, independent];
    let mut enqueue = [Vec::new(), Vec::new()];
    let mut complete = [Vec::new(), Vec::new()];
    for round in 0..samples + 3 {
        for arm in if round % 2 == 0 { [0, 1] } else { [1, 0] } {
            stream.synchronize()?;
            let start = Instant::now();
            for _ in 0..256 {
                stream.launch(&mut graphs[arm])?;
            }
            let submitted = start.elapsed();
            stream.synchronize()?;
            let elapsed = start.elapsed();
            if round >= 3 {
                enqueue[arm].push(submitted.as_secs_f64() * 1e9 / 256.0);
                complete[arm].push(elapsed.as_secs_f64() * 1e9 / (256.0 * 32.0));
            }
        }
    }
    for values in enqueue.iter_mut().chain(complete.iter_mut()) {
        values.sort_by(f64::total_cmp);
    }
    let ns = complete[0][samples / 2];
    let ns_free = complete[1][samples / 2];
    metrics.insert("graph_enqueue_ns_per_replay", enqueue[0][samples / 2]);
    metrics.insert("graph_complete_ns_per_kernel", ns);
    metrics.insert("graph_independent_ns_per_kernel", ns_free);
    metrics.insert("graph_scheduling_difference_ns_per_kernel", ns - ns_free);
    for (sample, _) in &graph_buffers {
        let mut output = vec![0; 512];
        stream.read_blocking(sample.binding(), &mut output)?;
        assert_eq!(output, ones);
    }
    let mut output = vec![0; 512];
    stream.read_blocking(sample.binding(), &mut output)?;
    assert_eq!(output, ones);
    println!("{}", serde_json::to_string(&metrics)?);
    Ok(())
}