Single precision histograms on GPU (#3965)

* Allow single precision histogram summation in gpu_hist

* Add python test, reduce run-time of gpu_hist tests

* Update documentation
This commit is contained in:
Rory Mitchell
2018-12-10 10:55:30 +13:00
committed by GitHub
parent 9af6b689d6
commit 93f9ce9ef9
10 changed files with 351 additions and 212 deletions

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@@ -37,30 +37,34 @@ Supported parameters
.. |tick| unicode:: U+2714
.. |cross| unicode:: U+2718
+--------------------------+---------------+--------------+
| parameter | ``gpu_exact`` | ``gpu_hist`` |
+==========================+===============+==============+
| ``subsample`` | |cross| | |tick| |
+--------------------------+---------------+--------------+
| ``colsample_bytree`` | |cross| | |tick| |
+--------------------------+---------------+--------------+
| ``colsample_bylevel`` | |cross| | |tick| |
+--------------------------+---------------+--------------+
| ``max_bin`` | |cross| | |tick| |
+--------------------------+---------------+--------------+
| ``gpu_id`` | |tick| | |tick| |
+--------------------------+---------------+--------------+
| ``n_gpus`` | |cross| | |tick| |
+--------------------------+---------------+--------------+
| ``predictor`` | |tick| | |tick| |
+--------------------------+---------------+--------------+
| ``grow_policy`` | |cross| | |tick| |
+--------------------------+---------------+--------------+
| ``monotone_constraints`` | |cross| | |tick| |
+--------------------------+---------------+--------------+
+--------------------------------+---------------+--------------+
| parameter | ``gpu_exact`` | ``gpu_hist`` |
+================================+===============+==============+
| ``subsample`` | |cross| | |tick| |
+--------------------------------+---------------+--------------+
| ``colsample_bytree`` | |cross| | |tick| |
+--------------------------------+---------------+--------------+
| ``colsample_bylevel`` | |cross| | |tick| |
+--------------------------------+---------------+--------------+
| ``max_bin`` | |cross| | |tick| |
+--------------------------------+---------------+--------------+
| ``gpu_id`` | |tick| | |tick| |
+--------------------------------+---------------+--------------+
| ``n_gpus`` | |cross| | |tick| |
+--------------------------------+---------------+--------------+
| ``predictor`` | |tick| | |tick| |
+--------------------------------+---------------+--------------+
| ``grow_policy`` | |cross| | |tick| |
+--------------------------------+---------------+--------------+
| ``monotone_constraints`` | |cross| | |tick| |
+--------------------------------+---------------+--------------+
| ``single_precision_histogram`` | |cross| | |tick| |
+--------------------------------+---------------+--------------+
GPU accelerated prediction is enabled by default for the above mentioned ``tree_method`` parameters but can be switched to CPU prediction by setting ``predictor`` to ``cpu_predictor``. This could be useful if you want to conserve GPU memory. Likewise when using CPU algorithms, GPU accelerated prediction can be enabled by setting ``predictor`` to ``gpu_predictor``.
The experimental parameter ``single_precision_histogram`` can be set to True to enable building histograms using single precision. This may improve speed, in particular on older architectures.
The device ordinal can be selected using the ``gpu_id`` parameter, which defaults to 0.
Multiple GPUs can be used with the ``gpu_hist`` tree method using the ``n_gpus`` parameter. which defaults to 1. If this is set to -1 all available GPUs will be used. If ``gpu_id`` is specified as non-zero, the selected gpu devices will be from ``gpu_id`` to ``gpu_id+n_gpus``, please note that ``gpu_id+n_gpus`` must be less than or equal to the number of available GPUs on your system. As with GPU vs. CPU, multi-GPU will not always be faster than a single GPU due to PCI bus bandwidth that can limit performance.
@@ -121,6 +125,52 @@ For multi-gpu support, objective functions also honor the ``n_gpus`` parameter,
which, by default is set to 1. To disable running objectives on GPU, just set
``n_gpus`` to 0.
Metric functions
===================
Following table shows current support status for evaluation metrics on the GPU.
.. |tick| unicode:: U+2714
.. |cross| unicode:: U+2718
+-----------------+-------------+
| Metric | GPU Support |
+=================+=============+
| rmse | |tick| |
+-----------------+-------------+
| mae | |tick| |
+-----------------+-------------+
| logloss | |tick| |
+-----------------+-------------+
| error | |tick| |
+-----------------+-------------+
| merror | |cross| |
+-----------------+-------------+
| mlogloss | |cross| |
+-----------------+-------------+
| auc | |cross| |
+-----------------+-------------+
| aucpr | |cross| |
+-----------------+-------------+
| ndcg | |cross| |
+-----------------+-------------+
| map | |cross| |
+-----------------+-------------+
| poisson-nloglik | |tick| |
+-----------------+-------------+
| gamma-nloglik | |tick| |
+-----------------+-------------+
| cox-nloglik | |cross| |
+-----------------+-------------+
| gamma-deviance | |tick| |
+-----------------+-------------+
| tweedie-nloglik | |tick| |
+-----------------+-------------+
As for objective functions, metrics honor the ``n_gpus`` parameter,
which, by default is set to 1. To disable running metrics on GPU, just set
``n_gpus`` to 0.
Benchmarks
==========
You can run benchmarks on synthetic data for binary classification:
@@ -152,12 +202,15 @@ References
`Nvidia Parallel Forall: Gradient Boosting, Decision Trees and XGBoost with CUDA <https://devblogs.nvidia.com/parallelforall/gradient-boosting-decision-trees-xgboost-cuda/>`_
Authors
Contributors
=======
* Rory Mitchell
Many thanks to the following contributors (alphabetical order):
* Andrey Adinets
* Jiaming Yuan
* Jonathan C. McKinney
* Philip Cho
* Rory Mitchell
* Shankara Rao Thejaswi Nanditale
* Vinay Deshpande
* ... and the rest of the H2O.ai and NVIDIA team.
Please report bugs to the user forum https://discuss.xgboost.ai/.