Developers observe more efficient expiration checks within MemoryCache

[jeffhandley]

Previously, we avoided using a Timer for checking cache expiration because such usage would prevent recycling of idle services; this constraint no longer exists. With a Timer-based expiration check, MemoryCache APIs will no longer incur the cost of checking expiration time to spawn a background task to remove expired items. This will yield a ~10% RPS performance gain. See #45842 for more performance benchmark details and conversation.

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Issue Details

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Previously, we avoided using a Timer for checking cache expiration because such usage would prevent recycling of idle services; this constraint no longer exists. With a Timer-based expiration check, MemoryCache APIs will no longer incur the cost of checking expiration time to spawn a background task to remove expired items. This will yield a ~10% RPS performance gain. See #45842 for more performance benchmark details and conversation.

Author:	jeffhandley
Assignees:	adamsitnik
Labels:	Bottom Up Work, User Story, area-Extensions-Caching, tenet-performance
Milestone:	6.0.0

[Tratcher]

Previously, we avoided using a Timer for checking cache expiration because such usage would prevent recycling of idle services; this constraint no longer exists.

Why does that constraint no longer exist? ASP.NET Core does not want timers firing on idle web services. @davidfowl

[davidfowl]

We do have timers firing on idle web services. All the time.