Numba and Dask at the PyData Foundations Workshop

An overview of the PyData workshop held at IBM's INDEX conference plus information about Conda, Numba, Dask

Transcript

1. Scaling PyData PyData Workshop at IBM Index Conference Travis E. Oliphant Founder, Quansight 1 Credit to Anaconda, Inc. for some of these slides
2. PyData Foundations Workshop Jake VanderPlas Jim Bednar Phillip Cloud Steven Silvester Jason Grout Travis Oliphant
3. 3 • MS/BS degrees in Elec. Comp. Engineering • PhD from Mayo Clinic in Biomedical Engineering (Ultrasound and MRI) • Creator and Developer of SciPy (1998-2009) • Professor at BYU (2001-2007) Inverse Problems • Creator and Developer of NumPy (2005-2012) • Started Numba (2012) • Founder of NumFOCUS / PyData • Python Software Foundation Director (2012) • Co-founder of Continuum Analytics => Anaconda, Inc. • CEO (2012) => Chief Data Scientist (2017) • Founder (2018) of Quansight SciPy
4. 4 Empower domain experts with high-level tools that exploit modern hard-ware Array Oriented Computing expertise
5. • Express domain knowledge directly in arrays (tensors, matrices, vectors) --- easier to teach programming in the specific domain • Can take advantage of parallelism and accelerators • Array expressions Why Array-oriented computing 5 Object Attr1 Attr2 Attr3 Object Attr1 Attr2 Attr3 Object Attr1 Attr2 Attr3 Object Attr1 Attr2 Attr3 Object Attr1 Attr2 Attr3 Object Attr1 Attr2 Attr3 Attr1 Attr2 Attr3 Object1 Object2 Object3 Object4 Object5 Object6
6. • Today’s vector machines (and vector co-processors, or GPUS) were made for array-oriented computing. • The software stack has just not caught up --- unfortunate because APL came out in 1963. • There is a reason Fortran remains popular. More reasons for array-oriented 6
7. 7 Python and in particular PyData is Growing
8. Data Science Workflow 8 New Data Notebooks Understand Data Getting Data Understand World Reports Microservices Dashboards Applications Decisions and Actions Models Exploratory Data Analysis and Viz Data Products
9. Machine Learning Explosion 9 Scikit-Learn Tensorflow Keras XGBoost Torch MxNet theano lasagne caffe/caffe2 minpy neon CNTK DAAL Chainer Dynet Apache Singa Shogun CuPy https://github.com/josephmisiti/awesome-machine-learning#python-general-purpose http://deeplearning.net/software_links/ http://scikit-learn.org/stable/related_projects.html
10. 10 A Representation of Packages for ML © 2017 Anaconda, Inc. - Confidential & Proprietary
11. 11 NumPy and Packages that Depend on It © 2017 Anaconda, Inc. - Confidential & Proprietary
12. 12 pandas Depends on NumPy
 (and other packages depend on pandas) © 2017 Anaconda, Inc. - Confidential & Proprietary
13. 13 Caffe Depends on pandas and NumPy © 2017 Anaconda, Inc. - Confidential & Proprietary
14. Embrace Innovation Without Anarchy 14 From http://www.slideshare.net/RevolutionAnalytics/r-at-microsoft Reproducibility
15. 15 Conda Conda Forge Conda Environments Anaconda Project A cross-platform and language agnostic package and environment manager A community-led collection of recipes, build infrastructure, and packages for conda. Custom isolated software sandboxes to allow easy reproducibility and sharing of data-science work. Reproducible, executable project directories
16. • Language independent • Platform independent • No special privileges required • No VMs or containers • Enables: - Reproducibility - Collaboration - Scaling “conda – package everything” 16 A Python v2.7 Conda Sandboxing Technology B Python v3.4 Pandas v0.18 Jupyter C R R Essentials conda NumPy v1.11 NumPy v1.10 Pandas v0.16
17. Basic Conda Usage 17 Install a package conda install sympy List all installed packages conda list Search for packages conda search llvm Create a new environment conda create -n py3k python=3 Remove a package conda remove nose Get help conda install --help
18. Advanced Conda Usage 18 Install a package in an environment conda install -n py3k sympy Update all packages conda update --all Export list of packages conda list --export packages.txt Install packages from an export conda install --file packages.txt See package history conda list --revisions Revert to a revision conda install --revision 23 Remove unused packages and cached tarballs conda clean -pt
19. 19 Development Deployment Conda eases rapid deployment of ML
20. Scaling Up and Out with Numba and Dask 20
21. Scale Up vs Scale Out 21 Big Memory & Many Cores / GPU Box Best of Both (e.g. GPU Cluster) Many commodity nodes in a cluster Scale Up (Bigger Nodes) Scale Out (More Nodes) Numba Dask Dask with Numba
22. © 2017 Anaconda, Inc. - Confidential & Proprietary Development Name Latest Release Number of Releases GitHub Stars Contributors Downloads in 2017 numba 0.37 101 2907 77 ~2m dask 0.17.0 41 2444 136 ~1.5m dask-ml 0.4.1 9 188 8 New Numba Dask Dask-ml http://numba.pydata.org http://github.com/numba http://dask.pydata.org http://github.com/dask http://dask-ml.readthedocs.io/en/latest/index.html http://github.com/dask/dask-ml
23. Numba 23 Credit: Stan Seibert for many of these slides
24. Numba (compile Python to CPUs and GPUs) 24 conda install numba Intermediate Representation (IR) x86 ARM PTX Python LLVM Numba Code Generation Backend Parsing Frontend
25. 25 @jit('void(f8[:,:],f8[:,:],f8[:,:])') def filter(image, filt, output): M, N = image.shape m, n = filt.shape for i in range(m//2, M-m//2): for j in range(n//2, N-n//2): result = 0.0 for k in range(m): for l in range(n): result += image[i+k-m//2,j+l-n//2]*filt[k, l] output[i,j] = result ~1500x speed-up Image Processing
26. Works with and does not replace the standard Python interpreter
 (all of your existing Python libraries are still available) Numba Features 26
27. 7 things about Numba you may not know 27 1 2 3 4 5 6 7 Numba is 100% Open Source Numba + Jupyter = Rapid CUDA Prototyping Numba can compile for the CPU and the GPU at the same time Numba makes array processing easy with @(gu)vectorize Numba comes with a CUDA Simulator You can send Numba functions over the network Numba developers are working On a GPU DataFrame (pygdf)
28. Other Numba topics 28 CUDA Python — write general GPU kernels with Python Device Arrays — manage memory transfer from host to GPU Streaming — manage asynchronous and parallel GPU compute streams CUDA Simulator in Python — to help debug your kernels HSA Support — early support for HSA-based GPUs and APUs Pyculib — access to cuFFT, cuBLAS, cuSPARSE, cuRAND, CUDA Sorting Parallel Acceleration — prange, parallel functions, and more https://github.com/ContinuumIO/gtc2017-numba
29. © 2017 Anaconda, Inc. - Confidential & Proprietary • Detects CPU model during compilation and optimizes for that target • Automatic type inference: No need to give type signatures for functions • Dispatches to multiple type-specializations for the same function • Call out to C libraries with CFFI and types • Special "callback" mode for creating C callbacks to use with external libraries • Optional caching to disk, and ahead-of-time creation of shared libraries • Compiler is extensible with new data types and functions Numba Features
30. © 2017 Anaconda, Inc. - Confidential & Proprietary • Three main technologies for parallelism: Parallel Computing SIMD Multi-threading Distributed Computing x0 x1 x2 x3 x0 x1 x2 x3 x0 x3 x2 x1
31. © 2017 Anaconda, Inc. - Confidential & Proprietary • Numba's CPU detection will enable LLVM to autovectorize for appropriate SIMD instruction set: • SSE, AVX, AVX2, AVX-512 • Will become even more important as AVX-512 is now available on both Xeon Phi and Skylake Xeon processors SIMD: Single Instruction Multiple Data
32. © 2017 Anaconda, Inc. - Confidential & Proprietary Manual Multithreading: Release the GIL Speedup Ratio 0 0.9 1.8 2.6 3.5 Number of Threads 1 2 4 Option to release the GIL Using Python concurrent.futures
33. © 2017 Anaconda, Inc. - Confidential & Proprietary Universal Functions (Ufuncs) Ufuncs are a core concept in NumPy for array-oriented computing. ◦ A function with scalar inputs is broadcast across the elements of the input arrays: • np.add([1,2,3], 3) == [4, 5, 6] • np.add([1,2,3], [10, 20, 30]) == [11, 22, 33] ◦ Parallelism is present, by construction. Numba will generate loops and can automatically multi-thread if requested. ◦ Before Numba, creating fast ufuncs required writing C. No longer!
34. © 2017 Anaconda, Inc. - Confidential & Proprietary Universal Functions (Ufuncs) Different decorator! 1.8x speedup!
35. © 2017 Anaconda, Inc. - Confidential & Proprietary Multi-threaded Ufuncs Specify type signature Select parallel target Automatically uses all CPU cores!
36. © 2017 Anaconda, Inc. - Confidential & Proprietary ParallelAccelerator • ParallelAccelerator is a special compiler pass contributed by Intel Labs • Todd A. Anderson, Ehsan Totoni, Paul Liu • Based on similar contribution to Julia • Automatically generates mulithreaded code in a Numba compiled-function: • Array expressions and reductions • Random functions • Dot products • Explicit loops indicated with prange() call
37. © 2017 Anaconda, Inc. - Confidential & Proprietary ParallelAccelerator: Example #1 Time (ms) 0 1000 2000 3000 4000 NumPy Numba Numba+PA 1.8x 3.6x 1000000x10 input, Core i7 Quad Core CPU
38. © 2017 Anaconda, Inc. - Confidential & Proprietary ParallelAccelerator: prange() Time (ms) 0 25 50 75 100 NumPy Numba Numba+PA 4.3x 50x 1000000x10 input, Core i7 Quad Core CPU
39. © 2017 Anaconda, Inc. - Confidential & Proprietary ParallelAccelerator: prange() Time (ms) 0 25 50 75 100 NumPy Numba Numba+PA 2x 3.6x 1000000x10 input, Core i7 Quad Core CPU
40. © 2017 Anaconda, Inc. - Confidential & Proprietary ParallelAccelerator: Image Resampling https://github.com/bokeh/ datashader/blob/master/ examples/landsat.ipynb Interactive image resampling with Holoviews + Datashader Datashader resampling implemented with Numba + prange()
41. © 2017 Anaconda, Inc. - Confidential & Proprietary ParallelAccelerator: Stencils 730x547 image w/ 21x21 pixel blur half the lines of code and 4x faster on a quad core CPU than equivalent non-stencil Numba code
42. Dask 42 Credit Matthew Rocklin for many of these slides
43. • Designed to parallelize the Python ecosystem • Handles complex algorithms • Co-developed with Pandas/SKLearn/Jupyter teams • Familiar APIs for Python users • Scales • Scales from multicore to 1000-node clusters • Resilience, responsive, and real-time
44. • Parallelizes NumPy, Pandas, SKLearn • Satisfies subset of these APIs • Uses these libraries internally • Co-developed with these teams • Task scheduler supports custom algorithms • Parallelize existing code • Build novel real-time systems • Arbitrary task graphs 
 with data dependencies • Same scalability
45. Dask: From User Interaction to Execution 45 delayed
46. 46 >>> import pandas as pd >>> df = pd.read_csv('iris.csv') >>> df.head() sepal_length sepal_width petal_length petal_width species 0 5.1 3.5 1.4 0.2 Iris-setosa 1 4.9 3.0 1.4 0.2 Iris-setosa 2 4.7 3.2 1.3 0.2 Iris-setosa 3 4.6 3.1 1.5 0.2 Iris-setosa 4 5.0 3.6 1.4 0.2 Iris-setosa >>> max_sepal_length_setosa = df[df.species == 'setosa'].sepal_length.max() 5.7999999999999998 >>> import dask.dataframe as dd >>> ddf = dd.read_csv('*.csv') >>> ddf.head() sepal_length sepal_width petal_length petal_width species 0 5.1 3.5 1.4 0.2 Iris-setosa 1 4.9 3.0 1.4 0.2 Iris-setosa 2 4.7 3.2 1.3 0.2 Iris-setosa 3 4.6 3.1 1.5 0.2 Iris-setosa 4 5.0 3.6 1.4 0.2 Iris-setosa … >>> d_max_sepal_length_setosa = ddf[ddf.species == 'setosa'].sepal_length.max() >>> d_max_sepal_length_setosa.compute() 5.7999999999999998 Dask DataFrame is like Pandas
47. Example 1: Using Dask DataFrames on a cluster with CSV data 47 • Built from Pandas DataFrames • Match Pandas interface • Access data from HDFS, S3, local, etc. • Fast, low latency • Responsive user interface
48. 48 >>> import numpy as np >>> np_ones = np.ones((5000, 1000)) >>> np_ones array([[ 1., 1., 1., ..., 1., 1., 1.], [ 1., 1., 1., ..., 1., 1., 1.], [ 1., 1., 1., ..., 1., 1., 1.], ..., [ 1., 1., 1., ..., 1., 1., 1.], [ 1., 1., 1., ..., 1., 1., 1.], [ 1., 1., 1., ..., 1., 1., 1.]]) >>> np_y = np.log(np_ones + 1)[:5].sum(axis=1) >>> np_y array([ 693.14718056, 693.14718056, 693.14718056, 693.14718056, 693.14718056]) >>> import dask.array as da >>> da_ones = da.ones((5000000, 1000000), chunks=(1000, 1000)) >>> da_ones.compute() array([[ 1., 1., 1., ..., 1., 1., 1.], [ 1., 1., 1., ..., 1., 1., 1.], [ 1., 1., 1., ..., 1., 1., 1.], ..., [ 1., 1., 1., ..., 1., 1., 1.], [ 1., 1., 1., ..., 1., 1., 1.], [ 1., 1., 1., ..., 1., 1., 1.]]) >>> da_y = da.log(da_ones + 1)[:5].sum(axis=1) >>> np_da_y = np.array(da_y) #fits in memory array([ 693.14718056, 693.14718056, 693.14718056, 693.14718056, …, 693.14718056]) # If result doesn’t fit in memory >>> da_y.to_hdf5('myfile.hdf5', 'result') Dask Array is like NumPy
49. Example 3: Using Dask Arrays with global temperature data 49 • Built from NumPy
 n-dimensional arrays • Matches NumPy interface (subset) • Solve medium-large problems • Complex algorithms
50. Dask Schedulers: Distributed Scheduler 50
51. Scheduler Visualization with Bokeh 51
52. Ten Reasons People Choose Dask
53. Scalable Pandas DataFrames • Same API
 import dask.dataframe as dd
 df = dd.read_parquet(‘s3://bucket/accounts/2017')
 df.groupby(df.name).value.mean().compute() • Efficient Timeseries Operations
 df.loc[‘2017-01-01’] # Uses the Pandas index…
 df.value.rolling(10).std() # for efficient…
 df.value.resample(‘10m’).mean() # operations. • Co-developed with Pandas
 and by the Pandas developer community
54. Scalable NumPy Arrays • Same API
 
 import dask.array as da
 x = da.from_array(my_hdf5_file)
 y = x.dot(x.T) • Applications • Atmospheric science • Satellite imagery • Biomedical imagery • Optimization algorithms
 check out dask-glm
55. Parallelize Scikit-Learn/Joblib • Scikit-Learn parallelizes with Joblib
 
 estimator = RandomForest(…)
 
 estimator.fit(train_data, train_labels, njobs=8) • Joblib can use Dask
 
 from sklearn.externals.joblib import parallel_backend
 with parallel_backend('dask', scheduler=‘…’): estimator.fit(train_data, train_labels) https://pythonhosted.org/joblib/ http://distributed.readthedocs.io/en/latest/joblib.html Joblib Thread pool
56. Parallelize Scikit-Learn/Joblib • Scikit-Learn parallelizes with Joblib
 
 estimator = RandomForest(…)
 
 estimator.fit(train_data, train_labels, njobs=8) • Joblib can use Dask
 
 from sklearn.externals.joblib import parallel_backend
 with parallel_backend('dask', scheduler=‘…’): estimator.fit(train_data, train_labels) https://pythonhosted.org/joblib/ http://distributed.readthedocs.io/en/latest/joblib.html Joblib Dask
57. Many Other Libraries in Anaconda • Scikit-Image uses dask to break down images and speed up algorithms with overlapping regions • Geopandas can use Dask to partition data spatially and accelerate spatial joins
58. Dask Scales Up • Thousand node clusters • Cloud computing • Super computers • Gigabyte/s bandwidth • 200 microsecond task overhead Dask Scales Down (the median cluster size is one) • Can run in a single Python thread pool • Almost no performance penalty (microseconds) • Lightweight • Few dependencies • Easy install
59. Parallelize Web Backends • Web servers process thousands of small computations asynchronously
 for web pages or REST endpoints • Dask provides dynamic, heterogenous computation • Supports small data • 10ms roundtrip times • Dynamic scaling for different loads • Supports asynchronous Python (like GoLang)
 
 async def serve(request):
 future = dask_client.submit(process, request)
 result = await future
 return result
60. Debugging support • Clean Python tracebacks when user code breaks • Connect to remote workers with IPython sessions 
 for advanced debugging
61. Resource constraints • Define limited hardware resources for workers • Specify resource constraints when submitting tasks $ dask-worker … —resources GPU=2 $ dask-worker … —resources GPU=2 $ dask-worker … —resources special-db=1 future = client.submit(my_function, resources={‘GPU’: 1}) • Used for GPUs, big-memory machines, special hardware, database connections, I/O machines, etc..
62. Collaboration • Many users can share the same cluster simultaneously • Define public datasets • Repeated computation and data use is shared among everyone df = dd.read_parquet(…).persist() client.publish_dataset(accounts=df) df = client.get_dataset(‘accounts’)
63. Beautiful Diagnostic Dashboards • Fast responsive dashboards • Provide users performance insight • Powered by Bokeh
64. Some Reasons not to Choose Dask
65. • Dask is not a SQL database. 
 Does Pandas well, but won’t optimize complex queries. • Dask is not MPI
 Very fast, but does leave some performance on the table
 200us task overhead
 a couple copies in the network stack • Dask is not a JVM technology
 It’s a Python library
 (although Julia bindings available) • Dask is not always necessary 
 You may not need parallelism Dask’s limitations
66. dask.pydata.org conda install dask