[core] use StringComparer for Dictionary/HashSet #14900
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Context: dotnet#12130 Context: https://github.com/angelru/CvSlowJittering When profiling the above customer app while scrolling, 4% of the time is spent doing dictionary lookups: (4.0%) System.Private.CoreLib!System.Collections.Generic.Dictionary<TKey_REF,TValue_REF>.FindValue(TKey_REF) Observing the call stack, some of these are coming from culture-aware string lookups in MAUI: * `microsoft.maui!Microsoft.Maui.PropertyMapper.GetProperty(string)` * `microsoft.maui!Microsoft.Maui.WeakEventManager.AddEventHandler(System.EventHandler`1<TEventArgs_REF>,string)` * `microsoft.maui!Microsoft.Maui.CommandMapper.GetCommand(string)` Which show up as a mixture of `string` comparers: (0.98%) System.Private.CoreLib!System.Collections.Generic.NonRandomizedStringEqualityComparer.OrdinalComparer.GetHashCode(string) (0.71%) System.Private.CoreLib!System.String.GetNonRandomizedHashCode() (0.31%) System.Private.CoreLib!System.Collections.Generic.NonRandomizedStringEqualityComparer.OrdinalComparer.Equals(string,stri (0.01%) System.Private.CoreLib!System.Collections.Generic.NonRandomizedStringEqualityComparer.GetStringComparer(object) In cases of `Dictionary<string, TValue>` or `HashSet<string>`, we can use `StringComparer.Ordinal` for faster dictionary lookups. Unfortunately, there is no code analyzer for this: dotnet/runtime#52399 So, I manually went through the codebase and found all the places. I now only see the *fast* string comparers in this sample: (1.3%) System.Private.CoreLib!System.Collections.Generic.NonRandomizedStringEqualityComparer.OrdinalComparer.GetHashCode(string) (0.35%) System.Private.CoreLib!System.Collections.Generic.NonRandomizedStringEqualityComparer.OrdinalComparer.Equals(string,stri Which is about ~0.36% better than before. This should slightly improve the performance of handlers & all controls on all platforms. I also fixed `Microsoft.Maui.Graphics.Text.TextColors` to use `StringComparer.OrdinalIgnoreCase` -- and removed a `ToUpperInvariant()` call.
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Maybe add a TODO comment in the editorconfig file to enforce an error whenever such a code analyzer shows up, and link that open issue. |
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@symbiogenesis since dotnet/runtime#52399 was opened in 2019, I don't know when (if ever) it will be completed. Or is there a |
mattleibow
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May 3, 2023
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Context: #12130
Context: https://github.com/angelru/CvSlowJittering
When profiling the above customer app while scrolling, 4% of the time is spent doing dictionary lookups:
Observing the call stack, some of these are coming from culture-aware string lookups in MAUI:
microsoft.maui!Microsoft.Maui.PropertyMapper.GetProperty(string)microsoft.maui!Microsoft.Maui.WeakEventManager.AddEventHandler(System.EventHandler1<TEventArgs_REF>,string)`microsoft.maui!Microsoft.Maui.CommandMapper.GetCommand(string)Which show up as a mixture of
stringcomparers:In cases of
Dictionary<string, TValue>orHashSet<string>, we can useStringComparer.Ordinalfor faster dictionary lookups.Unfortunately, there is no code analyzer for this:
dotnet/runtime#52399
So, I manually went through the codebase and found all the places.
I now only see the fast string comparers in this sample:
Which is about ~0.36% better than before.
This should slightly improve the performance of handlers & all controls on all platforms.
I also fixed
Microsoft.Maui.Graphics.Text.TextColorsto useStringComparer.OrdinalIgnoreCase-- and removed aToUpperInvariant()call.