Xtykutl

I am using Anaconda environment on macOS High Sierra and could not run XGBoost with 8 thread even though I set the nthread parameter to 8.

The python code is like this. When I run it, I monitor the execution by looking at htop. There is only one process which is 100%.

clf = xgb.XGBClassifier(

     **xgb_params,

     n_estimators=1000,

     nthread=8

)

Then I searched on the internet and found this link. Some people refer this one and I followed it.

https://www.ibm.com/developerworks/community/blogs/jfp/entry/Installing_XGBoost_on_Mac_OSX?lang=en

➜  ~ brew install gcc --without-multilib

Warning: gcc 8.2.0 is already installed and up-to-date

To reinstall 8.2.0, run `brew reinstall gcc`

After seeing this info, I added the following lines to my xgboost config

export CC = gcc-8

export CXX = g++-8

When the build is done. I tried it again and nothing changed.

So, I kept searching the solution. I found this page.

https://clang-omp.github.io/

Then I ran the following line.

brew install llvm

And I tried to do the example in that site. I created a file, which is called hello.c, and put the following code inside.

#include <omp.h>

#include <stdio.h>

int main() {

#pragma omp parallel

  printf("Hello from thread %d, nthreads %dn", omp_get_thread_num(), 

  omp_get_num_threads());

}

Then I tried to compile it as mentioned.

clang -fopenmp hello.c -o hello

It worked! I also tried gcc-8 as follows.

gcc-8 -fopenmp hello.c -o hello

It also worked. So, this is the output when I run ./hello

➜  ~ ./hello 

Hello from thread 4, nthreads 8

Hello from thread 7, nthreads 8

Hello from thread 2, nthreads 8

Hello from thread 1, nthreads 8

Hello from thread 6, nthreads 8

Hello from thread 3, nthreads 8

Hello from thread 0, nthreads 8

Hello from thread 5, nthreads 8

So, I added gcc-8 in xgboost config file and gcc-8 is able to run in parallel with -fopenmp option as you can see. However, XGBoost does not run in parallel even though I compile it with this setting and set the nthread parameter to 8.

Is there any idea that I can try more?

Edit 1: I tried more complex code to ensure parellalization works. I tried this code. The output shows 8 thread work. I also see it by typing htop.

➜  ~ clang -fopenmp OpenMP.c -o OpenMP

➜  ~ ./OpenMP 

---- Serial

---- Serial done in 37.058571 seconds.

---- Parallel

---- Parallel done in 9.674641 seconds.

---- Check

Passed

Edit 2: I installed gcc-7 and did same process. It did not work either.