add cache set tests

README.md

@@ -0,0 +1,9 @@
+# Repetition tester
+
+For: https://www.computerenhance.com/
+
+Zig version used: 0.12.0
+
+## Linux calling convention register order
+
+RDI, RSI, RDX, RCX, R8, R9, [XYZ]MM0–7

build.zig

@@ -1,7 +1,7 @@
 const std = @import("std");
-const Builder = std.build.Builder;
+const Build = std.Build;
 
-fn addLinuxAssembly(b: *Builder, filename: []const u8) !std.Build.LazyPath {
+fn addLinuxAssembly(b: *Build, filename: []const u8) !std.Build.LazyPath {
     const obj_basename = try std.mem.concat(b.allocator, u8, &.{
         std.fs.path.stem(filename),
         ".o"
@@ -14,13 +14,13 @@ fn addLinuxAssembly(b: *Builder, filename: []const u8) !std.Build.LazyPath {
     return output_obj;
 }
 
-fn addAllLinuxAssmeblies(b: *Builder, path: []const u8) !std.ArrayList(std.Build.LazyPath) {
+fn addAllLinuxAssmeblies(b: *Build, path: []const u8) !std.ArrayList(std.Build.LazyPath) {
     const allocator = b.allocator;
 
     var linux_assemblies = std.ArrayList(std.Build.LazyPath).init(allocator);
     errdefer linux_assemblies.deinit();
 
-    var dir = try std.fs.cwd().openIterableDir(path, .{ });
+    var dir = try std.fs.cwd().openDir(path, .{ .iterate = true });
     var it = dir.iterate();
     while (try it.next()) |file| {
         if (file.kind != .file) continue;
@@ -37,13 +37,13 @@ fn addAllLinuxAssmeblies(b: *Builder, path: []const u8) !std.ArrayList(std.Build
     return linux_assemblies;
 }
 
-pub fn build(b: *Builder) !void {
+pub fn build(b: *Build) !void {
     const target = b.standardTargetOptions(.{});
     const optimize = b.standardOptimizeOption(.{});
 
     const allocator = b.allocator;
 
-    var dir = try std.fs.cwd().openIterableDir("src", .{ });
+    var dir = try std.fs.cwd().openDir("src", .{ .iterate = true });
     var it = dir.iterate();
     while (try it.next()) |entry| {
         if (entry.kind != .directory) continue;
@@ -56,12 +56,12 @@ pub fn build(b: *Builder) !void {
 
         const exe = b.addExecutable(.{
             .name = entry.name,
-            .root_source_file = .{ .path = main_c },
             .optimize = optimize,
             .target = target
         });
         exe.addIncludePath(.{ .path = program_dir });
         exe.addIncludePath(.{ .path = "src" });
+        exe.addCSourceFile(.{ .file = b.path(main_c) });
         exe.linkLibC();
 
         var assemblies = try addAllLinuxAssmeblies(b, program_dir);

src/13_cache_sets/load_bytes.asm

@@ -0,0 +1,23 @@
+global load_bytes
+
+section .text
+
+; rdi - buffer
+; rsi - inner_loop_count
+; rdx - outer_loop_count
+; rcx - step_size
+load_bytes:
+	align 64
+.outer_loop:
+	mov r8, rdi
+	mov r9, rsi
+	.inner_loop:
+		vmovdqu ymm0, [r8]
+		vmovdqu ymm0, [r8 + 32]
+		add r8, rcx
+		dec r9
+		jnz .inner_loop
+
+	dec rdx
+	jnz .outer_loop
+	ret

src/13_cache_sets/main.c

@@ -0,0 +1,76 @@
+#include "repetition_tester.c"
+#include <sys/mman.h>
+
+void load_bytes(uint8_t *buffer, uint32_t inner_loop, uint32_t outer_loop, uint32_t step_size);
+
+static uint64_t kibibytes(uint64_t count) {
+	return 1024 * count;
+}
+
+static uint64_t mibibytes(uint64_t count) {
+	return 1024 * kibibytes(count);
+}
+
+static uint64_t gibibytes(uint64_t count) {
+	return 1024 * mibibytes(count);
+}
+
+int main() {
+	uint32_t byte_count = kibibytes(16);
+	assert(byte_count % 64 == 0); // Must be divisible by 128
+
+	struct repetitor repetitor = {};
+	repetitor_init(&repetitor);
+	printf("CPU Frequency: %ldHz (~%.2fGHz)\n", repetitor.cpu_freq, (float)repetitor.cpu_freq/(1000*1000*1000));
+
+	uint64_t buffer_size = gibibytes(1);
+	if (buffer_size % 4096) {
+		printf("ERROR: Size of buffer is not page aligned\n");
+		return -1;
+	}
+
+	uint8_t *buffer = mmap(0, buffer_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+	if (buffer == NULL) {
+		printf("ERROR: Failed to allocate buffer\n");
+		return -1;
+	}
+
+	if ((size_t)buffer % 64 != 0) {
+		printf("ERROR: Allocated buffer is not cache line aligned, it is %ld\n", (size_t)buffer % 64);
+		return -1;
+	}
+
+	// Touch pages so they would be mapped in, to avoid page faults during tests
+	for (uint64_t i = 0; i < buffer_size; i += 4096) {
+		buffer[i] = (uint8_t)i;
+	}
+
+	// uint64_t byte_count = unadjusted_byte_count - 64;
+
+	for (int i = 0; i < 128; i++) {
+		uint64_t step_size = i*64;
+
+		uint64_t outer_loop = 64;
+		uint64_t inner_loop = 256;
+
+		repetitor_clear(&repetitor);
+		while (repetitor_repeat(&repetitor, 2)) {
+			repetitor_start(&repetitor);
+			repetitor_measure_start(&repetitor);
+			load_bytes(buffer, inner_loop, outer_loop, step_size);
+			repetitor_measure_stop(&repetitor, outer_loop * inner_loop * 64);
+			repetitor_stop(&repetitor);
+		}
+
+		// char name[128] = { 0 };
+		// snprintf(name, sizeof(name), "%ld step_size", step_size);
+		// repetitor_print_results_label(&repetitor, name);
+
+		printf("%ld;%f\n", step_size, repetitor_get_best_bandwidth(&repetitor));
+	}
+
+	munmap(buffer, buffer_size);
+
+	return 0;
+}
+