perf(core): use quanta::Instant for hot-path timing (#2384)

Replace std::time::Instant with quanta::Instant on per-packet, per-RPC,
and per-session paths. TSC-based, ~5ns vs ~25ns per now() call.

Reuses the existing `extern crate self as hotpath` alias so
`use hotpath::instant::Instant;` resolves to the same quanta type with
or without the hotpath feature. Leaves tokio::time::Instant and
smoltcp::time::Instant untouched.

easytier/src/common/acl_processor.rs

@@ -3,9 +3,11 @@ use std::{
     net::{IpAddr, SocketAddr},
     str::FromStr as _,
     sync::Arc,
-    time::{Duration, Instant, SystemTime, UNIX_EPOCH},
+    time::{Duration, SystemTime, UNIX_EPOCH},
 };
 
+use hotpath::instant::Instant;
+
 use crate::common::{config::ConfigLoader, global_ctx::ArcGlobalCtx, token_bucket::TokenBucket};
 use crate::proto::acl::*;
 use anyhow::Context as _;
@@ -107,10 +109,10 @@ impl AclCacheKey {
 
 // Cache entry with timestamp for LRU cleanup
 #[derive(Debug, Clone)]
-pub struct AclCacheEntry {
+pub(crate) struct AclCacheEntry {
     pub action: Action,
     pub matched_rule: RuleId,
-    pub last_access: std::time::Instant,
+    pub last_access: Instant,
     // New fields to track rule characteristics for proper cache behavior
     pub conn_track_key: Option<String>,
     pub rate_limit_keys: Vec<RateLimitKey>,
@@ -410,7 +412,7 @@ impl AclProcessor {
         }
 
         // Remove oldest entries (LRU cleanup)
-        let mut entries: Vec<(AclCacheKey, std::time::Instant)> = cache
+        let mut entries: Vec<(AclCacheKey, Instant)> = cache
             .iter()
             .map(|entry| (entry.key().clone(), entry.value().last_access))
             .collect();
@@ -431,7 +433,7 @@ impl AclProcessor {
         );
     }
 
-    pub fn process_packet_with_cache_entry(
+    pub(crate) fn process_packet_with_cache_entry(
         &self,
         packet_info: &PacketInfo,
         cache_entry: &AclCacheEntry,

easytier/src/common/stats_manager.rs

@@ -1,9 +1,10 @@
 use dashmap::DashMap;
+use hotpath::instant::Instant;
 use serde::{Deserialize, Serialize};
 use std::cell::UnsafeCell;
 use std::fmt;
 use std::sync::Arc;
-use std::time::{Duration, Instant};
+use std::time::Duration;
 use tokio::time::interval;
 use tokio_util::task::AbortOnDropHandle;
 

easytier/src/common/stun.rs

@@ -2,12 +2,13 @@ use std::collections::BTreeSet;
 use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr};
 use std::sync::atomic::AtomicBool;
 use std::sync::{Arc, RwLock};
-use std::time::{Duration, Instant};
+use std::time::Duration;
 
 use crate::proto::common::{NatType, StunInfo};
 use anyhow::Context;
 use chrono::Local;
 use crossbeam::atomic::AtomicCell;
+use hotpath::instant::Instant;
 use rand::seq::IteratorRandom;
 use socket2::{SockAddr, SockRef};
 use tokio::io::{AsyncReadExt, AsyncWriteExt};
@@ -1312,7 +1313,7 @@ impl StunInfoCollectorTrait for MockStunInfoCollector {
         StunInfo {
             udp_nat_type: self.udp_nat_type as i32,
             tcp_nat_type: NatType::Unknown as i32,
-            last_update_time: std::time::Instant::now().elapsed().as_secs() as i64,
+            last_update_time: Local::now().timestamp(),
             min_port: 100,
             max_port: 200,
             public_ip: vec!["127.0.0.1".to_string(), "::1".to_string()],