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The prefix cache is a resource shared by all users. This is basically a tragedy of the commons.
by kakugawa 2mo ago
The prefix cache is a resource shared by all users. This is basically a tragedy of the commons.
- fearmerchant 2mo agoIf true, I suspect Anthropic will begin suspending accounts that use it.
- dannyw 2mo agoI highly doubt that. Keeping your cache warm is a good thing, caching saves compute and electricity. Cached input is cheap for a reason, it is in everyone’s mutual interests to maximise cache hit rates.
- OccamsMirror 2mo agoIf that was true then Anthropic would have built this functionality in themselves.
- brookst 2mo agoThey did. On any long running query with large context, tell Claude “give me a status report every 4 minutes to keep the cache warm”. It’s entirely happy to oblige and usually says “good idea, that will keep costs down”
- dannyw 2mo agoCompute is also a resource shared by all users. When your prompt isn’t cached, your input needs to go through prefill; which is compute-bound. The cache is discounted for a reason. They WANT you to use it.
- searealist 2mo agoThey could always just extend the cache timeout beyond 5 minutes themselves. They don't do that because it is an expensive resource and there is a trade-off bewteen saving computation and reserving VRAM. Running a tool like this will force them to do one of the following: 1) Start charging for VRAM reservations. 2) Charge _other_ customers more. 3) Eat the cost themselves.
- dannyw 2mo agoThey charge you for cache writes already. There's a price assigned to it. Even if you're on subscription, it counts against your usage (very easy to observe with a big cache miss). Anthropic (and now OpenAI too for 5.6) prompt caching is not free.
- searealist 2mo agoHolding your cache in VRAM for 5 minutes or 3 hours have very different costs to them. "They already charge me to park my car, why can't I leave it there for a year for the same price as 1 week?"
- brookst 2mo agoSo why is it 5 minutes at both peak and off peak hours? If they can guarantee 5 minutes at peak hours for everyone, why is it only 5 minutes at off peak? I don’t think your understanding works.