alpinegizmo commented on a change in pull request #15054: URL: https://github.com/apache/flink/pull/15054#discussion_r593021733
########## File path: docs/content/docs/ops/debugging/flame_graphs.md ########## @@ -0,0 +1,83 @@ +--- +title: "Flame Graphs" +weight: 3 +type: docs +aliases: + - /ops/debugging/flame_graphs.html + - /ops/debugging/flame_graphs +--- +<!-- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. +--> + +# Flame Graphs + +[Flame Graphs](http://www.brendangregg.com/flamegraphs.html) are a visualization that effectively surfaces answers to the questions like: +- Which methods are currently consuming CPU resources? +- How consumption by one method compares to the others? Review comment: ```suggestion - How does consumption by one method compare to the others? ``` ########## File path: docs/content/docs/ops/debugging/flame_graphs.md ########## @@ -0,0 +1,83 @@ +--- +title: "Flame Graphs" +weight: 3 +type: docs +aliases: + - /ops/debugging/flame_graphs.html + - /ops/debugging/flame_graphs +--- +<!-- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. +--> + +# Flame Graphs + +[Flame Graphs](http://www.brendangregg.com/flamegraphs.html) are a visualization that effectively surfaces answers to the questions like: Review comment: ```suggestion [Flame Graphs](http://www.brendangregg.com/flamegraphs.html) are a visualization that effectively surfaces answers to questions like: ``` ########## File path: docs/content/docs/ops/debugging/flame_graphs.md ########## @@ -0,0 +1,83 @@ +--- +title: "Flame Graphs" +weight: 3 +type: docs +aliases: + - /ops/debugging/flame_graphs.html + - /ops/debugging/flame_graphs +--- +<!-- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. +--> + +# Flame Graphs + +[Flame Graphs](http://www.brendangregg.com/flamegraphs.html) are a visualization that effectively surfaces answers to the questions like: +- Which methods are currently consuming CPU resources? +- How consumption by one method compares to the others? +- Which series of calls on the stack led to executing a particular method? + +{{< img src="/fig/flame_graph_on_cpu.png" class="img-fluid" width="90%" >}} +{{% center %}} +Flame Graph +{{% /center %}} + +Flame Graphs are constructed by sampling stack traces a number of times. Each method call is presented by a bar, where the length of the bar is proportional to the number of times it is present in the samples. + +Starting with Flink 1.13, Flame Graphs are natively supported in Flink. In order to produce a Flame Graph, navigate to the job graph of a running job, select an operator of interest and in the menu to the right click on the Flame Graph tab: + +{{< img src="/fig/flame_graph_operator.png" class="img-fluid" width="90%" >}} +{{% center %}} +Operator's On-CPU Flame Graph +{{% /center %}} + +Apart from the On-CPU Flame Graphs, [Off-CPU](http://www.brendangregg.com/FlameGraphs/offcpuflamegraphs.html) and Mixed visualizations are available and can be switched between by using the selector at the top of the pane: + +{{< img src="/fig/flame_graph_selector.png" class="img-fluid" width="30%" >}} + +The Off-CPU Flame Graph visualizes blocking calls found in the samples. A distinction is made as follows: +- On-CPU: `Thread.State` in **[RUNNABLE, NEW]** +- Off-CPU: `Thread.State` in **[TIMED_WAITING, WAITING, BLOCKED]** + +{{< img src="/fig/flame_graph_off_cpu.png" class="img-fluid" width="90%" >}} +{{% center %}} +Off-CPU Flame Graph +{{% /center %}} + +Mixed mode Flame Graphs are constructed from stack traces of threads in all possible states. + +{{< img src="/fig/flame_graph_mixed.png" class="img-fluid" width="90%" >}} +{{% center %}} +Flame Graph in Mixed Mode +{{% /center %}} + +## Sampling process + +Stack traces collection happens purely within a JVM, so only method calls within the Java runtime are visible (no system calls). Review comment: ```suggestion The collection of stack traces is done purely within the JVM, so only method calls within the Java runtime are visible (no system calls). ``` ########## File path: docs/content/docs/ops/debugging/flame_graphs.md ########## @@ -0,0 +1,83 @@ +--- +title: "Flame Graphs" +weight: 3 +type: docs +aliases: + - /ops/debugging/flame_graphs.html + - /ops/debugging/flame_graphs +--- +<!-- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. +--> + +# Flame Graphs + +[Flame Graphs](http://www.brendangregg.com/flamegraphs.html) are a visualization that effectively surfaces answers to the questions like: +- Which methods are currently consuming CPU resources? +- How consumption by one method compares to the others? +- Which series of calls on the stack led to executing a particular method? + +{{< img src="/fig/flame_graph_on_cpu.png" class="img-fluid" width="90%" >}} +{{% center %}} +Flame Graph +{{% /center %}} + +Flame Graphs are constructed by sampling stack traces a number of times. Each method call is presented by a bar, where the length of the bar is proportional to the number of times it is present in the samples. + +Starting with Flink 1.13, Flame Graphs are natively supported in Flink. In order to produce a Flame Graph, navigate to the job graph of a running job, select an operator of interest and in the menu to the right click on the Flame Graph tab: + +{{< img src="/fig/flame_graph_operator.png" class="img-fluid" width="90%" >}} +{{% center %}} +Operator's On-CPU Flame Graph +{{% /center %}} + +Apart from the On-CPU Flame Graphs, [Off-CPU](http://www.brendangregg.com/FlameGraphs/offcpuflamegraphs.html) and Mixed visualizations are available and can be switched between by using the selector at the top of the pane: + +{{< img src="/fig/flame_graph_selector.png" class="img-fluid" width="30%" >}} + +The Off-CPU Flame Graph visualizes blocking calls found in the samples. A distinction is made as follows: +- On-CPU: `Thread.State` in **[RUNNABLE, NEW]** +- Off-CPU: `Thread.State` in **[TIMED_WAITING, WAITING, BLOCKED]** + +{{< img src="/fig/flame_graph_off_cpu.png" class="img-fluid" width="90%" >}} +{{% center %}} +Off-CPU Flame Graph +{{% /center %}} + +Mixed mode Flame Graphs are constructed from stack traces of threads in all possible states. + +{{< img src="/fig/flame_graph_mixed.png" class="img-fluid" width="90%" >}} +{{% center %}} +Flame Graph in Mixed Mode +{{% /center %}} + +## Sampling process + +Stack traces collection happens purely within a JVM, so only method calls within the Java runtime are visible (no system calls). + +Flame Graph construction is performed at the level of an individual [operator]({{< ref "docs/concepts/glossary" >}}#operator), i.e. all [task]({{< ref "docs/concepts/glossary" >}}#task) threads of that operator are sampled in parallel and their stack traces are combined. + + + +{{< hint info >}} +**Note:** +Stack trace samples from all threads of an operator are combined together. If a method call consumes 100% of resources in one of the parallel tasks but none in the others, the bottleneck might be obcured by averaging out. Review comment: ```suggestion Stack trace samples from all threads of an operator are combined together. If a method call consumes 100% of the resources in one of the parallel tasks but none in the others, the bottleneck might be obscured by being averaged out. ``` ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
