Instruments中OSSignpost间隔无法记录显示问题求助

问题描述 #

尝试使用OSSignposter捕获应用中的时间间隔，用于Instruments分析。示例代码在新项目中可正常显示间隔与标记图标，但集成到大型应用后完全无法记录或显示任何间隔。

已做排查 #

• 核对两个应用的oslog配置状态，无差异：

  sudo log config --status --subsystem **.*******.*******.signposttest
  Mode for '**.*******.*******.signposttest'  INFO PERSIST_DEFAULT
  

• 确认工作区与Scheme设置无区别；
• 排查构建设置，未设置OS_ACTIVITY_MODE = disable，尝试调试配置文件无效；
• 不同模式下的异常表现：
  • immediate mode和deferred mode：无标记活动，仅在「List: Events」视图底部面板可见事件；
  • last n seconds mode：时间线无数据、无lanes。

示例代码（双项目测试验证） #

import os.signpost

class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?
    var blackWindow: UIWindow?
    var alertWindow: UIWindow?
    static var originalAppDelegate: AppDelegate!

    var signposter: OSSignposter
    var signpostInterval: OSSignpostIntervalState?

    override init() {
        signposter = OSSignposter(subsystem: Bundle.main.bundleIdentifier ?? "unknown", category: "app")
        signposter.emitEvent(#function)
    }


    func applicationWillResignActive(_ application: UIApplication) {
        guard let interval = signpostInterval else {
            assertionFailure("no interval")
            return
        }
        print("backgrounding, ending active state")
        signposter.endInterval("active", interval)
    }

    func applicationDidBecomeActive(_ application: UIApplication) {
        signpostInterval = signposter.beginInterval("active")
        // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
    }
}

效果对比 #

• 正常效果：
• 问题项目效果：

补充更新 #

通过代码检测发现signposter.isEnabled始终为false，未显式禁用OSSignposter，且无法通过代码手动启用：

signposter = OSSignposter(subsystem: Bundle.main.bundleIdentifier ?? "unknown", category: category)
assert(signposter.isEnabled)

该断言始终触发。

内容的提问来源于stack exchange，提问作者Byron