Avoid hitting slow map for common class descriptors #569
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When accepting `Class<?>` arguments, try to avoid hitting the slow synchronized map behind `ClassValue` for common types. The common types are gleaned from our known constant fields. We're trading a bit of class init time for higher throughput. An alternative would be to hand-write the map, which is a little more error-prone but could possibly be faster than using reflection.
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Another possible follow-on or substitute idea would be to make this map be copy-on-write, and add in entries for any class which is in the application, platform, or boot class loaders (since those will never unload anyway, they cannot leak). |
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Have you measured any diff, I don't see any in the crazybeans benchmark? Now, maybe it's not testing a scenario where this could shine? |
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I think the crazybeans paths mostly use descriptor constants now, so it might not be the best test for this. But then again maybe that shows that this change won't really help much in practice. |
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Unless someone sneaked a change into ArC that I'm not aware of, the crazybeans benchmark still uses a lot of |
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I want to ponder this a bit more and see if I can make it have a measurable performance benefit in some form. |
3 participants
When accepting
Class<?>arguments, try to avoid hitting the slow synchronized map behindClassValuefor common types. The common types are gleaned from our known constant fields. We're trading a bit of class init time for higher throughput. An alternative would be to hand-write the map, which is a little more error-prone but could possibly be faster than using reflection.