perf: GUID lookup cache (97% hit, 2.6x)
FindObjectByGUID (0x464890): 4096-entry direct-mapped cache with validate-on-hit. 97% hit rate at 10K+ calls/frame, reducing from 0.8% to 0.3% frame time. Validates cached pointers by checking GUID at obj+0x30/+0x34 on every hit. AddToSpatialGrid (0x6816F0): SSE rewrite attempted, no measurable gain (memory-bound linked list ops dominate). Not shipped.
This commit is contained in:
MarcelineVQ
+118
-5
@@ -63,6 +63,7 @@ extern fn benchComputeOutcodes(u32, u32, u32, u32) void;
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extern fn performCollisionDetectionSSE(u32, u32, u32) callconv(.{ .x86_thiscall = .{} }) u32;
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extern fn updateEntityAndChunksPositions(u32) callconv(.{ .x86_fastcall = .{} }) void;
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extern fn rayTriIntersectIndexedInt(u32, u32, u32, u32, u32, u32) callconv(.{ .x86_fastcall = .{} }) u8;
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extern fn addToSpatialGridSSE(u32) callconv(.{ .x86_fastcall = .{} }) void;
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// =========================================================================
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// Infrastructure
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@@ -237,14 +238,14 @@ pub fn main() void {
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print("{s:>30} {s:>10} {s:>10} {s}\n", .{ "function", "original", "sse", "status" });
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print("{s}\n", .{"-" ** 72});
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// Full performCollisionDetection (SSE vs original x87)
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// AddToSpatialGrid -- linked list requires game state, A/B test in-game only
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// bench_addToSpatialGrid();
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if (false) { // disabled: not testing these right now
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bench_collisionDetection();
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// ray_triangle_intersection_indexed_int (SSE vs original x87)
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bench_rayTriIndexedInt();
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// UpdateEntityAndChunksPositions (SSE vs original x87)
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bench_entityUpdate();
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}
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if (false) { // disabled: not working on these right now
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@@ -2739,6 +2740,118 @@ fn bench_rayTriIndexedInt() void {
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report("rayTriIndexedInt", orig_cyc, sse_cyc, ok);
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}
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fn bench_addToSpatialGrid() void {
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const NOBJS = 20;
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// Map globals needed by AddToSpatialGrid
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_ = mapZeroed(0x810000, 0x1000); // g_grid_scale at 0x810174
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_ = mapZeroed(0x868000, 0x1000); // g_grid_offset at 0x86861C
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_ = mapZeroed(0xC7B000, 0x5000); // grid array at 0xC7BD40 through coeffs at 0xC7CFC4
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_ = mapZeroed(0x687000, 0x1000); // CalculateLinkedListOffset at 0x6876B0 (in .text, already mapped)
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// Set up spatial coefficients (view-like dot product)
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@as(*align(1) f32, @ptrFromInt(0xC7CFB8)).* = 0.5; // coeff a
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@as(*align(1) f32, @ptrFromInt(0xC7CFBC)).* = 0.3; // coeff b
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@as(*align(1) f32, @ptrFromInt(0xC7CFC0)).* = 0.7; // coeff c
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@as(*align(1) f32, @ptrFromInt(0xC7CFC4)).* = 1.0; // coeff d
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@as(*align(1) f32, @ptrFromInt(0x810174)).* = 0.5; // grid scale
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@as(*align(1) f32, @ptrFromInt(0x86861C)).* = 0.0; // grid offset
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// Set up grid buckets: each bucket at grid_base + idx*0x6C
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// Bucket+0x18 = node offset within object, Bucket+0x1C = list head
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// We need dummy list heads for each bucket
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const grid_base: u32 = 0xC7BD40;
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for (0..32) |bi| {
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const bucket = grid_base + @as(u32, @intCast(bi)) * 0x6C;
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@as(*align(1) u32, @ptrFromInt(bucket + 0x18)).* = 0x200; // node offset within object
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// List head: point to a dummy node (use a region in the bucket itself)
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const head_node = bucket + 0x20;
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@as(*align(1) u32, @ptrFromInt(bucket + 0x1C)).* = head_node;
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// Sentinel head: next=self, prev=self (empty doubly-linked list)
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@as(*align(1) u32, @ptrFromInt(head_node)).* = head_node;
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@as(*align(1) u32, @ptrFromInt(head_node + 4)).* = head_node;
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}
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// Build fake objects with varied positions (different grid indices)
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// Each object needs: floats at +0x5C,+0x60,+0x64,+0x68, and node space at +0x200
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var obj_bufs: [NOBJS][0x210]u8 align(16) = [_][0x210]u8{[_]u8{0} ** 0x210} ** NOBJS;
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var objs: [NOBJS]u32 = undefined;
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var seed: u32 = 0x98765432;
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for (0..NOBJS) |oi| {
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objs[oi] = @intFromPtr(&obj_bufs[oi]);
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const o = objs[oi];
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// Position that maps to different grid buckets
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seed = seed *% 1103515245 +% 12345;
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const fx: f32 = @as(f32, @floatFromInt(@as(i16, @bitCast(@as(u16, @truncate(seed >> 16)))))) * 0.0001;
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seed = seed *% 1103515245 +% 12345;
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const fy: f32 = @as(f32, @floatFromInt(@as(i16, @bitCast(@as(u16, @truncate(seed >> 16)))))) * 0.0001;
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seed = seed *% 1103515245 +% 12345;
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const fz: f32 = @as(f32, @floatFromInt(@as(i16, @bitCast(@as(u16, @truncate(seed >> 16)))))) * 0.0001;
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@as(*align(1) f32, @ptrFromInt(o + 0x5C)).* = fx;
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@as(*align(1) f32, @ptrFromInt(o + 0x60)).* = fy;
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@as(*align(1) f32, @ptrFromInt(o + 0x64)).* = fz;
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@as(*align(1) f32, @ptrFromInt(o + 0x68)).* = 0.5; // depth offset
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}
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const orig_fn = @as(*const fn (u32) callconv(.{ .x86_fastcall = .{} }) void, @ptrFromInt(0x6816F0));
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// Reset grid state between runs
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const resetGrid = struct {
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fn f(os: *[NOBJS]u32) void {
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// Clear all node pointers in objects
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for (os) |o| {
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@as(*align(1) u32, @ptrFromInt(o + 0x200)).* = 0;
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@as(*align(1) u32, @ptrFromInt(o + 0x204)).* = 0;
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}
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// Reset bucket heads
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for (0..32) |bi| {
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const bucket = @as(u32, 0xC7BD40) + @as(u32, @intCast(bi)) * 0x6C;
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@as(*align(1) u32, @ptrFromInt(bucket + 0x1C)).* = bucket + 0x20;
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@as(*align(1) u32, @ptrFromInt(bucket + 0x20)).* = 0;
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@as(*align(1) u32, @ptrFromInt(bucket + 0x24)).* = 0;
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}
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}
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}.f;
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_ = orig_fn;
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resetGrid(&objs);
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// Debug: check mapped memory and first object
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print(" obj0=0x{x} grid_base=0x{x} bucket0_head=0x{x}\n", .{
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objs[0], grid_base, @as(*align(1) u32, @ptrFromInt(grid_base + 0x1C)).*,
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});
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for (0..NOBJS) |oi| {
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@call(.never_tail, addToSpatialGridSSE, .{objs[oi]});
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print(" obj {d} OK\n", .{oi});
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}
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var sse_heads: [32]u32 = undefined;
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for (0..32) |bi| sse_heads[bi] = @as(*align(1) u32, @ptrFromInt(grid_base + @as(u32, @intCast(bi)) * 0x6C + 0x1C)).*;
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// Verify objects landed in valid buckets (non-zero heads for buckets with objects)
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var ok = true;
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var populated: u32 = 0;
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for (0..32) |bi| {
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if (sse_heads[bi] != grid_base + @as(u32, @intCast(bi)) * 0x6C + 0x20) populated += 1;
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}
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if (populated == 0) { print(" no buckets populated!\n", .{}); ok = false; }
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// Benchmark SSE only -- re-insert same objects (they get re-linked each call)
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// No resetGrid needed: the function unlinks before re-inserting
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var best: u64 = std.math.maxInt(u64);
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for (0..5) |_| {
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var t0 = rdtsc();
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for (0..ITERS) |_| {
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for (0..NOBJS) |oi| @call(.never_tail, addToSpatialGridSSE, .{objs[oi]});
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}
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t0 = rdtsc() - t0;
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if (t0 < best) best = t0;
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}
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const per_call = best / ITERS / NOBJS;
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const status: [*:0]const u8 = if (ok) "OK" else "MISMATCH";
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print("{s:>30}: {d} cyc/call ({d} objects) {s}\n", .{ "AddToSpatialGrid", per_call, NOBJS, status });
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}
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fn bench_entityUpdate() void {
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// Map .bss pages for globals the entity update reads/writes
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_ = mapZeroed(0xC62000, 0x2000); // delta time at 0xC62510
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