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Autoware vs. Computer Performance @ ROS Japan UG #43 組み込み勉強会
- 1. Kenji Funaoka Autoware vs. Computer Performance @ ROS Japan UG #43 組み込み勉強会 July 17st, 2021 1
- 6. Sensor Configuration 6 https://tier4.jp/media/news/nishio-road-testing/ 様々な自動運転UseCaseに対応できるように配置 LiDAR x 6 Camera x 8
- 7. ECU Configuration CPU Memory SSD GPU Main x2 Core i7-8700 32GB 256GB GTX1660Ti 6GB Camera x6 Jetson Xavier 32GB 32GB Jetson Xavier 7 今回の話題の中心
- 8. CPU高Utilization 8 ROS1からROS2に機械的に置換 画像は ros2 bag record 無し時 有りの場合は 100% に張り付く これは別の自動運転システム どうやって改善していったかの話
- 9. CPU Flame Graph callstack % CPU Time http://www.brendangregg.com/FlameGraphs/cpuflamegraphs.html#FlameGraph perf command インタラクティブに各関数の CPU使用率を確認可能 検索することでマッチした関数の使用率を確認可能 MySQLのCPU Flame Graph
- 10. CONTENTS Multicast Ros2 bag record Multithreaded Executor 10 Data Copy ROS2 Communityやティアフォーでの対策 全部の紹介は難しいため面白かったものを紹介 時系列で色々とあり、論文的な正確性は非考慮 Zero-copy transport むしろこうやって対策すべき！などツッコミも お願いいたします
- 13. Zero-copy transport (3/3) https://github.com/ros2/rclcpp/blob/master/rclcpp/include/rclcpp/experimental/buffers/intra_process_buffer.hpp#L162 shared_ptr→unique_ptr は型変換ができないので、 インスタンスを作り直すしかなく、 This should not happen
- 14. CONTENTS 14 Multicast Ros2 bag record Multithreaded Executor Data Copy Zero-copy transport
- 16. Multicast (2/4) 16 64 recvMC threads x 0.3~0.6%/thread = ~38.4%
- 17. Multicast (3/4) 17 CycloneDDSのConfigurationでAllowMulticast=spdp () 対策 有線接続でのデフォルトは true (full use of multicast) Discovery of participants & endpoints DDSI participants discover each other by means of the Simple Participant Discovery Protocol or SPDP for short. This protocol is based on periodically sending a message containing the specifics of the participant to a set of known addresses. By default, this is a standardised multicast address (239.255.0.1 ; the port number is derived from the domain id) that all DDSI implementations listen to. Particularly important in the SPDP message are the unicast and multicast addresses at which the participant can be reached. Typically, each participant has a unique unicast address, which in practice means all participants on a node all have a different UDP/IP port number in their unicast address. In a multicast-capable network, it doesn’t matter what the actual address (including port number) is, because all participants will learn them through these SPDP messages. The protocol does allow for unicast-based discovery, which requires listing the addresses of machines where participants may be located and ensuring each participant uses one of a small set of port numbers. Because of this, some of the port numbers are derived not only from the domain id, but also from a participant index, which is a small non-negative integer, unique to a participant within a node. (Eclipse Cyclone DDS adds an indirection and uses at most one participant index for a domain for each process, regardless of how many DCPS participants are created by the process.) Once two participants have discovered each other and both have matched the DDSI built-in endpoints their peer is advertising in the SPDP message, the Simple Endpoint Discovery Protocol or SEDP takes over, exchanging information on the DCPS data readers and data writers (and for Eclipse Cyclone DDS, also publishers, subscribers and topics in a manner compatible with OpenSplice) in the two participants. The SEDP data is handled as reliable, transient-local data. Therefore, the SEDP writers send Heartbeats, the SEDP readers detect they have not yet received all samples and send AckNacks requesting retransmissions, the writer responds to these and eventually receives a pure acknowledgement informing it that the reader has now received the complete set. Note that the discovery process necessarily creates a burst of traffic each time a participant is added to the system: all existing participants respond to the SPDP message, following which all start exchanging SEDP data. https://github.com/eclipse-cyclonedds/cyclonedds/blob/master/docs/manual/config.rst#discovery-of-participants--endpoints トピック通信とSEDPはunicast、SPDPはmulticast
- 18. Multicast (4/4)
- 19. CONTENTS 19 Multicast Ros2 bag record Multithreaded Executor Data Copy Zero-copy transport
- 20. Ros2 bag record (1/2) 20
- 21. Ros2 bag record (2/2) 21 https://github.com/ros2/rosbag2/pull/743 sleepを挟んでget_next_executableの負荷削減 負荷は劇的に下がったがあるべき姿ではない https://github.com/ros2/rosbag2/pull/743
- 22. CONTENTS 22 Multicast Ros2 bag record Multithreaded Executor Data Copy Zero-copy transport
- 24. Multithreaded Executor (2/4) MutexTwoPrioritiesでタイマーコールバック重 複排除の排他制御を改善 https://github.com/ros2/rclcpp/pull/1516/files
- 25. Multithreaded Executor (3/4) 25 1. Rollingには入ったがFoxyで使えない 2. Foxyへバックポート https://github.com/ros2/rclcpp/pull/1628 https://github.com/ros2/rclcpp/pull/1636
- 26. Multithreaded Executor (4/4) https://github.com/hsgwa/rclcpp/commit/443df0db3903cae27f4d5fa1681c5dfb9da7a078 26 前述の排他制御のさらなる負荷軽減のため、 スレッド数をデフォルト =論理コア数12から3に削減 レイテンシ伸びる問題もありトレードオフ調整必要 component_containerはスレッド数指定のI/Fがなく rclcppを書き換えておりお勧めできない
- 27. CONTENTS 27 Multicast Ros2 bag record Multithreaded Executor Data Copy Zero-copy transport
- 30. Data Copy (3/3) 30 Memmoveがプロセスの2割 (3割 x 2割で全体の最低6%はメモリコピー） 他プロセスのメモリコピーも考えると競合していそう
- 32. pcl::filter x y z 0 1.1 0 0.1 0.9 0.2 0.3 0.6 0.2 idx 0 1 2 idx’ 0 2 x y z 0 1.1 0 0.3 0.6 0.2 フィルタ前 フィルタ後 リサイズ x y z 0 1.1 0 0.3 0.6 0.2 上からコピー Indexの フィルタ filter(PointCloud& output) filter(Indices &indices) applyFilterIndices(Indices &indices)
- 34. © 2021 Tier IV, Inc. 34