Update documentation to reflect k-NN FAISS AVX512 support

_search-plugins/knn/knn-index.md

@@ -51,7 +51,7 @@ Starting with k-NN plugin version 2.16, you can use `binary` vectors with the `f
 
 ## SIMD optimization for the Faiss engine
 
-Starting with version 2.13, the k-NN plugin supports [Single Instruction Multiple Data (SIMD)](https://en.wikipedia.org/wiki/Single_instruction,_multiple_data) processing if the underlying hardware supports SIMD instructions (AVX2 on x64 architecture and Neon on ARM64 architecture). SIMD is supported by default on Linux machines only for the Faiss engine. SIMD architecture helps boost overall performance by improving indexing throughput and reducing search latency.
+Starting with version 2.13, the k-NN plugin supports [Single Instruction Multiple Data (SIMD)](https://en.wikipedia.org/wiki/Single_instruction,_multiple_data) processing if the underlying hardware supports SIMD instructions (AVX2 on x64 architecture and Neon on ARM64 architecture). SIMD is supported by default on Linux machines only for the Faiss engine. SIMD architecture helps boost overall performance by improving indexing throughput and reducing search latency. Starting with version 2.18, the k-NN plugin supports AVX512 on x64 architecture. 
 
 SIMD optimization is applicable only if the vector dimension is a multiple of 8.
 {: .note}
@@ -60,14 +60,19 @@ SIMD optimization is applicable only if the vector dimension is a multiple of 8.
 ### x64 architecture
 <!-- vale on -->
 
-For the x64 architecture, two different versions of the Faiss library are built and shipped with the artifact:
+For the x64 architecture, three different versions of the Faiss library are built and shipped with the artifact:
 
 - `libopensearchknn_faiss.so`: The non-optimized Faiss library without SIMD instructions. 
-- `libopensearchknn_faiss_avx2.so`: The Faiss library that contains AVX2 SIMD instructions. 
+- `libopensearchknn_faiss_avx512.so`: The Faiss library that contains AVX512 SIMD instructions. 
+- `libopensearchknn_faiss_avx2.so`: The Faiss library that contains AVX2 SIMD instructions.
 
-If your hardware supports AVX2, the k-NN plugin loads the `libopensearchknn_faiss_avx2.so` library at runtime.
+The Faiss library order of performance is AVX512, AVX2, generic.
+If your hardware supports AVX512, the k-NN plugin loads the `libopensearchknn_faiss_avx512.so` library at runtime.
+If your hardware supports AVX2 but doesn't support AVX512, the k-NN plugin loads the `libopensearchknn_faiss_avx2.so` library at runtime.
 
-To disable AVX2 and load the non-optimized Faiss library (`libopensearchknn_faiss.so`), specify the `knn.faiss.avx2.disabled` static setting as `true` in `opensearch.yml` (default is `false`). Note that to update a static setting, you must stop the cluster, change the setting, and restart the cluster. For more information, see [Static settings]({{site.url}}{{site.baseurl}}/install-and-configure/configuring-opensearch/index/#static-settings).
+To disable AVX512 and AVX2 and load the non-optimized Faiss library (`libopensearchknn_faiss.so`), specify the `knn.faiss.avx512.disabled` and `knn.faiss.avx2.disabled` static settings as `true` in `opensearch.yml` (defaults are `false`).
+
+Note that to update a static setting, you must stop the cluster, change the setting, and restart the cluster. For more information, see [Static settings]({{site.url}}{{site.baseurl}}/install-and-configure/configuring-opensearch/index/#static-settings).
 
 ### ARM64 architecture
 

_search-plugins/knn/settings.md

@@ -27,6 +27,7 @@ Setting | Static/Dynamic | Default | Description
 `knn.model.index.number_of_replicas`| Dynamic | `1` | The number of replica shards to use for the model system index. Generally, in a multi-node cluster, this value should be at least 1 in order to increase stability.
 `knn.model.cache.size.limit` | Dynamic | `10%` |  The model cache limit cannot exceed 25% of the JVM heap.
 `knn.faiss.avx2.disabled` | Static | `false` | A static setting that specifies whether to disable the SIMD-based `libopensearchknn_faiss_avx2.so` library and load the non-optimized `libopensearchknn_faiss.so` library for the Faiss engine on machines with x64 architecture. For more information, see [SIMD optimization for the Faiss engine]({{site.url}}{{site.baseurl}}/search-plugins/knn/knn-index/#simd-optimization-for-the-faiss-engine).
+`knn.faiss.avx512.disabled` | Static | `false` | A static setting that specifies whether to disable the SIMD-based `libopensearchknn_faiss_avx512.so` library and load the `libopensearchknn_faiss_avx2.so` or the non-optimized `libopensearchknn_faiss.so` library for the Faiss engine on machines with x64 architecture. For more information, see [SIMD optimization for the Faiss engine]({{site.url}}{{site.baseurl}}/search-plugins/knn/knn-index/#simd-optimization-for-the-faiss-engine).
 
 ## Index settings