Maysam Yabandeh 54d94e9c2c PinnableSlice ... Summary: Currently the point lookup values are copied to a string provided by the user. This incures an extra memcpy cost. This patch allows doing point lookup via a PinnableSlice which pins the source memory location (instead of copying their content) and releases them after the content is consumed by the user. The old API of Get(string) is translated to the new API underneath. Here is the summary for improvements: 1. value 100 byte: 1.8% regular, 1.2% merge values 2. value 1k byte: 11.5% regular, 7.5% merge values 3. value 10k byte: 26% regular, 29.9% merge values The improvement for merge could be more if we extend this approach to pin the merge output and delay the full merge operation until the user actually needs it. We have put that for future work. PS: Sometimes we observe a small decrease in performance when switching from t5452014 to this patch but with the old Get(string) API. The difference is a little and could be noise. More importantly it is safely cancelled Closes https://github.com/facebook/rocksdb/pull/1732 Differential Revision: D4374613 Pulled By: maysamyabandeh fbshipit-source-id: a077f1a		2017-01-08 13:54:13 -08:00
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rocksdb	PinnableSlice	2017-01-08 13:54:13 -08:00