Trait ExpertSource

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pub trait ExpertSource: Sync {
    // Required methods
    fn slot_layout(&self) -> SlotLayout;
    fn num_experts(&self) -> usize;
    fn read_expert(&self, layer: u32, expert: u32, dst: &mut [u8]) -> Result<()>;

    // Provided methods
    fn read_expert_range(
        &self,
        layer: u32,
        expert: u32,
        off: usize,
        dst: &mut [u8],
    ) -> Result<()> { ... }
    fn direct_segments(
        &self,
        layer: u32,
        expert: u32,
    ) -> Result<Option<Vec<DirectSeg>>> { ... }
    fn direct_file(&self, shard: usize) -> Option<&File> { ... }
}

Expand description

Anything the LRU can fill a slot from. The on-disk map implements it; the unit tests implement it in memory.

Required Methods§

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fn slot_layout(&self) -> SlotLayout

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fn num_experts(&self) -> usize

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fn read_expert(&self, layer: u32, expert: u32, dst: &mut [u8]) -> Result<()>

Fill dst (exactly slot_layout().bytes long) with expert expert of layer layer, in slot layout.

Provided Methods§

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fn read_expert_range( &self, layer: u32, expert: u32, off: usize, dst: &mut [u8], ) -> Result<()>

Fill dst with bytes off..off + dst.len() of the expert’s slot image, so one miss can be read by several threads at once. The default reads the whole expert into scratch; the on-disk map seeks.

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fn direct_segments( &self, layer: u32, expert: u32, ) -> Result<Option<Vec<DirectSeg>>>

The expert’s slot image as file ranges for O_DIRECT reads, or None when this source has no direct descriptor (the default): the staged miss path then reads through read_expert_range.

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