Add bit iteration benchmarks

Signed-off-by: Robert Kruszewski <github@robertk.io>

Author: robert3005

Cargo.lock

@@ -56,3 +56,7 @@ harness = false
 [[bench]]
 name = "run_end_take"
 harness = false
+
+[[bench]]
+name = "run_end_filter"
+harness = false

encodings/runend/Cargo.toml

@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-FileCopyrightText: Copyright the Vortex contributors
+
+//! Benchmarks for the run-end filter inner loop (`filter_run_end_primitive`).
+//!
+//! This measures the kernel directly rather than going through the lazy
+//! `ArrayRef::filter` (which only builds a `FilterArray` node and does not run
+//! the kernel). The hot work is a per-run popcount of the predicate mask, which
+//! now uses `BitBuffer::count_range` (SIMD) instead of a bit-by-bit walk.
+
+#![expect(clippy::cast_possible_truncation)]
+#![expect(clippy::cast_precision_loss)]
+#![expect(clippy::cast_sign_loss)]
+#![expect(clippy::expect_used)]
+
+use std::fmt;
+
+use divan::Bencher;
+use rand::SeedableRng;
+use rand::rngs::StdRng;
+use rand::seq::SliceRandom;
+use vortex_buffer::BitBuffer;
+use vortex_runend::_benchmarking::filter_run_end_primitive;
+
+fn main() {
+    divan::main();
+}
+
+#[derive(Clone, Copy)]
+struct FilterBenchArgs {
+    /// Total logical length of the decoded array.
+    length: usize,
+    /// Average run length used when building the run-end array.
+    run_length: usize,
+    /// Fraction of mask bits that are set to `true`.
+    density: f64,
+}
+
+impl fmt::Display for FilterBenchArgs {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(
+            f,
+            "len={}_run={}_density={:.1}",
+            self.length, self.run_length, self.density
+        )
+    }
+}
+
+const FILTER_ARGS: &[FilterBenchArgs] = &[
+    FilterBenchArgs {
+        length: 4_096,
+        run_length: 16,
+        density: 0.1,
+    },
+    FilterBenchArgs {
+        length: 4_096,
+        run_length: 16,
+        density: 0.5,
+    },
+    FilterBenchArgs {
+        length: 4_096,
+        run_length: 16,
+        density: 0.9,
+    },
+    FilterBenchArgs {
+        length: 16_384,
+        run_length: 16,
+        density: 0.1,
+    },
+    FilterBenchArgs {
+        length: 16_384,
+        run_length: 16,
+        density: 0.5,
+    },
+    FilterBenchArgs {
+        length: 16_384,
+        run_length: 16,
+        density: 0.9,
+    },
+];
+
+/// Build the run-end boundaries (cumulative run lengths) for `length` rows.
+fn build_run_ends(length: usize, run_length: usize) -> Vec<u32> {
+    let n_runs = length.div_ceil(run_length);
+    (0..n_runs)
+        .map(|r| (((r + 1) * run_length).min(length)) as u32)
+        .collect()
+}
+
+/// Build a predicate mask of `length` bits with approximately `density` set bits,
+/// shuffled so the set bits are spread across runs.
+fn build_mask(length: usize, density: f64) -> BitBuffer {
+    let n_true = (length as f64 * density).round() as usize;
+    let mut bits = vec![false; length];
+    for b in bits.iter_mut().take(n_true) {
+        *b = true;
+    }
+    let mut rng = StdRng::seed_from_u64(0x5eed);
+    bits.shuffle(&mut rng);
+    BitBuffer::from(bits)
+}
+
+#[divan::bench(args = FILTER_ARGS)]
+fn filter_run_end(bencher: Bencher, args: FilterBenchArgs) {
+    let run_ends = build_run_ends(args.length, args.run_length);
+    let mask = build_mask(args.length, args.density);
+    let length = args.length as u64;
+    bencher
+        .with_inputs(|| (run_ends.clone(), mask.clone()))
+        .bench_refs(|(run_ends, mask)| {
+            filter_run_end_primitive::<u32>(run_ends, 0, length, mask).expect("filter")
+        });
+}

encodings/runend/benches/run_end_filter.rs

@@ -74,7 +74,7 @@ impl FilterKernel for RunEnd {
 }
 
 // Code adapted from apache arrow-rs https://github.com/apache/arrow-rs/blob/b1f5c250ebb6c1252b4e7c51d15b8e77f4c361fa/arrow-select/src/filter.rs#L425
-fn filter_run_end_primitive<R: NativePType + AddAssign + From<bool> + AsPrimitive<u64>>(
+pub fn filter_run_end_primitive<R: NativePType + AddAssign + From<bool> + AsPrimitive<u64>>(
     run_ends: &[R],
     offset: u64,
     length: u64,

encodings/runend/src/compute/filter.rs

@@ -21,6 +21,7 @@ mod rules;
 
 #[doc(hidden)]
 pub mod _benchmarking {
+    pub use compute::filter::filter_run_end_primitive;
     pub use compute::take::take_indices_unchecked;
 
     use super::*;

encodings/runend/src/lib.rs

@@ -200,6 +200,10 @@ required-features = ["_test-harness"]
 name = "dict_mask"
 harness = false
 
+[[bench]]
+name = "validity_is_valid"
+harness = false
+
 [[bench]]
 name = "dict_unreferenced_mask"
 harness = false

vortex-array/Cargo.toml

@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-FileCopyrightText: Copyright the Vortex contributors
+
+//! Benchmarks the cost of checking array-backed [`Validity`] per element.
+//!
+//! For the `Validity::Array` variant, `Validity::execute_is_valid` runs a scalar lookup through
+//! the compute stack on *every* call, and the (now deprecated) `is_valid` additionally spins up a
+//! fresh `ExecutionCtx` per call. Either way, calling it in a `for i in 0..n` loop is
+//! pathologically slow. The fix used by callers is to materialize the validity into a `Mask` once
+//! (`execute_mask`) and then do cheap O(1) bit reads via `Mask::value`. This bench contrasts the two.
+//!
+//! Sizes are kept small because the per-element variant is intentionally the slow one we are
+//! measuring.
+
+#![allow(clippy::unwrap_used)]
+
+use std::sync::LazyLock;
+
+use divan::Bencher;
+use vortex_array::VortexSessionExecute;
+use vortex_array::array_session;
+use vortex_array::validity::Validity;
+use vortex_buffer::BitBuffer;
+use vortex_session::VortexSession;
+
+fn main() {
+    divan::main();
+}
+
+const SIZES: &[usize] = &[256, 1024];
+
+/// Build an array-backed validity (~10% nulls so it is `Validity::Array`).
+fn array_validity(len: usize) -> Validity {
+    Validity::from(BitBuffer::from_iter(
+        (0..len).map(|i| !i.is_multiple_of(10)),
+    ))
+}
+
+static SESSION: LazyLock<VortexSession> = LazyLock::new(array_session);
+
+/// Per-element validity check over array-backed validity (the antipattern). This mirrors the
+/// deprecated `Validity::is_valid(i)`: a fresh `ExecutionCtx` plus a scalar lookup on every call.
+#[divan::bench(args = SIZES)]
+fn is_valid_per_element(bencher: Bencher, len: usize) {
+    let validity = array_validity(len);
+    bencher
+        .with_inputs(|| (&validity, SESSION.create_execution_ctx()))
+        .bench_refs(|(validity, ctx)| {
+            let mut count = 0usize;
+            for i in 0..len {
+                count += validity.execute_is_valid(i, ctx).unwrap() as usize;
+            }
+            count
+        });
+}
+
+/// Materialize the validity into a `Mask` once, then read bits (the fix).
+#[divan::bench(args = SIZES)]
+fn execute_mask_then_value(bencher: Bencher, len: usize) {
+    let validity = array_validity(len);
+    bencher
+        .with_inputs(|| (&validity, SESSION.create_execution_ctx()))
+        .bench_refs(|(validity, ctx)| {
+            let mask = validity.execute_mask(len, ctx).unwrap();
+            let mut count = 0usize;
+            for i in 0..len {
+                count += mask.value(i) as usize;
+            }
+            count
+        });
+}

vortex-array/benches/validity_is_valid.rs

@@ -45,6 +45,7 @@ vortex-utils = { workspace = true, features = ["dashmap"] }
 
 [dev-dependencies]
 anyhow = { workspace = true }
+divan = { workspace = true }
 geo-types = { workspace = true }
 jiff = { workspace = true }
 rstest = { workspace = true }
@@ -54,6 +55,10 @@ vortex-runend = { workspace = true }
 vortex-sequence = { workspace = true }
 wkb = { workspace = true }
 
+[[bench]]
+name = "bool_export"
+harness = false
+
 [lints]
 workspace = true
 

vortex-duckdb/Cargo.toml

@@ -0,0 +1,58 @@
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-FileCopyrightText: Copyright the Vortex contributors
+
+//! Microbenchmark for the bit -> byte-bool unpack performed by `BoolExporter::export`.
+//!
+//! DuckDB stores booleans as one byte per value (`&mut [bool]`), while Vortex stores them
+//! bit-packed in a [`BitBuffer`]. On every boolean column export we unpack a slice of the
+//! bit buffer into the destination byte slice.
+//!
+//! This bench isolates that pure unpacking logic so it can run without a live DuckDB
+//! vector: a reused `Vec<bool>` stands in for the DuckDB byte-bool destination. It compares
+//! the previous implementation (`.iter().collect::<Vec<bool>>()` followed by
+//! `copy_from_slice`) against the new allocation-free direct zip-write.
+
+use divan::Bencher;
+use vortex::buffer::BitBuffer;
+
+fn main() {
+    divan::main();
+}
+
+const SIZES: &[usize] = &[1024, 16_384];
+
+/// Bit densities (true ratio), expressed as `(numerator, denominator)`.
+const DENSITIES: &[(usize, usize)] = &[(1, 2), (1, 10), (9, 10)];
+
+fn make_buffer(len: usize, density: (usize, usize)) -> BitBuffer {
+    let (num, den) = density;
+    // `+ 8` so we can slice off a non-byte-aligned offset, matching real exports.
+    BitBuffer::from_iter((0..len + 8).map(|i| (i % den) < num))
+}
+
+/// Previous implementation: allocate a throwaway `Vec<bool>` then copy into the destination.
+#[divan::bench(args = SIZES, consts = [0usize, 1usize, 2usize])]
+fn old_collect_copy<const DENSITY_IDX: usize>(bencher: Bencher, len: usize) {
+    let buffer = make_buffer(len, DENSITIES[DENSITY_IDX]);
+    bencher
+        .with_inputs(|| vec![false; len])
+        .bench_refs(|dst: &mut Vec<bool>| {
+            // Offset by 1 to exercise a non-byte-aligned slice like the export hot path.
+            dst.copy_from_slice(&buffer.slice(1..(1 + len)).iter().collect::<Vec<bool>>());
+            divan::black_box(&dst);
+        });
+}
+
+/// New implementation: zip the sliced bit iterator directly into the destination slice.
+#[divan::bench(args = SIZES, consts = [0usize, 1usize, 2usize])]
+fn new_zip_write<const DENSITY_IDX: usize>(bencher: Bencher, len: usize) {
+    let buffer = make_buffer(len, DENSITIES[DENSITY_IDX]);
+    bencher
+        .with_inputs(|| vec![false; len])
+        .bench_refs(|dst: &mut Vec<bool>| {
+            for (slot, bit) in dst.iter_mut().zip(buffer.slice(1..(1 + len)).iter()) {
+                *slot = bit;
+            }
+            divan::black_box(&dst);
+        });
+}

vortex-duckdb/benches/bool_export.rs

@@ -37,5 +37,13 @@ harness = false
 name = "rank"
 harness = false
 
+[[bench]]
+name = "valid_counts"
+harness = false
+
+[[bench]]
+name = "mask_iteration"
+harness = false
+
 [lints]
 workspace = true