如何在MPI程序中使用ltrace? [英] How to use ltrace for mpi programs?

问题描述

我想知道如何使用ltrace来获取mpi应用程序的库函数调用，但是ltrace无法正常工作，并且我的mpirun无法成功. 有什么主意吗?

I want to know how to use ltrace to get library function calls of mpi application but simply ltrace doesn't work and my mpirun cannot succeed. Any idea?

推荐答案

您应该能够简单地使用:

You should be able to simply use:

$ mpiexec -n 4 -other_mpiexec_options ltrace ./executable

但是这将造成巨大的混乱，因为来自不同等级的输出将合并.更好的选择是将ltrace的输出重定向到每个等级的单独文件.通过一些MPI实现，获得排名很容易.例如，Open MPI导出环境变量OMPI_COMM_WORLD_RANK中的世界排名.以下包装器脚本将有所帮助:

But that will create a huge mess since the outputs from the different ranks will merge. A much better option is to redirect the output of ltrace to a separate file for each rank. Getting the rank is easy with some MPI implementations. For example, Open MPI exports the world rank in the environment variable OMPI_COMM_WORLD_RANK. The following wrapper script would help:

#!/bin/sh

ltrace --output trace.$OMPI_COMM_WORLD_RANK $*

用法:

$ mpiexec -n 4 ... ltrace_wrapper ./executable

这将产生4个跟踪文件，每个级别对应一个文件:trace.0，trace.1，trace.2和trace.3.

This will produce 4 trace files, one for each rank: trace.0, trace.1, trace.2, and trace.3.

对于基于MPICH和基于它的Hydra PM导出PMI_RANK的其他MPI实现，必须修改上述给定脚本，并用PMI_RANK替换OMPI_COMM_WORLD_RANK.也可以编写一个通用包装器，用于两个MPI实现系列.

For MPICH and other MPI implementations based on it and using the Hydra PM exports PMI_RANK and the above given script has to be modified and OMPI_COMM_WORLD_RANK replaced with PMI_RANK. One could also write an universal wrapper that works with both families of MPI implementations.

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