Add embassy executor cpu stats

esp-hal-embassy/CHANGELOG.md

@@ -8,7 +8,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 
 ### Added
-
+- Embassy executor CPU stats (#3728)
 
 ### Changed
 

esp-hal-embassy/Cargo.toml

@@ -21,7 +21,7 @@ test  = false
 [dependencies]
 cfg-if                    = "1.0.0"
 critical-section          = "1.2.0"
-esp-hal                   = { version = "1.0.0-beta.1", path = "../esp-hal" }
+esp-hal                   = { version = "1.0.0-beta.1", path = "../esp-hal", features = ["unstable"] }
 portable-atomic           = "1.11.0"
 static_cell               = "2.1.0"
 

esp-hal-embassy/esp_config.yml

@@ -45,3 +45,8 @@ options:
   constraints:
     - type:
         validator: positive_integer
+
+- name: low-power-wait-stats
+  description: Enables statistics for the low-power wait feature. Needs the `low-power-wait` config option to be enabled
+  default:
+    - value: true

esp-hal-embassy/src/executor/thread.rs

@@ -3,16 +3,24 @@
 use core::marker::PhantomData;
 
 use embassy_executor::Spawner;
+#[cfg(all(low_power_wait, low_power_wait_stats))]
+use embassy_time::Instant;
 #[cfg(all(low_power_wait, multi_core))]
 use esp_hal::interrupt::software::SoftwareInterrupt;
 use esp_hal::{interrupt::Priority, system::Cpu};
+#[cfg(all(low_power_wait, low_power_wait_stats))]
+use portable_atomic::AtomicU64;
 #[cfg(low_power_wait)]
 use portable_atomic::{AtomicBool, Ordering};
 
 use super::InnerExecutor;
 
 pub(crate) const THREAD_MODE_CONTEXT: usize = 16;
 
+// Count the ticks the CPU was in wait_impl
+#[cfg(all(low_power_wait, low_power_wait_stats))]
+static SLEEP_TICKS: AtomicU64 = AtomicU64::new(0);
+
 /// global atomic used to keep track of whether there is work to do since sev()
 /// is not available on either Xtensa or RISC-V
 #[cfg(low_power_wait)]
@@ -110,8 +118,15 @@ This will use software-interrupt 3 which isn't available for anything else to wa
         loop {
             unsafe { self.inner.inner.poll() };
 
+            #[cfg(all(low_power_wait, low_power_wait_stats))]
+            let before = Instant::now().as_ticks();
             #[cfg(low_power_wait)]
             Self::wait_impl(cpu);
+            #[cfg(all(low_power_wait, low_power_wait_stats))]
+            {
+                let after = Instant::now().as_ticks();
+                SLEEP_TICKS.fetch_add(after - before, Ordering::Relaxed);
+            }
         }
     }
 
@@ -180,3 +195,52 @@ impl Default for Executor {
         Self::new()
     }
 }
+
+// Based on https://github.com/embassy-rs/embassy/pull/3920
+#[cfg(all(low_power_wait, low_power_wait_stats))]
+pub mod thread_low_power_wait_stats {
+    use embassy_time::Instant;
+    use portable_atomic::Ordering;
+
+    /// Statistics for the thread low power wait usage.
+    pub struct ThreadLowPowerWaitStats {
+        previous_tick: u64,
+        previous_sleep_tick: u64,
+    }
+
+    impl ThreadLowPowerWaitStats {
+        /// Create a new instance of `ThreadLowPowerWaitStats`.
+        /// This initializes the previous tick and sleep tick values
+        /// to the current time and the current sleep tick count.
+        /// Run get_usage() to get the current usage percentage periodically.
+        pub fn new() -> Self {
+            Self {
+                previous_tick: Instant::now().as_ticks(),
+                previous_sleep_tick: super::SLEEP_TICKS.load(Ordering::Relaxed),
+            }
+        }
+
+        /// Get the current usage percentage of the thread low power wait.
+        pub fn get_usage(&mut self) -> f32 {
+            let current_tick = Instant::now().as_ticks();
+            let current_sleep_tick = super::SLEEP_TICKS.load(Ordering::Relaxed);
+
+            // Calculate the ratio of time spent sleeping to total time since last report,
+            // the inverse of which is the time spent busy
+            let sleep_tick_difference = (current_sleep_tick - self.previous_sleep_tick) as f32;
+            let tick_difference = (current_tick - self.previous_tick) as f32;
+            let usage = 1f32 - sleep_tick_difference / tick_difference;
+
+            self.previous_tick = current_tick;
+            self.previous_sleep_tick = current_sleep_tick;
+
+            usage * 100.0
+        }
+    }
+
+    impl Default for ThreadLowPowerWaitStats {
+        fn default() -> Self {
+            Self::new()
+        }
+    }
+}

esp-hal-embassy/src/lib.rs

@@ -55,6 +55,8 @@ mod fmt;
 use esp_hal::timer::{AnyTimer, timg::Timer as TimgTimer};
 pub use macros::embassy_main as main;
 
+#[cfg(all(low_power_wait, low_power_wait_stats, feature = "executors"))]
+pub use self::executor::thread_low_power_wait_stats::ThreadLowPowerWaitStats;
 #[cfg(feature = "executors")]
 pub use self::executor::{Executor, InterruptExecutor};
 use self::time_driver::{EmbassyTimer, Timer};