Make some Allocation Decider Code a Little More JIT Aware (#62275) #64444
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) When investigating our code cache usage for another issue I ran into this. This PR just fixes a few spots and there's many more. The current way we compute the decisions often creates much larger than necessary methods because the compiler has no efficient way of optimizing away things like using CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.getKey() as an explain parameter that do allocations (but whose results are thrown away immediately if debug is off). As a result e.g. the max retry allocation decider's canAllocate compiles into an 18kb method before and into a 2kb method after this change (at C1 L3). I think if we're a little more mindful of the JIT here we can get some measurable speedups out of the allocation deciders logic. Plus, this kind of change saves quite a few in allocations in isolation as well which is always nice on a hot CS thread I suppose.
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When investigating our code cache usage for another issue I ran into this. This PR just fixes a few spots and there's many more. The current way we compute the decisions often creates much larger than necessary methods because the compiler has no efficient way of optimizing away things like using CLUSTER_ROUTING_ALLOCATION_AWARENESS_ATTRIBUTE_SETTING.getKey() as an explain parameter that do allocations (but whose results are thrown away immediately if debug is off).
As a result e.g. the max retry allocation decider's canAllocate compiles into an 18kb method before and into a 2kb method after this change (at C1 L3). I think if we're a little more mindful of the JIT here we can get some measurable speedups out of the allocation deciders logic. Plus, this kind of change saves quite a few in allocations in isolation as well which is always nice on a hot CS thread I suppose.
backport of #62275