tests: scheduler queue benchmarks

Implements a set of tests designed to show how the performance of the
three scheduler queue implementations (DUMB, SCALABLE and MULTIQ)
varies with respect to the number of threads in the ready queue.

Signed-off-by: Peter Mitsis <[email protected]>

Author: peter-mitsis

kernel/sched.c

@@ -1599,3 +1599,13 @@ int z_sched_waitq_walk(_wait_q_t  *wait_q,
 
 	return status;
 }
+
+/* This routine exists for benchmarking purposes. It is not used in
+ * general production code.
+ */
+void z_unready_thread(struct k_thread *thread)
+{
+	K_SPINLOCK(&_sched_spinlock) {
+		unready_thread(thread);
+	}
+}

tests/benchmarks/sched_queues/CMakeLists.txt

@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(sched_queues)
+
+FILE(GLOB app_sources src/*.c)
+target_sources(app PRIVATE ${app_sources})
+target_include_directories(app PRIVATE
+  ${ZEPHYR_BASE}/kernel/include
+  ${ZEPHYR_BASE}/arch/${ARCH}/include
+  )

tests/benchmarks/sched_queues/Kconfig

@@ -0,0 +1,30 @@
+# Copyright (c) 2024 Intel Corporation
+# SPDX-License-Identifier: Apache-2.0
+
+mainmenu "Scheduler Queue Benchmark"
+
+source "Kconfig.zephyr"
+
+config BENCHMARK_NUM_ITERATIONS
+	int "Number of iterations to gather data"
+	default 1000
+	help
+	  This option specifies the number of times each test will be executed
+	  before calculating the average times for reporting.
+
+config BENCHMARK_NUM_THREADS
+	int "Number of threads"
+	default 100
+	help
+	  This option specifies the maximum number of threads that the test
+	  will add to the ready queue. Increasing this value will places greater
+	  stress on the ready queue and better highlight the performance
+	  differences as the number of threads in the ready queue changes.
+
+config BENCHMARK_VERBOSE
+	bool "Display detailed results"
+	default y
+	help
+	  This option displays the average time of all the iterations done for
+	  each thread in the tests. This generates large amounts of output. To
+	  analyze it, it is recommended to redirect the output to a file.

tests/benchmarks/sched_queues/README.rst

@@ -0,0 +1,21 @@
+Scheduling Queue Measurements
+#############################
+
+A Zephyr application developer may choose between three different scheduling
+algorithms--dumb, scalable and multiq. These different algorithms have
+different performance characteristics--characteristics that vary as the
+number of ready threads increases. This benchmark can be used to help
+determine which scheduling algorithm may best suit the developer's application.
+
+This benchmark measures the ...
+* Time to add a threads of increasing priority to the ready queue
+* Time to add threads of decreasing priority to the ready queue
+* Time to remove highest priority thread from a wait queue
+* Time to remove lowest priority thread from a wait queue
+
+By default, these tests show the minimum, maximum, and averages of the measured
+times. However, if the verbose option is enabled then the set of measured
+times will be displayed. The following will build this project with verbose
+support:
+
+    EXTRA_CONF_FILE="prj.verbose.conf" west build -p -b <board> <path to project>

tests/benchmarks/sched_queues/prj.conf

@@ -0,0 +1,31 @@
+# Default base configuration file
+
+CONFIG_TEST=y
+
+# eliminate timer interrupts during the benchmark
+CONFIG_SYS_CLOCK_TICKS_PER_SEC=1
+
+# We use irq_offload(), enable it
+CONFIG_IRQ_OFFLOAD=y
+
+# Reduce memory/code footprint
+CONFIG_BT=n
+CONFIG_FORCE_NO_ASSERT=y
+
+CONFIG_TEST_HW_STACK_PROTECTION=n
+# Disable HW Stack Protection (see #28664)
+CONFIG_HW_STACK_PROTECTION=n
+CONFIG_COVERAGE=n
+
+# Disable system power management
+CONFIG_PM=n
+
+CONFIG_TIMING_FUNCTIONS=y
+
+CONFIG_HEAP_MEM_POOL_SIZE=2048
+CONFIG_APPLICATION_DEFINED_SYSCALL=y
+
+# Disable time slicing
+CONFIG_TIMESLICING=n
+
+CONFIG_SPEED_OPTIMIZATIONS=y

tests/benchmarks/sched_queues/prj.verbose.conf

@@ -0,0 +1,4 @@
+# Extra configuration file to enable verbose reporting
+# Use with EXTRA_CONF_FILE
+
+CONFIG_BENCHMARK_VERBOSE=y