Memory access pattern: Difference between revisions

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A [[Scatter (vector addressing)|scatter]] memory access pattern combines sequential reads with indexed/random addressing for writes.
<ref name="gpu gems2">{{cite web|title=gpgpu scatter vs gather|url=http://http.developer.nvidia.com/GPUGems2/gpugems2_chapter31.html}}</ref>
Compared to [[#GATHER|'gather]], It may place less load on a cache hierarchy since a [[processing element]] may dispatch writes in a 'fire and forget' manner (bypassing a cache altogether), whilst using predicatble prefetching (or even DMA) for it's source data.

However, it may be harder to parallelise since there is no guarantee the writes do not interact.,<ref name="gpu gems"/> and many systems are still designed assuming that a hardware cache will coalesce many small writes into larger ones.
 
In the past, [[forward texture mapping]] attempted to handle the randomness with 'writes', whilst sequentially reading source texture information.