<div dir="ltr">thanks nyall</div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature" data-smartmail="gmail_signature">Luigi Pirelli<br><br>**************************************************************************************************<br>* LinkedIn: <a href="https://www.linkedin.com/in/luigipirelli" target="_blank">https://www.linkedin.com/in/luigipirelli</a><br>* Stackexchange: <a href="http://gis.stackexchange.com/users/19667/luigi-pirelli" target="_blank">http://gis.stackexchange.com/users/19667/luigi-pirelli</a><br>* GitHub: <a href="https://github.com/luipir" target="_blank">https://github.com/luipir</a><br>* Mastering QGIS 2nd Edition:<br>* <a href="https://www.packtpub.com/big-data-and-business-intelligence/mastering-qgis-second-edition" target="_blank">https://www.packtpub.com/big-data-and-business-intelligence/mastering-qgis-second-edition</a><br>* Hire me: <a href="http://goo.gl/BYRQKg" target="_blank">http://goo.gl/BYRQKg</a><br>**************************************************************************************************</div></div>
<br><div class="gmail_quote">On 8 June 2018 at 01:38, Nyall Dawson <span dir="ltr"><<a href="mailto:nyall.dawson@gmail.com" target="_blank">nyall.dawson@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi all,<br>
<br>
Thought I'd give a bit of a "heads-up" regarding a tool I've been<br>
using a lot recently to find performance bottlenecks in QGIS code.<br>
<br>
The tool is hotspot - <a href="https://github.com/KDAB/hotspot" rel="noreferrer" target="_blank">https://github.com/KDAB/<wbr>hotspot</a> . It's a<br>
graphical frontend to the kernel perf tool (so linux only). What makes<br>
it really easy to use is the different views it provides to the perf<br>
reports. I've especially found the "flamegraph" view to be very<br>
helpful at tracking down bottlenecks.<br>
<br>
To use it, you launch QGIS and get ready to run the process you want<br>
to profile. Then from hotspot, you run the File - Record Data command,<br>
and attach to the running QGIS process. Flick back to QGIS, do some<br>
stuff, and return to hotspot and Stop Recording then View Results...<br>
and fingers crossed, you'll find some nice and easy bottlenecks to<br>
fix.<br>
<br>
I've tried other tools like this in the past, but found hotspot is the<br>
easiest to to use because it doesn't require any compilation changes,<br>
you can attach to already running applications, and because the<br>
supplied views are very helpful.<br>
<br>
I think the server team especially may find this beneficial during<br>
their current hunt on server performance regressions!<br>
<br>
Nyall<br>
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