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19 lines
1.1 KiB
Markdown
19 lines
1.1 KiB
Markdown
### 🔀 [#429](https://github.com/ikawrakow/ik_llama.cpp/pull/429) - Option to enable or disable the CPU FA kernels
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| **Author** | `ikawrakow` |
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| :--- | :--- |
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| **State** | ❌ **Closed** |
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| **Created** | 2025-05-17 |
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| **Updated** | 2025-05-17 |
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---
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#### Description
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The compilation of `iqk_mul_mat.cpp` takes extremely long - currently 2m22s on my Ryzen-7950X CPU, with some users reporting times in the range of 30 minutes on an Antroid phone using Termux . This is to a large extent due to the Flash Attention (FA) kernels. Hence, this PR adds a `cmake` option to enable or disable the CPU FA kernels. It is set on by default, and can be changed using
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```
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cmake -DGGML_IQK_FLASH_ATTENTION=OFF ...
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```
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Setting it to off reduces compilation time of `iqk_mul_mat.cpp` to 25 seconds on the Ryzen-7950 CPU, so a speedup of 5.7X. Hopefully this will make it easier to build `ik_llama.cpp` on an Android phone.
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If `GGML_IQK_FLASH_ATTENTION` is set to `OFF`, FA is still available but will be computed using the `ggml` implementation, which is very slow on any CPU I have tried. |