vasilito
2e477bbc90
P53: Change itr_tracker insertion point from line 46 to 47 so it applies after NetworkScheme::new() closing, not inside it. P45: Add log.workspace = true to ixgbed Cargo.toml since P45 adds log::error! usage to ixgbed main.rs.
119 lines
4.3 KiB
Diff
119 lines
4.3 KiB
Diff
diff --git a/drivers/net/e1000d/src/device.rs b/drivers/net/e1000d/src/device.rs
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index 4c518f30..7ba100dd 100644
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--- a/drivers/net/e1000d/src/device.rs
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+++ b/drivers/net/e1000d/src/device.rs
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@@ -26,0 +27 @@ const ICR: u32 = 0xC0;
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+const ITR: u32 = 0xC4;
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@@ -241,0 +243,6 @@ impl Intel8254x {
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+ /// Set the Interrupt Throttling Rate (ITR) register.
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+ /// `interval` is in 256-ns increments. 0 disables throttling.
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+ pub unsafe fn set_itr(&self, interval: u16) {
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+ self.write_reg(ITR, interval as u32);
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+ }
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+
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diff --git a/drivers/net/e1000d/src/itr.rs b/drivers/net/e1000d/src/itr.rs
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new file mode 100644
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index 00000000..aa85a6f2
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--- /dev/null
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+++ b/drivers/net/e1000d/src/itr.rs
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@@ -0,0 +1,81 @@
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+/// Interrupt Throttling Rate (ITR) tracker for e1000d.
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+///
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+/// Dynamically adjusts the interrupt coalescing interval based on packet rate
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+/// to balance latency and CPU overhead.
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+#[derive(Debug)]
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+pub struct ItrTracker {
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+ last_irq_count: u64,
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+ current_itr: u16,
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+ consecutive_low: u32,
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+ consecutive_high: u32,
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+}
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+
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+impl ItrTracker {
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+ /// Target ~8000 interrupts/sec max for low latency.
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+ const LOW_LATENCY_THRESHOLD: u64 = 8000;
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+ /// Target ~2000 interrupts/sec min for CPU efficiency.
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+ const HIGH_THROUGHPUT_THRESHOLD: u64 = 2000;
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+ /// Minimum ITR interval in 256-ns units (~50 µs).
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+ const MIN_ITR: u16 = 200;
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+ /// Default ITR interval in 256-ns units (~256 µs).
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+ const DEFAULT_ITR: u16 = 1000;
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+ /// Maximum ITR interval in 256-ns units (~2 ms).
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+ const MAX_ITR: u16 = 8000;
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+ /// Number of consecutive measurements before adjusting.
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+ const HYSTERESIS: u32 = 3;
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+
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+ pub fn new() -> Self {
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+ Self {
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+ last_irq_count: 0,
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+ current_itr: Self::DEFAULT_ITR,
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+ consecutive_low: 0,
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+ consecutive_high: 0,
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+ }
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+ }
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+
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+ /// Call once per IRQ to update the tracker and return the new ITR value.
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+ /// Returns `None` if no change is needed.
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+ pub fn update(&mut self, irq_count: u64) -> Option<u16> {
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+ let delta = irq_count.saturating_sub(self.last_irq_count);
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+ self.last_irq_count = irq_count;
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+
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+ if delta > Self::LOW_LATENCY_THRESHOLD {
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+ self.consecutive_high += 1;
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+ self.consecutive_low = 0;
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+ if self.consecutive_high >= Self::HYSTERESIS {
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+ self.consecutive_high = 0;
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+ let new_itr = self.current_itr.saturating_mul(2).min(Self::MAX_ITR);
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+ if new_itr != self.current_itr {
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+ self.current_itr = new_itr;
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+ return Some(self.current_itr);
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+ }
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+ }
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+ } else if delta < Self::HIGH_THROUGHPUT_THRESHOLD {
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+ self.consecutive_low += 1;
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+ self.consecutive_high = 0;
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+ if self.consecutive_low >= Self::HYSTERESIS {
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+ self.consecutive_low = 0;
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+ let new_itr = self.current_itr.saturating_div(2).max(Self::MIN_ITR);
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+ if new_itr != self.current_itr {
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+ self.current_itr = new_itr;
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+ return Some(self.current_itr);
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+ }
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+ }
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+ } else {
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+ self.consecutive_low = 0;
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+ self.consecutive_high = 0;
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+ }
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+
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+ None
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+ }
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+
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+ pub fn current_itr(&self) -> u16 {
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+ self.current_itr
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+ }
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+}
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+
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+impl Default for ItrTracker {
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+ fn default() -> Self {
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+ Self::new()
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+ }
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+}
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diff --git a/drivers/net/e1000d/src/main.rs b/drivers/net/e1000d/src/main.rs
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index 373ea9b3..1a4b0667 100644
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--- a/drivers/net/e1000d/src/main.rs
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+++ b/drivers/net/e1000d/src/main.rs
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@@ -8,0 +9 @@ pub mod device;
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+pub mod itr;
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@@ -47,0 +49,2 @@ fn daemon(daemon: daemon::Daemon, mut pcid_handle: PciFunctionHandle) -> ! {
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+ let mut itr_tracker = itr::ItrTracker::new();
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+
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@@ -74,0 +78 @@ fn daemon(daemon: daemon::Daemon, mut pcid_handle: PciFunctionHandle) -> ! {
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+ let mut irq_count: u64 = 0;
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@@ -77,0 +82 @@ fn daemon(daemon: daemon::Daemon, mut pcid_handle: PciFunctionHandle) -> ! {
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+ irq_count += 1;
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@@ -82,0 +88,4 @@ fn daemon(daemon: daemon::Daemon, mut pcid_handle: PciFunctionHandle) -> ! {
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+ if let Some(new_itr) = itr_tracker.update(irq_count) {
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+ unsafe { scheme.adapter().set_itr(new_itr) };
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+ }
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+
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