feat: Implement perf window

runtime/include/module.h

@@ -5,6 +5,7 @@
 
 #include "http.h"
 #include "panic.h"
+#include "perf_window.h"
 #include "software_interrupt.h"
 #include "types.h"
 
@@ -37,6 +38,7 @@ struct module {
 	struct indirect_table_entry indirect_table[INDIRECT_TABLE_SIZE];
 	struct sockaddr_in          socket_address;
 	int                         socket_descriptor;
+	struct perf_window          perf_window;
 	int                         port;
 
 	/*

runtime/include/perf_window.h

@@ -0,0 +1,96 @@
+#pragma once
+
+#include <spinlock/fas.h>
+#include <stdint.h>
+
+#define PERF_WINDOW_BUFFER_SIZE 10
+
+struct perf_window {
+	uint64_t          buffer[PERF_WINDOW_BUFFER_SIZE];
+	uint64_t          count;
+	ck_spinlock_fas_t lock;
+	double            mean;
+};
+
+/**
+ * Iterates through the values in the buffer and updates the mean
+ * Not intended to be called directly!
+ * @param self
+ */
+static inline void
+perf_window_update_mean(struct perf_window *self)
+{
+	assert(self != NULL);
+	assert(ck_spinlock_fas_locked(&self->lock));
+
+	uint64_t limit = self->count;
+	if (limit > PERF_WINDOW_BUFFER_SIZE) { limit = PERF_WINDOW_BUFFER_SIZE; }
+
+	uint64_t sum = 0;
+	for (uint64_t i = 0; i < limit; i++) sum += self->buffer[i];
+
+	self->mean = (double)(sum) / limit;
+};
+
+/**
+ * Iterates through the values in the buffer and updates the mean
+ * Not intended to be called directly!
+ * @param self
+ */
+static inline void
+perf_window_initialize(struct perf_window *self)
+{
+	assert(self != NULL);
+
+	ck_spinlock_fas_init(&self->lock);
+	self->count = 0;
+	self->mean  = 0;
+	memset(&self->buffer, 0, sizeof(uint64_t) * PERF_WINDOW_BUFFER_SIZE);
+}
+
+/**
+ * Iterates through the values in the buffer and updates the mean
+ * Not intended to be called directly!
+ * @param self
+ * @param value
+ */
+static inline void
+perf_window_add(struct perf_window *self, uint64_t value)
+{
+	assert(self != NULL);
+
+
+	/* A successful invocation should run for a non-zero amount of time */
+	assert(value > 0);
+
+	ck_spinlock_fas_lock(&self->lock);
+	self->buffer[self->count++ % PERF_WINDOW_BUFFER_SIZE] = value;
+	perf_window_update_mean(self);
+	ck_spinlock_fas_unlock(&self->lock);
+}
+
+/**
+ * Returns mean perf value across all executions
+ * @returns mean or -1 if buffer is empty
+ */
+static inline double
+perf_window_get_mean(struct perf_window *self)
+{
+	assert(self != NULL);
+
+	if (self->count == 0) return -1;
+
+	return self->mean;
+}
+
+/**
+ * Returns the total count of executions
+ * @returns total count
+ */
+static inline uint64_t
+perf_window_get_count(struct perf_window *self)
+{
+	assert(self != NULL);
+
+	return self->count;
+}

runtime/src/module.c

@@ -201,6 +201,9 @@ module_new(char *name, char *path, int32_t argument_count, uint32_t stack_size,
 	/* Add the module to the in-memory module DB */
 	module_database_add(module);
 
+	/* Initialize Perf Window */
+	perf_window_initialize(&module->perf_window);
+
 	/* Start listening for requests */
 	module_listen(module);