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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105// SPDX-License-Identifier: GPL-2.0//! Benchmark for find_bit-like methods in Bitmap Rust API.
use kernel::alloc::flags::GFP_KERNEL;use kernel::bindings;use kernel::bitmap::BitmapVec;use kernel::error::{code, Result};use kernel::prelude::module;use kernel::time::{Instant, Monotonic};use kernel::ThisModule;use kernel::{pr_cont, pr_err};
const BITMAP_LEN: usize = 4096 * 8 * 10;// Reciprocal of the fraction of bits that are set in sparse bitmap.const SPARSENESS: usize = 500;
/// Test module that benchmarks performance of traversing bitmaps.struct Benchmark();
fn test_next_bit(bitmap: &BitmapVec) { let time = Instant::<Monotonic>::now(); let mut cnt = 0; let mut i = 0;
while let Some(index) = bitmap.next_bit(i) { cnt += 1; i = index + 1; // CONFIG_RUST_BITMAP_HARDENED enforces strict bounds. if i == BITMAP_LEN { break; } }
let delta = time.elapsed(); pr_cont!( "\nnext_bit: {:18} ns, {:6} iterations", delta.as_nanos(), cnt );}
fn test_next_zero_bit(bitmap: &BitmapVec) { let time = Instant::<Monotonic>::now(); let mut cnt = 0; let mut i = 0;
while let Some(index) = bitmap.next_zero_bit(i) { cnt += 1; i = index + 1; // CONFIG_RUST_BITMAP_HARDENED enforces strict bounds. if i == BITMAP_LEN { break; } }
let delta = time.elapsed(); pr_cont!( "\nnext_zero_bit: {:18} ns, {:6} iterations", delta.as_nanos(), cnt );}
fn find_bit_test() { pr_err!("Benchmark"); pr_cont!("\nStart testing find_bit() Rust with random-filled bitmap");
let mut bitmap = BitmapVec::new(BITMAP_LEN, GFP_KERNEL).expect("alloc bitmap failed"); bitmap.fill_random();
test_next_bit(&bitmap); test_next_zero_bit(&bitmap);
pr_cont!("\nStart testing find_bit() Rust with sparse bitmap");
let mut bitmap = BitmapVec::new(BITMAP_LEN, GFP_KERNEL).expect("alloc sparse bitmap failed"); let nbits = BITMAP_LEN / SPARSENESS; for _i in 0..nbits { // SAFETY: __get_random_u32_below is safe to call with any u32 argument. let bit = unsafe { bindings::__get_random_u32_below(BITMAP_LEN.try_into().unwrap()) as usize }; bitmap.set_bit(bit); }
test_next_bit(&bitmap); test_next_zero_bit(&bitmap); pr_cont!("\n");}
impl kernel::Module for Benchmark { fn init(_module: &'static ThisModule) -> Result<Self> { find_bit_test(); // Return error so test module can be inserted again without rmmod. Err(code::EINVAL) }}
module! { type: Benchmark, name: "find_bit_benchmark_rust", authors: ["Burak Emir <bqe@google.com>"], description: "Module with benchmark for bitmap Rust API", license: "GPL v2",}