CultureInfo creation is slower on Linux by 0.1 millisecond compared to Windows.

[DerFnoeh]

Description

When creating a CultureInfo-Object for decimal-Parsing Linux is over 40 times slower compared to windows environments.

The differences can be easily observed by running the same program once inside a windows- and once inside a linux-container.

Example project

Build&Run the dockerfile. It will output the total time in milliseconds.
https://github.com/DerFnoeh/PerformanceDifferencesCultureInfo

Configuration

Laptop running windows and linux container

• .NET6
• DockerDesktop on Windows 10 WSL2
• Image-Base: mcr.microsoft.com/dotnet/aspnet:6.0
• VS2022
• 32GB RAM
• i7 10750H

Performance was also affected on:

• Native Ubuntu 20.04, AMD Ryzen x64
• Azure AppService (Linux-Container)
• Various other laptops with similiar setups

Regression?

Similar results in .NET5

Data

Benchmark Result

300ms on Windows
13000ms on Linux

Trace-Data of slow-execution:

Most CPU Time was spent in the following methods.

Function Name	Total CPU [unit, %]	Self CPU [unit, %]	Module
| - System.Globalization.CultureInfo.get_NumberFormat()	453550 (60,22 %)	4 (0,00 %)	System.Private.CoreLib.dll
| - System.Decimal.TryParse(class System.String,value class System.Globalization.NumberStyles,class System.IFormatProvider,value class System.Decimal&)	453378 (60,20 %)	3 (0,00 %)	System.Private.CoreLib.dll
| - System.Globalization.NumberFormatInfo..ctor(class System.Globalization.CultureData)	453301 (60,19 %)	2 (0,00 %)	System.Private.CoreLib.dll
| - System.Globalization.CultureData.GetNFIValues(class System.Globalization.NumberFormatInfo)	453261 (60,18 %)	19 (0,00 %)	System.Private.CoreLib.dll

Analysis

I spent the whole day investigating our larger-code-base to isolate this issue. Unfortunately I am not versed in the deeper details of OS-interfacing and can't provide any further insights.

Workaround

Instead of instantiating CultureInfo every time it is needed, we setup a static readonly variable for it. This removed all performance drawbacks.

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Issue Details

---

Description

When creating a CultureInfo-Object for decimal-Parsing Linux is over 40 times slower compared to windows environments.

The differences can be easily observed by running the same program once inside a windows- and once inside a linux-container.

Example project: https://github.com/DerFnoeh/PerformanceDifferencesCultureInfo

Configuration

Laptop running windows and linux container

• .NET6
• DockerDesktop on Windows 10 WSL2
• Image-Base: mcr.microsoft.com/dotnet/aspnet:6.0
• VS2022
• 32GB RAM
• i7 10750H

Bug also appeared during troubleshooting on:

• Native Ubuntu 20.04, AMD Ryzen x64
• Azure AppService (Linux-Container)
• Various other laptops with similiar setups

Regression?

Similar results in .NET5

Data

Benchmark Result

300ms on Windows
13000ms on Linux

Trace-Data of slow-execution:

Most CPU Time was spent in the following methods.

Function Name	Total CPU [unit, %]	Self CPU [unit, %]	Module
| - System.Globalization.CultureInfo.get_NumberFormat()	453550 (60,22 %)	4 (0,00 %)	System.Private.CoreLib.dll
| - System.Decimal.TryParse(class System.String,value class System.Globalization.NumberStyles,class System.IFormatProvider,value class System.Decimal&)	453378 (60,20 %)	3 (0,00 %)	System.Private.CoreLib.dll
| - System.Globalization.NumberFormatInfo..ctor(class System.Globalization.CultureData)	453301 (60,19 %)	2 (0,00 %)	System.Private.CoreLib.dll
| - System.Globalization.CultureData.GetNFIValues(class System.Globalization.NumberFormatInfo)	453261 (60,18 %)	19 (0,00 %)	System.Private.CoreLib.dll

Analysis

I spent the whole day investigating our larger-code-base to isolate this issue. Unfortunately I am not versed in the deeper details of OS-integration and can't provide any further insights.

Workaround

Instead of instantiating CultureInfo every time it is needed, we setup a static readonly variable for it. This removed all performance drawbacks.

Author:	DerFnoeh
Assignees:	-
Labels:	area-System.Globalization, tenet-performance, untriaged
Milestone:	-

[EgorBo]

I wonder if we should cache ICU info (e.g. GetNFIValues) globally per culture id so all new instances of CultureInfo will be accessing that dictionary instead of asking ICU all the time - it is unlikely a typical app will trigger GetNFIValues for all the available cultures, right?

[Clockwork-Muse]

There already exists a mechanism to get cached cultures: CultureInfo.GetCultureInfo(...). Note this will return "unmodified" cultures (at least on Windows - see the remarks on the constructor documentation), but this may not be an issue in most cases.

[tarekgh]

@DerFnoeh as @Clockwork-Muse indicated, you should use CultureInfo.GetCultureInfo() which already caching the created read-only instance.

Also, your test is measuring the creation of 100,000 creation instance. Does the perf numbers you mentioned are for the whole 100,000 creation? If this is correct, does that mean the difference you are seeing is around 0.1 ms per creation?

Also, if you are using .NET 6.0, we should be executing the same code on Windows and Linux.

[EgorBo]

you should use CultureInfo.GetCultureInfo() which already caching the created read-only instance.

Honestly speaking, I found myself always using new CultureInfo(...) pattern - can we construct it using cached data somehow?

[tarekgh]

Honestly speaking, I found myself always using new CultureInfo(...) pattern - can we construct it using cached data somehow?

The culture created with new CultureInfo() will be read-write. The issue is not during the creation itself; the issue is when asking for properties after creation (like NumberFormat for instance and Ensure support users override too which is picked up from the system settings too. It is possible to try to optimize but I am not sure it is worth the complication we'll add to the code while there are simpler solutions.

[EgorBo]

Can we then add a roslyn analyzer suggesting CultureInfo.GetCultureInfo() API over new CultureInfo()?

[tarekgh]

Can we then add a roslyn analyzer suggesting CultureInfo.GetCultureInfo() API over new CultureInfo()?

Will be hard to do that because it depends on the user scenario which hard to detect. Anyone wants read-write culture or need to pick the user override they will need to use new CultureInfo. It will be hard to have the analyzers detect the intention of the creation. We are educating the users as much as we can, especially when we spot patterns that can cause perf issues.

[ShreyasJejurkar]

Can we then add a roslyn analyzer suggesting CultureInfo.GetCultureInfo() API over new CultureInfo()?

Docs already say about this one. But the analyzer will be helpful as well.

https://docs.microsoft.com/en-us/dotnet/api/system.globalization.cultureinfo.getcultureinfo?view=net-6.0