243 lines
7.4 KiB
Rust
243 lines
7.4 KiB
Rust
//! 透明大页(THP)使用示例
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//!
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//! 展示如何使用透明大页(THP)来减少TLB压力，提高内存访问性能。
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use std::alloc::Layout;
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use vm_mem::{
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init_global_thp_manager, allocate_with_thp, deallocate_with_thp, is_thp_address,
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get_thp_usage_stats, ThpPolicy, TransparentHugePageManager, ThpConfig,
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};
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fn main() -> Result<(), Box<dyn std::error::Error>> {
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println!("透明大页(THP)使用示例");
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// 初始化全局THP管理器
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init_global_thp_manager(ThpPolicy::Transparent)?;
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// 打印THP配置信息
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match TransparentHugePageManager::get_thp_config() {
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Ok(config) => {
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println!("THP配置:");
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println!(" 策略: {:?}", config.enabled);
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println!(" 碎片整理: {}", config.defrag);
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println!(" 使用零页: {}", config.use_zero_page);
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}
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Err(e) => {
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println!("获取THP配置失败: {}", e);
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}
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}
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// 示例1: 基本THP分配
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demo_basic_thp_allocation()?;
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// 示例2: 比较THP与常规分配性能
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demo_performance_comparison()?;
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// 示例3: 检查THP使用统计
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demo_thp_usage_stats()?;
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// 示例4: 不同THP策略的效果
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demo_thp_policies()?;
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Ok(())
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}
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/// 演示基本THP分配
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fn demo_basic_thp_allocation() -> Result<(), Box<dyn std::error::Error>> {
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println!("\n=== 基本THP分配示例 ===");
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// 分配不同大小的内存块
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let sizes = [4096, 65536, 1048576, 16777216]; // 4KB, 64KB, 1MB, 16MB
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for &size in &sizes {
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match allocate_with_thp(size) {
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Ok(ptr) if !ptr.is_null() => {
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println!("成功分配 {} 字节内存，地址: {:p}", size, ptr);
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// 检查是否使用了THP
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let is_thp = is_thp_address(ptr);
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println!(" 使用THP: {}", is_thp);
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// 使用内存...
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unsafe {
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std::ptr::write_bytes(ptr, 0xCC, size);
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}
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// 释放内存
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deallocate_with_thp(ptr, size);
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}
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Ok(_) => {
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println!("分配失败: 返回空指针");
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}
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Err(e) => {
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println!("分配失败: {}", e);
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}
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}
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}
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Ok(())
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}
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/// 演示THP与常规分配的性能比较
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fn demo_performance_comparison() -> Result<(), Box<dyn std::error::Error>> {
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println!("\n=== THP性能比较示例 ===");
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use std::time::Instant;
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let block_size = 2 * 1024 * 1024; // 2MB
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let block_count = 100;
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// 测试THP分配性能
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println!("测试THP分配性能...");
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let thp_start = Instant::now();
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let mut thp_ptrs = Vec::new();
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for _ in 0..block_count {
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match allocate_with_thp(block_size) {
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Ok(ptr) if !ptr.is_null() => {
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thp_ptrs.push(ptr);
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}
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_ => {}
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}
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}
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let thp_alloc_time = thp_start.elapsed();
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// 使用内存
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for &ptr in &thp_ptrs {
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unsafe {
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std::ptr::write_bytes(ptr, 0xDD, block_size);
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}
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}
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// 释放内存
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for ptr in thp_ptrs {
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deallocate_with_thp(ptr, block_size);
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}
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// 测试常规分配性能
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println!("测试常规分配性能...");
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let regular_start = Instant::now();
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let mut regular_ptrs = Vec::new();
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for _ in 0..block_count {
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let layout = Layout::from_size_align(block_size, 8)?;
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let ptr = unsafe { std::alloc::alloc(layout) };
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if !ptr.is_null() {
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regular_ptrs.push(ptr);
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}
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}
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let regular_alloc_time = regular_start.elapsed();
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// 使用内存
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for &ptr in ®ular_ptrs {
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unsafe {
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std::ptr::write_bytes(ptr, 0xEE, block_size);
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}
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}
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// 释放内存
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for ptr in regular_ptrs {
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unsafe {
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let layout = Layout::from_size_align(block_size, 8).unwrap();
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std::alloc::dealloc(ptr, layout);
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}
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}
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// 打印性能比较结果
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println!("性能比较结果:");
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println!(" THP分配时间: {:?}", thp_alloc_time);
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println!(" 常规分配时间: {:?}", regular_alloc_time);
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if thp_alloc_time < regular_alloc_time {
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let speedup = regular_alloc_time.as_nanos() as f64 / thp_alloc_time.as_nanos() as f64;
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println!(" THP加速比: {:.2}x", speedup);
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} else {
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println!(" THP未显示性能优势");
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}
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Ok(())
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}
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/// 演示THP使用统计
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fn demo_thp_usage_stats() -> Result<(), Box<dyn std::error::Error>> {
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println!("\n=== THP使用统计示例 ===");
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match get_thp_usage_stats() {
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Ok(stats) => {
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println!("THP使用统计:");
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println!(" 匿名大页: {}", stats.anon_huge_pages);
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println!(" 共享内存大页: {}", stats.shmem_huge_pages);
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println!(" 总大页: {}", stats.huge_pages_total);
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println!(" 空闲大页: {}", stats.huge_pages_free);
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println!(" 保留大页: {}", stats.huge_pages_reserved);
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println!(" 大页大小: {} kB", stats.huge_page_size);
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if stats.huge_pages_total > 0 {
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let usage_ratio = (stats.huge_pages_total - stats.huge_pages_free) as f64 / stats.huge_pages_total as f64;
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println!(" 大页使用率: {:.1}%", usage_ratio * 100.0);
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}
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}
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Err(e) => {
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println!("获取THP统计失败: {}", e);
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}
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}
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Ok(())
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}
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/// 演示不同THP策略的效果
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fn demo_thp_policies() -> Result<(), Box<dyn std::error::Error>> {
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println!("\n=== THP策略示例 ===");
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let policies = [
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(ThpPolicy::Always, "Always"),
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(ThpPolicy::Never, "Never"),
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(ThpPolicy::Madvise, "Madvise"),
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(ThpPolicy::Transparent, "Transparent"),
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];
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let test_size = 4 * 1024 * 1024; // 4MB
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for (policy, name) in &policies {
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println!("\n测试策略: {}", name);
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// 创建THP管理器
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match TransparentHugePageManager::new(*policy) {
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Ok(manager) => {
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// 测试分配
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match manager.allocate_with_thp(test_size) {
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Ok(ptr) if !ptr.is_null() => {
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println!(" 分配成功: {:p}", ptr);
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// 检查是否使用了THP
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let is_thp = TransparentHugePageManager::is_thp_address(ptr);
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println!(" 使用THP: {}", is_thp);
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// 释放内存
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manager.deallocate_thp(ptr, test_size);
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}
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Ok(_) => {
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println!(" 分配失败: 返回空指针");
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}
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Err(e) => {
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println!(" 分配失败: {}", e);
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}
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}
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// 打印统计信息
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let stats = manager.stats();
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println!(" THP分配: {}",
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stats.thp_allocations.load(std::sync::atomic::Ordering::Relaxed));
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println!(" 常规分配: {}",
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stats.normal_allocations.load(std::sync::atomic::Ordering::Relaxed));
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}
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Err(e) => {
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println!(" 创建THP管理器失败: {}", e);
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}
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}
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}
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Ok(())
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} |