huaxingao commented on a change in pull request #29139: URL: https://github.com/apache/spark/pull/29139#discussion_r457076755
########## File path: docs/ml-guide.md ########## @@ -62,23 +62,13 @@ The primary Machine Learning API for Spark is now the [DataFrame](sql-programmin # Dependencies -MLlib uses the linear algebra package [Breeze](http://www.scalanlp.org/), which depends on -[netlib-java](https://github.com/fommil/netlib-java) for optimised numerical processing. -If native libraries[^1] are not available at runtime, you will see a warning message and a pure JVM -implementation will be used instead. +MLlib uses linear algebra packages [Breeze](http://www.scalanlp.org/) and [netlib-java](https://github.com/fommil/netlib-java) for optimised numerical processing[^1]. Those packages may call native acceleration libraries such as [Intel MKL](https://software.intel.com/content/www/us/en/develop/tools/math-kernel-library.html) or [OpenBLAS](http://www.openblas.net) if they are available as system libraries or in runtime library paths. -Due to licensing issues with runtime proprietary binaries, we do not include `netlib-java`'s native -proxies by default. -To configure `netlib-java` / Breeze to use system optimised binaries, include -`com.github.fommil.netlib:all:1.1.2` (or build Spark with `-Pnetlib-lgpl`) as a dependency of your -project and read the [netlib-java](https://github.com/fommil/netlib-java) documentation for your -platform's additional installation instructions. - -The most popular native BLAS such as [Intel MKL](https://software.intel.com/en-us/mkl), [OpenBLAS](http://www.openblas.net), can use multiple threads in a single operation, which can conflict with Spark's execution model. - -Configuring these BLAS implementations to use a single thread for operations may actually improve performance (see [SPARK-21305](https://issues.apache.org/jira/browse/SPARK-21305)). It is usually optimal to match this to the number of cores each Spark task is configured to use, which is 1 by default and typically left at 1. - -Please refer to resources like the following to understand how to configure the number of threads these BLAS implementations use: [Intel MKL](https://software.intel.com/en-us/articles/recommended-settings-for-calling-intel-mkl-routines-from-multi-threaded-applications) or [Intel oneMKL](https://software.intel.com/en-us/onemkl-linux-developer-guide-improving-performance-with-threading) and [OpenBLAS](https://github.com/xianyi/OpenBLAS/wiki/faq#multi-threaded). Note that if nativeBLAS is not properly configured in system, java implementation(f2jBLAS) will be used as fallback option. +Due to differing OSS licenses, `netlib-java`'s native proxies can't be distributed with Spark. See [MLlib Linear Algebra Acceleration Guide](ml-linalg-guide.md) for how to enable accelerated linear algebra processing. If accelerated native libraries are not enabled, you will see a warning message below and a pure JVM implementation will be used instead: Review comment: `ml-linalg-guide.html` instead of `ml-linalg-guide.md`? ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
