105 lines
2.8 KiB
Rust
105 lines
2.8 KiB
Rust
// SPDX-License-Identifier: GPL-2.0
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//! Benchmark for find_bit-like methods in Bitmap Rust API.
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use kernel::alloc::flags::GFP_KERNEL;
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use kernel::bindings;
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use kernel::bitmap::BitmapVec;
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use kernel::error::{code, Result};
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use kernel::prelude::module;
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use kernel::time::{Instant, Monotonic};
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use kernel::ThisModule;
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use kernel::{pr_cont, pr_err};
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const BITMAP_LEN: usize = 4096 * 8 * 10;
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// Reciprocal of the fraction of bits that are set in sparse bitmap.
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const SPARSENESS: usize = 500;
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/// Test module that benchmarks performance of traversing bitmaps.
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struct Benchmark();
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fn test_next_bit(bitmap: &BitmapVec) {
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let time = Instant::<Monotonic>::now();
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let mut cnt = 0;
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let mut i = 0;
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while let Some(index) = bitmap.next_bit(i) {
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cnt += 1;
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i = index + 1;
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// CONFIG_RUST_BITMAP_HARDENED enforces strict bounds.
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if i == BITMAP_LEN {
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break;
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}
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}
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let delta = time.elapsed();
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pr_cont!(
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"\nnext_bit: {:18} ns, {:6} iterations",
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delta.as_nanos(),
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cnt
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);
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}
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fn test_next_zero_bit(bitmap: &BitmapVec) {
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let time = Instant::<Monotonic>::now();
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let mut cnt = 0;
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let mut i = 0;
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while let Some(index) = bitmap.next_zero_bit(i) {
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cnt += 1;
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i = index + 1;
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// CONFIG_RUST_BITMAP_HARDENED enforces strict bounds.
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if i == BITMAP_LEN {
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break;
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}
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}
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let delta = time.elapsed();
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pr_cont!(
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"\nnext_zero_bit: {:18} ns, {:6} iterations",
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delta.as_nanos(),
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cnt
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);
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}
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fn find_bit_test() {
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pr_err!("Benchmark");
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pr_cont!("\nStart testing find_bit() Rust with random-filled bitmap");
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let mut bitmap = BitmapVec::new(BITMAP_LEN, GFP_KERNEL).expect("alloc bitmap failed");
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bitmap.fill_random();
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test_next_bit(&bitmap);
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test_next_zero_bit(&bitmap);
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pr_cont!("\nStart testing find_bit() Rust with sparse bitmap");
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let mut bitmap = BitmapVec::new(BITMAP_LEN, GFP_KERNEL).expect("alloc sparse bitmap failed");
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let nbits = BITMAP_LEN / SPARSENESS;
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for _i in 0..nbits {
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// SAFETY: __get_random_u32_below is safe to call with any u32 argument.
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let bit =
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unsafe { bindings::__get_random_u32_below(BITMAP_LEN.try_into().unwrap()) as usize };
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bitmap.set_bit(bit);
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}
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test_next_bit(&bitmap);
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test_next_zero_bit(&bitmap);
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pr_cont!("\n");
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}
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impl kernel::Module for Benchmark {
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fn init(_module: &'static ThisModule) -> Result<Self> {
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find_bit_test();
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// Return error so test module can be inserted again without rmmod.
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Err(code::EINVAL)
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}
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}
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module! {
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type: Benchmark,
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name: "find_bit_benchmark_rust",
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authors: ["Burak Emir <bqe@google.com>"],
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description: "Module with benchmark for bitmap Rust API",
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license: "GPL v2",
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}
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