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I don't see why we can't cache more SyntaxTokens than the kinds that we are currently special casing. Currently, I see about 0.3% of allocations are creating SyntaxTokens in the Cohosting speedometer test. Going to do a test run and see what that looks like with this change.
DustinCampbell
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Sep 30, 2025
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FWIW, it'd be great if we could be smarter about caching green tokens that have known text. In Roslyn, SyntaxKind is ordered specifically to make it easy to index into an array of tokens with well-known text. Razor's SyntaxKind would need to be reordered more sensibly to allow for that. However, if that were done, we'd only need to hash the tokens that can have different text, such as StringLiteral. This would cut down on cache collisions.
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That would be nice. I do see some collisions when operating in mudblazor, but the perf numbers came back good enough that I'm not going to worry too much about that right now. |
This was referenced Oct 15, 2025
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Increase SyntaxToken cache usage to not limit the SyntaxKinds allowed in the cache.
SyntaxTokens account for about 0.4% of total allocations in the RoslynCodeAnalysisService process in the Cohosting speedometer test.
Test insertion: https://dev.azure.com/devdiv/DevDiv/_git/VS/pullrequest/675292
Allocations of SyntaxTokens decreased over 90% with this change.
Before:
After:
