Large memory dependency in OrdinalCasing::ToUpper

[marek-safar]

runtime/src/libraries/System.Private.CoreLib/src/System/Globalization/OrdinalCasing.Icu.cs

Line 88 in 43bc8e8

ushort[]? casingTable = s_casingTable[pageNumber];

has a dependency on the large array which is unnecessary. The whole array is about 25k 2k and aggressively allocated in the static constructor but it needs to actually store only 32 bytes of data. Please replaced the multi-dimensional array with simple binary map (0 for existing null, 1 for s_noCasingPage).

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[tarekgh]

@marek-safar

The whole array is about 25k and aggressively allocated in the static constructor

This is not true. the whole static array size is 256 * sizeof(IntPtr) which maximum static allocation is 2K. how did you come up with the 25K?

[tarekgh]

Please replaced the multi-dimensional array with simple binary map (0 for existing null, 1 for s_noCasingPage).

This is not going to work, at runtime we allocate more dynamic tables and add to this static array.

[marek-safar]

This is not true. the whole static array size is 256 * sizeof(IntPtr) which maximum static allocation is 2K

Sorry, that was a typo, it's 2k which is still very large.

This is not going to work, at runtime we allocate more dynamic tables and add to this static array.

The existing code only replaces the null entries. I made one suggestion and there are other solutions to remove the large initialization dependency (about 1k of IL) in the code.

[tarekgh]

I'll look at that.