Tracing Domain

The Tracing domain provides methods for recording Chrome traces, useful for performance analysis.

Usage

const cdp = @import("cdp");

var tracing = cdp.Tracing.init(&session);

Methods

start

Start trace recording.

pub fn start(self: *Self, opts: StartOptions) !void

StartOptions:

Field	Type	Description
categories	?[]const u8	Trace categories (comma-separated)
options	?[]const u8	Trace options
buffer_usage_reporting_interval	?f64	Interval for buffer usage events
transfer_mode	?[]const u8	"ReportEvents" or "ReturnAsStream"
stream_format	?[]const u8	"json" or "proto"
stream_compression	?[]const u8	"none" or "gzip"
trace_config	?TraceConfig	Detailed trace configuration

Example:

try tracing.start(.{
    .categories = "-*,devtools.timeline,v8.execute,blink.console",
    .transfer_mode = "ReturnAsStream",
});

end

Stop trace recording.

pub fn end(self: *Self) !void

getCategories

Get available trace categories.

pub fn getCategories(self: *Self, allocator: std.mem.Allocator) ![][]const u8

Example:

const categories = try tracing.getCategories(allocator);
defer {
    for (categories) |c| allocator.free(c);
    allocator.free(categories);
}

for (categories) |cat| {
    std.debug.print("Category: {s}\n", .{cat});
}

requestMemoryDump

Request a memory dump during tracing.

pub fn requestMemoryDump(self: *Self, deterministic: ?bool, level_of_detail: ?[]const u8) !MemoryDumpResult

recordClockSyncMarker

Record a clock sync marker for correlating traces.

pub fn recordClockSyncMarker(self: *Self, sync_id: []const u8) !void

Types

TraceConfig

pub const TraceConfig = struct {
    record_mode: ?[]const u8 = null,
    enable_sampling: ?bool = null,
    enable_systrace: ?bool = null,
    enable_argument_filter: ?bool = null,
    included_categories: ?[]const []const u8 = null,
    excluded_categories: ?[]const []const u8 = null,
    synthetic_delays: ?[]const []const u8 = null,
    memory_dump_config: ?MemoryDumpConfig = null,
};

MemoryDumpResult

pub const MemoryDumpResult = struct {
    dump_guid: []const u8,
    success: bool,
};

Common Trace Categories

Category	Description
devtools.timeline	DevTools timeline events
v8.execute	V8 script execution
blink.console	Console API calls
blink.user_timing	User timing API
disabled-by-default-devtools.timeline	Additional timeline info
disabled-by-default-v8.cpu_profiler	V8 CPU profiler

CLI Usage

zchrome dev trace start
zchrome dev trace stop trace.json
zchrome dev trace categories