Notice (2018-05-24): bugzilla.xamarin.com is now in
Please join us on
Visual Studio Developer Community and in the
Mono organizations on
GitHub to continue tracking issues. Bugzilla will remain
available for reference in read-only mode. We will continue to work
on open Bugzilla bugs, copy them to the new locations
as needed for follow-up, and add the new items under Related
Our sincere thanks to everyone who has contributed on this bug
tracker over the years. Thanks also for your understanding as we
make these adjustments and improvements for the future.
Please create a new report for Bug 57277 on
Developer Community or GitHub if you have new
information to add and do not yet see a matching new report.
If the latest results still closely match this report, you can use the
In special cases on GitHub you might also want the comments:
GitHub Markdown with public comments
Created attachment 22779 [details]
Sample large XAML file that takes 5-6 seconds to compile by itself
The core XamlC task runs unusually slowly on larger files (>10 KB typically demonstrates the slowness). On a project with ~120 XAML files, this can easily lead to over a minute of XamlC task time (compared to <10s combined for all other build tasks). Updating from XF 2.3.3/Mono 4.8 to XF 2.3.4/Mono 5 improves the speed somewhat, but the compile times are still significantly slower compared to other projects that contain no XAML.
I discussed the issue with Stephane Delcroix at Xamarin and this was his response:
"On this 4yo machine (mbp13, 2013) I get consistent results with what you report: the project takes 1m01 to build.
Updating to xf 2.3.4 and mono>5, the same projects builds in 27s, of which 21s are for XamlC. I get a good uniformity in results. Changing the log verbosity or building in Release mode doesn’t skim much time (a bit more than a sec in Release vs Debug).
I then instrumented XamlC to get finer results.
1/ Assembly loading, assembly writing: around 600ms for writing, not measured reading. I’m fine with that given the size of the assembly
2/ Parsing times: 2ms for the biggest files. Could be better, maybe, but I’m fine with those results
3/ the core of XamlC takes up to 700ms for a handful of files in your solution. There’s probably something we can work on there.
I’ve looked again at your Xaml, there’s no visible abuse, and I don’t have any advice to reduce the build time for those at this time."