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Questions tagged [flamegraph]

Flame graphs are a visualization of profiled software, allowing the most frequent code-paths to be identified quickly and accurately — Brendan Gregg

Flame graphs are a visualization of profiled software, allowing the most frequent code-paths to be identified quickly and accurately.

enter image description here

The x-axis shows the stack profile population, sorted alphabetically (it is not the passage of time), and the y-axis shows stack depth. Each rectangle represents a stack frame. The wider a frame is, the more often it was present in the stacks. The top edge shows what is on-CPU, and beneath it is its ancestry. The colors are usually not significant, picked randomly to differentiate frames.

This visualization is fully introduced and explained in the CPU Flame Graphs page, and in Brendan Gregg presentation.

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How does linux's perf utility understand stack traces?

Linux's perf utility is famously used by Brendan Gregg to generate flamegraphs for c/c++, jvm code, nodejs code, etc. Does the Linux kernel natively understand stack traces? Where can I read more about how a tool is able to introspect into stack…
Shahbaz
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How to interpret gaps in chrome flame charts

I'm trying to better understand how to interpret chrome flame charts. In the below chart _changeHandler is shown as four distinct blocks. However I know for fact that it's only being called once. I saw a similar question here, which claims this…
Willem D'Haeseleer
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Chrome Timeline does not show all calls on a flame chart

While using Google Chrome Timeline feature I have noticed a strange thing. On my PC in a workplace flame chart is very flat, showing only 1-2 function calls deep. My first thought was: "Well, that is the way this thing works". But when I opened the…
aadam
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How to avoid truncated stack traces with Java Flight Recorder

I am using Oracle Java Flight Recorder to collect stack trace samples of a Java application. Theses stack traces allows me to eventually produce a CPU Flamegraph. My issue is that stack traces deeper than 64 frames are truncated by Java Flight…
Clément MATHIEU
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Why does the Java flight recorder take too few samples?

We have a bad performing application and therefore we used the flight recorder's method profiling to see where the time is spent. It's basically working, but the number of taken samples is way below 100 for a minute of recording. (using the…
Kai Giebeler
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Profiling of PyTorch Custom Dataset for Dataloader

I implemented a custom PyTorch Dataset for my project's Dataloader to use. However, it is running slower than expected so profiling was chosen to troubleshoot the bottleneck. Looked into vprof but I am unsure of the function to be profiled if I am…
Athena Wisdom
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Construct flame graph from trie

I have some stats in a trie which is generated periodically. I want to generate flame graphs on the difference between two tries. How do I do that? t = pygtrie.StringTrie(separator=os.path.sep) for dirpath, unused_dirnames, filenames in…
Gyanendra Singh
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How to find out which hook has changed with the help of hook number/index displayed in FlameGraph

I'm working on a react application and want to improve the performance. I was using the Profiler to see the components painted on each render and also FlameGraph to find out which one is taking long time. In the Flamegraph it shows the detailed…
praveen guda
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Generate Flame Graph from JFR dump with IntelliJ IDEA

IDEA generates those neat flame graphs when using "Run with Java Flight Recorder". While I know of external tools capable of this, is it possible to generate those flame graphs from existing jfr dumps with IDEA?
Nick Russler
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A problem about chrome devltools javascript profiler flame graph, aggregated time is smaller than total time

aggregated time and total time are underlined in the picture. devtool flame graph what's the meaning of this circumstance?
weisiwu
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Errors when generating mixed mode Flame Graphs

I'm trying to generate some mixed mode flame graphs on a Linux machine (CentOS 7) and running into some issues. I'm following instructions from this link: https://www.slideshare.net/brendangregg/java-performance-analysis-on-linux-with-flame-graphs…
pree
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How to create a flamegraph of Bash script running time?

I am trying to profile a slow bash script. I have seen a few methods to do so in this question, but they all give absolute timings, or relative from one line to the next. I would like to have timings per command / stack, to be able to dig in. A…
Ciprian Tomoiagă
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Perf collection on kubernetes pods

I am trying to find performance bottlenecks by using the perf tool on a kubernetes pod. I have already set the following on the instance hosting the pod: "kernel.kptr_restrict" = "0" "kernel.perf_event_paranoid" = "0" However, I have to…
Hadi
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How can you get frame-pointer perf call stacks/flamegraphs involving the C++ standard library?

I like the fp method for collecting call stacks with perf record since it's lightweight and less complex than dwarf. However, when I look at the call stacks/flamegraphs I get when a program uses the C++ standard library, they are not correct. Here…
nnnmmm
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Does Firefox allow profiling JS apps using "aggregated" flame charts?

Firefox Developer Tools support flame charts, but it seems time is used as X-axis: In the Flame Chart view itself, along the X-axis is time. The screenshot above covers the period from 1435ms to a little past 1465ms. Along the Y-axis are the…
johndodo
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