vscode源码分析【三】程序的启动逻辑，性能问题的追踪

const contentTracing = require('electron').contentTracing;
		const traceOptions = {
			categoryFilter: args['trace-category-filter'] || '*',
			traceOptions: args['trace-options'] || 'record-until-full,enable-sampling'
		};
		contentTracing.startRecording(traceOptions, () => onReady());

const windows = appInstantiationService.invokeFunction(accessor => this.openFirstWindow(accessor, electronIpcServer, sharedProcessClient));

	private stopTracingEventually(windows: ICodeWindow[]): void {
		this.logService.info(`Tracing: waiting for windows to get ready...`);

		let recordingStopped = false;
		const stopRecording = (timeout: boolean) => {
			if (recordingStopped) {
				return;
			}

			recordingStopped = true; // only once

			contentTracing.stopRecording(join(homedir(), `${product.applicationName}-${Math.random().toString(16).slice(-4)}.trace.txt`), path => {
				if (!timeout) {
					if (this.windowsMainService) {
						this.windowsMainService.showMessageBox({
							type: 'info',
							message: localize('trace.message', "Successfully created trace."),
							detail: localize('trace.detail', "Please create an issue and manually attach the following file:\n{0}", path),
							buttons: [localize('trace.ok', "Ok")]
						}, this.windowsMainService.getLastActiveWindow());
					}
				} else {
					this.logService.info(`Tracing: data recorded (after 30s timeout) to ${path}`);
				}
			});
		};

		// Wait up to 30s before creating the trace anyways
		const timeoutHandle = setTimeout(() => stopRecording(true), 30000);

		// Wait for all windows to get ready and stop tracing then
		Promise.all(windows.map(window => window.ready())).then(() => {
			clearTimeout(timeoutHandle);
			stopRecording(false);
		});
	}