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Hans de Goede: Is Copilot useful for kernel patch review?
news.movim.eu / PlanetGnome • 23 June • 1 minute
Patch review is an important and useful part of the kernel development process, but it also a time-consuming part. To see if I could save some human reviewer time I've been pushing kernel patch-series to a branch on github, creating a pull-request for the branch and then assigning it to Copilot for review. The idea being that In would fix any issues Co-pilot catches before posting the series upstream saving a human reviewer from having to catch the issues.
I've done this for 5 patch-series: one , two , three , four , five , totalling 53 patches in total. click the number to see the pull-request and Copilot's reviews.
Unfortunately the results are not great on 53 patches Co-pilot had 4 low-confidence comments which were not useful and 3 normal comments. 2 of the no comments were on the power-supply fwnode series one was about spelling degrees Celcius as degrees Celsius instead which is the single valid remark. The other remark was about re-assigning a variable without freeing it first, but Copilot missed that the re-assignment was to another variable since this happened in a different scope. The third normal comment ( here ) was about as useless as they can come.
To be fair these were all patch-series written by me and then already self-reviewed and deemed ready for upstream posting before I asked Copilot to review them.
As another experiment I did one final pull-request with a couple of WIP patches to add USBIO support from Intel. Copilot generated 3 normal comments here all 3 of which are valid and one of them catches a real bug. Still given the WIP state of this case and the fact that my own review has found a whole lot more then just this, including the need for a bunch if refactoring, the results of this Copilot review are also disappointing IMHO.
Co-pilot also automatically generates summaries of the changes in the pull-requests, at a first look these look useful for e.g. a cover-letter for a patch-set but they are often full with half-truths so at a minimum these need some very careful editing / correcting before they can be used.
My personal conclusion is that running patch-sets through Copilot before posting them on the list is not worth the effort.
comments
I've done this for 5 patch-series: one , two , three , four , five , totalling 53 patches in total. click the number to see the pull-request and Copilot's reviews.
Unfortunately the results are not great on 53 patches Co-pilot had 4 low-confidence comments which were not useful and 3 normal comments. 2 of the no comments were on the power-supply fwnode series one was about spelling degrees Celcius as degrees Celsius instead which is the single valid remark. The other remark was about re-assigning a variable without freeing it first, but Copilot missed that the re-assignment was to another variable since this happened in a different scope. The third normal comment ( here ) was about as useless as they can come.
To be fair these were all patch-series written by me and then already self-reviewed and deemed ready for upstream posting before I asked Copilot to review them.
As another experiment I did one final pull-request with a couple of WIP patches to add USBIO support from Intel. Copilot generated 3 normal comments here all 3 of which are valid and one of them catches a real bug. Still given the WIP state of this case and the fact that my own review has found a whole lot more then just this, including the need for a bunch if refactoring, the results of this Copilot review are also disappointing IMHO.
Co-pilot also automatically generates summaries of the changes in the pull-requests, at a first look these look useful for e.g. a cover-letter for a patch-set but they are often full with half-truths so at a minimum these need some very careful editing / correcting before they can be used.
My personal conclusion is that running patch-sets through Copilot before posting them on the list is not worth the effort.