tiny.profiling.allocation

1const std = @import("std");23const json = @import("json.zig");45pub const Metric = struct {6    name: []const u8,7    unit: []const u8,8    value: u128,9};1011pub const Totals = struct {12    saw: bool = false,13    allocation_events: u64 = 0,14    free_events: u64 = 0,15    resize_events: u64 = 0,16    remap_events: u64 = 0,17    allocated_bytes: u128 = 0,1819    pub fn record(self: *Totals, row: std.json.ObjectMap) void {20        const kind = json.string(row.get("kind")) orelse return;21        if (!isEventKind(kind)) return;22        self.saw = true;23        if (std.mem.eql(u8, kind, "alloc")) {24            self.allocation_events +|= 1;25            self.allocated_bytes += json.asU64(row.get("len")) orelse 0;26        } else if (std.mem.eql(u8, kind, "free")) {27            self.free_events +|= 1;28        } else if (std.mem.eql(u8, kind, "resize")) {29            self.resize_events +|= 1;30            if (resizeGrowth(row)) |growth| self.allocated_bytes += growth;31        } else if (std.mem.eql(u8, kind, "remap")) {32            self.remap_events +|= 1;33            if (resizeGrowth(row)) |growth| self.allocated_bytes += growth;34        }35    }3637    pub fn metrics(self: Totals) [5]Metric {38        return .{39            .{ .name = "allocation_events", .unit = "count", .value = self.allocation_events },40            .{ .name = "free_events", .unit = "count", .value = self.free_events },41            .{ .name = "resize_events", .unit = "count", .value = self.resize_events },42            .{ .name = "remap_events", .unit = "count", .value = self.remap_events },43            .{ .name = "allocated_bytes", .unit = "bytes", .value = self.allocated_bytes },44        };45    }46};4748pub fn isMetricName(name: []const u8) bool {49    for ((Totals{}).metrics()) |metric| {50        if (std.mem.eql(u8, name, metric.name)) return true;51    }52    return false;53}5455fn isEventKind(kind: []const u8) bool {56    return std.mem.eql(u8, kind, "alloc") or57        std.mem.eql(u8, kind, "free") or58        std.mem.eql(u8, kind, "resize") or59        std.mem.eql(u8, kind, "remap") or60        std.mem.eql(u8, kind, "allocator");61}6263fn resizeGrowth(row: std.json.ObjectMap) ?u64 {64    const new_len = json.asU64(row.get("new_len")) orelse return null;65    const old_len = json.asU64(row.get("old_len")) orelse json.asU64(row.get("len")) orelse return null;66    if (new_len <= old_len) return null;67    return new_len - old_len;68}6970test "profiling allocation totals summarize events" {71    var arena = std.heap.ArenaAllocator.init(std.testing.allocator);72    defer arena.deinit();73    const allocator = arena.allocator();74    const value = try std.json.parseFromSliceLeaky(std.json.Value, allocator,75        \\{"kind":"resize","old_len":64,"new_len":96}76    , .{});77    var totals = Totals{};78    totals.record(try json.object(value));79    try std.testing.expect(totals.saw);80    try std.testing.expectEqual(@as(u64, 1), totals.resize_events);81    try std.testing.expectEqual(@as(u128, 32), totals.allocated_bytes);82    try std.testing.expect(isMetricName("allocated_bytes"));83    try std.testing.expect(!isMetricName("other"));84}

1pub const allocation = @import("allocation.zig");