from Hacker News

Hotspot: Linux `perf` GUI for performance analysis

by jez on 5/19/25, 9:33 PM with 17 comments

  • by gue-ni on 5/22/25, 8:29 AM

    Fun fact: firefox also supports loading 'perf' reports: https://profiler.firefox.com/

  • by ognarb on 5/22/25, 9:50 AM

    From the same author, Heaptrack to investigate memory usage is also very helpful: https://invent.kde.org/sdk/heaptrack/

  • by fransje26 on 5/22/25, 8:56 AM

    Great tool that has been really helpful in helping me find unexpected bottlenecks in the codebases I've been working on.

    It's easy to use, and pairs beautifully with the unintrusive perf tool, which makes the combination a joy to use.

    And, if combined with a codebase opened in QtCreator, you can click on a hotspot in the flamegraph, and it will bring you automagically to the correct file and line in QtCreator, without any explicit linking required between the two programs. I discovered that feature accidentally, and the fact that it just worked seamlessly really impressed me. (Tested on a Debian-based Linux).

    A big thanks to KDAB for making this tool available to us!

  • by directmusic on 5/22/25, 11:51 AM

    I primarily do macOS development work and use Instruments for profiling, but have been working on Linux a lot lately and Hotspot has been pulled out a lot over the last few weeks. Highly recommended.

  • by wizzledonker on 5/22/25, 1:24 PM

    This is a fantastic tool and I recommend it! I use it every day to recursively solve bottlenecks in our code base.

  • by pjmlp on 5/22/25, 9:33 AM

    Nice tool, thanks for the heads up.

  • by drewg123 on 5/22/25, 5:44 PM

    I'm on FreeBSD, so its a lot of overhead to check myself: But, does this have a source view like Vtune, that can attribute cycles / cache misses / etc, to a line of code? I see it has an assembly view..

  • by dustbunny on 5/22/25, 8:00 PM

    I couldn't figure out how to use hotspot. I used speedscope instead: https://www.speedscope.app/

    Maybe I should check out hotspot again.

  • by grandinj on 5/22/25, 1:56 PM

    Wonderful tool. Has been incredibly useful in optimising LibreOffice.