$ perfetto --query

producers: {
  id: 1
  name: "lazy_producer"
  uid: 0
}
producers: {
  id: 2
  name: "perfetto.traced_probes"
  uid: 0
}
data_sources: {
  producer_id: 1
  descriptor: {
    name: "android.heapprofd"
  }
}
data_sources: {
  producer_id: 2
  descriptor: {
    name: "android.log"
  }
}
data_sources: {
  producer_id: 2
  descriptor: {
    name: "android.packages_list"
  }
}
data_sources: {
  producer_id: 2
  descriptor: {
    name: "android.power"
  }
}
data_sources: {
  producer_id: 2
  descriptor: {
    name: "linux.ftrace"
  }
}
data_sources: {
  producer_id: 2
  descriptor: {
    name: "linux.inode_file_map"
  }
}
data_sources: {
  producer_id: 2
  descriptor: {
    name: "linux.process_stats"
  }
}
data_sources: {
  producer_id: 2
  descriptor: {
    name: "linux.sys_stats"
  }
}
num_sessions: 0
num_sessions_started: 0