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Bug 953 - Fix prefetches in 3px4 product kernel
Summary: Fix prefetches in 3px4 product kernel
Alias: None
Product: Eigen
Classification: Unclassified
Component: Core - matrix products (show other bugs)
Version: unspecified
Hardware: ARM - NEON Android
: Normal Unknown
Assignee: Nobody
Depends on:
Blocks: 937
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Reported: 2015-02-12 23:17 UTC by Benoit Jacob
Modified: 2019-12-04 14:13 UTC (History)
3 users (show)

fix prefetches (2.15 KB, patch)
2015-02-12 23:17 UTC, Benoit Jacob
gael.guennebaud: review+
Details | Diff

Description Benoit Jacob 2015-02-12 23:17:21 UTC
Created attachment 543 [details]
fix prefetches

On ARM, prefetches are vital for good performance. If I remove them, products typically go twice slower!

Current prefetches aren't optimal. This patch fixes the 3px4 kernel, which is what is used for floats on ARM. It's both what makes sense given the access patterns, and what actually runs fastest of all the prefetching patterns that I tried. It's a > 10% speedup on both a nexus 4 and a nexus 5. It also unblocks better understanding cache tuning.
Comment 1 Gael Guennebaud 2015-02-13 18:49:08 UTC
Comment on attachment 543 [details]
fix prefetches

Fine to me.
Comment 3 Nobody 2019-12-04 14:13:21 UTC
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