String.Concat Slow in .NET 4.5 by Ehrys

Active

Type:	Bug
ID:	780770
Opened:	3/6/2013 2:40:20 AM
Access Restriction:	Public

Workaround(s)

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User(s) can reproduce this bug

When analysing the performance of different String manipulation methods, String.Concat came out drastically slower than the same code compiled for .NET 3.5

Please see this article I wrote: http://www.daniweb.com/software-development/csharp/code/448050/performance-of-string-operations

It seems to be the way that the IL is generated. It is subtly different to the same code compiled for .NET 3.5. Why does the same level of optimisation no longer apply in 4.5?

Details (expand)

.NET Framework 4.5

See code written in the article. Compile and run using standard settings in release mode.

English

Windows 7

English

Actual results are that operations using String.Concat are incredibly slow compared to other ways of performing concatenation (StringBuilder and new String)

String.Concat should not exhibit the drastic performance drop compared to the other operations.

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Posted by Microsoft on 3/27/2013 at 11:12 AM

Thank you for your feedback. We are not going to be able to address this issue in our next release due to other priorities.

You can workaround the issue by casting the string to object.

Regards,
Immo Landwerth
.NET Framework team

Posted by Microsoft on 3/6/2013 at 9:41 PM

Thanks for your feedback.

We are rerouting this issue to the appropriate group within the Visual Studio Product Team for triage and resolution. These specialized experts will follow-up with your issue.

Posted by Microsoft on 3/6/2013 at 2:50 AM

Thank you for your feedback, we are currently reviewing the issue you have submitted. If this issue is urgent, please contact support directly(http://support.microsoft.com)

Microsoft