Perf record in MPI application

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Perf record in MPI application

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#1 by (0 votes)

1

I would like to collect statistics from an MPI application

To write the application running on a single machine, I can use the command:

perf record mpirun -np $NUMBER_OF_CORES app_name

However, when executing this command to distribute the task on more than one machine, the logged events are only from the local machine - which I triggered the execution

To register each of the processes, I created a script that calls the perf in each of the subprocesses

#!/bin/bash
app=$1
perf record -m 512G -o "${app}-${RANDOM}.perf.data ${app}

And I execute as follows:

mpirun -np $NUMBER_OF_CORES perf_record.sh app_name

However, the generated files did not record any events

The app_name-123.perf.data file has no samples!

1 - What am I doing wrong?

2 - Is there any other tool that is best suited for use with MPI applications?

Obs, I'm really interested in the time spent on each of the functions of the program and not on the time of communication

linux profiling

asked by anonymous 19.06.2018 / 17:01

1 answer

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score 0 · Answer 1

Actually the problem was in -m 512G , passing a high value thus, no event was recorded, as described here .

This flag was added to work around the problem

Permission error mapping pages.
Consider increasing /proc/sys/kernel/perf_event_mlock_kb,
or try again with a smaller value of mmap_pages.

But in fact the correct solution would be to add write permissions to the user, as described here . This could be done through the commands:

Temporary:

sudo sh -c 'echo -1 >/proc/sys/kernel/perf_event_paranoid'
sudo sh -c 'echo 0 > /proc/sys/kernel/kptr_restrict'

Persistently:

sudo sh -c 'echo kernel.perf_event_paranoid=-1 >> /etc/sysctl.d/local.conf'
sudo sh -c 'echo kernel.kptr_restrict=0 >> /etc/sysctl.d/local.conf'