[LOG4NET-585] log4net became very slow with caller location information after Windows 10 Fall Creators Update (1709)

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Information Provided
• Affects Version/s: 2.0.8
• Component/s: Core
• Labels: performance windows
• Environment: Windows 10 Pro 64-Bit (1709) ; .NET Framework 4.5.2 ; Visual Studio 2015
• External issue URL: https://stackoverflow.com/questions/47760546/log4net-became-very-slow-with-caller-location-information-after-windows-10-fall
• Assignee: Dominik Psenner
• Reporter: Tobias Bindel
• Created: 12/Dec/17 09:56
• Updated: 17/Jan/18 16:12
• Resolved: 12/Dec/17 17:03

Description

The documentation of log4net points out that the logging of caller location information can be very slow and shouldn't be used unless the performance of the software is not affected. And until the Windows 10 Fall Creators Update this was the case.

But after the Windows update (1709) the performance with caller location information like %C %M %L is about 100 times slower than without. The following results are based on the simple Visual Studio project attached to this issue.

Results before Windows update (1709)

without %C %M %L: Logging of 1000 iterations took: 18 ms.
with %C %M %L: Logging of 1000 iterations took: 81 ms.

Results after Windows update (1709)

without %C %M %L: Logging of 1000 iterations took: 14 ms.
with %C %M %L: Logging of 1000 iterations took: 1502 ms.

I hope this issue can be fixed or a workaround offered. Thanks in advance!