Add a specialization of read_exact for Cursor. #46485
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The read_exact implementation for &[u8] is optimized and usually allows LLVM to reduce a read_exact call for small numbers of bytes to a bounds check and a register load instead of a generic memcpy. On a workload I have that decompresses, deserializes (via bincode), and processes some data, this leads to a 40% speedup by essentially eliminating the deserialization overhead entirely.
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Cc @Manishearth |
kennytm
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@bors r+ Seems innocuous; shouldn't change any behavior. |
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📌 Commit 02c1862 has been approved by |
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Add a specialization of read_exact for Cursor. The read_exact implementation for &[u8] is optimized and usually allows LLVM to reduce a read_exact call for small numbers of bytes to a bounds check and a register load instead of a generic memcpy. On a workload I have that decompresses, deserializes (via bincode), and processes some data, this leads to a 40% speedup by essentially eliminating the deserialization overhead entirely.
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☀️ Test successful - status-appveyor, status-travis |
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The read_exact implementation for &[u8] is optimized and usually allows LLVM to reduce a read_exact call for small numbers of bytes to a bounds check and a register load instead of a generic memcpy. On a workload I have that decompresses, deserializes (via bincode), and processes some data, this leads to a 40% speedup by essentially eliminating the deserialization overhead entirely.