20% increase in transaction times when used in production about coverband HOT 4 CLOSED

Hi @DChalcraft. I haven't used coverband in a while but 20% seems like a lot to me. Coverband relies on ruby's standard library code coverage which is pretty fast and shouldn't have that much overhead. Coverband also needs to write data to redis which should also be quite fast.

I think it would be interesting to dig in and see what's happening in your case. If you can replicate the issue in development then I think we are in a good position to track this down using a flame graph. Here's a library that I have used.

https://github.com/SamSaffron/flamegraph

As mentioned in the readme you could also use rack-mini-profiler which is a convenience library built on top of flamegraph and allows for generating the flamegraph directly in your browser with a request parameter.

In the end, you really just need to execute a code sample with coverband and without and compare the two flamegraphs. Just make sure that you've reproduced the issue in dev with that code sample before bringing in flamegraphs.

Hope that helps!

from coverband.

yeah, I haven't seen anything that drastic in terms of performance impact. If you have more info on the size of project, rails version, ruby version, coverband version, machine memory / CPU, etc that might help.

If you haven't adjusted any of the various toggles like reporting wiggle etc it would be worth trying those out.

from coverband.

Did you try anything else? If you have any other info I can try to look...

• rails / ruby versions
• number of files
• server: puma, unicorn, etc?
• coverband configuration file / options?

Let me know if you are doing any other investigation or want some specific help or I will close this out.

from coverband.

We've had to move onto other things for now so haven't had a chance to come back to this. If we return in the future I will post an update. Thanks for the help!

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