How to track memory consumption of a application

[suab321321]

Hello, I want to monitor real time memory consumption of a running c++ application (in linux).
I want to know if I can do that using command line utility pcm-memory.x?

I am able to do it using c++ api provided, but I want to know if I can monitor using command line utility?

Thanks

[suab321321]

@opcm

[opcm]

do you want to monitor memory consumption or memory bandwidth consumption? PCM can only monitor memory bandwidth. Please also Q7: https://github.com/opcm/pcm/blob/master/FAQ.md

[suab321321]

hey @opcm I want to monitor memory bandwidth consumption.

[suab321321]

@opcm what I have tried,

1. in one terminal I am running ./pcm-memory.x
2. in another termminal running a very simple my c++ application, this application allocates memory via malloc in the interval of 5 seconds.
   I should see some diff output in the output of pcm-memory.x right when my c++ application code is running? But I m not seeing any of diff output, this is what I see

my sample c++ code

#include <unistd.h>
#include <iostream>

using namespace std;

int main(){
for(int i=0;i<1000;i++){
long* c = (long*)malloc(sizeof(long)*10);
cout<<"allocated"<<endl;
sleep(2);
}
}

[opcm]

the memory allocation alone does not generate memory bandwidth. You need to read/write the memory. Also the array/accessed data needs to be larger than the CPU cache size to trigger memory bandwidth. Try 200 MB or larger arrays.

[suab321321]

@opcm I tried to allocate 200 MB data (1024*1024*200) after this I tried to do memset and then free, even after doing I m not able to see any changes in ./pcm-memory.x.

I would like to point out some more info, this is what my internal of pcm-memory.cpp looks

int memfrq=0, memch=0, memcap=0,maxf=0,numcore=0,insize=0;
   memcap = atoi(argv[1]);
   memfrq = atoi(argv[2]);
   memch = atoi(argv[3]);
   maxf = atoi(argv[4]);
   numcore = atoi(argv[5]);
   insize = atoi(argv[6]);

I am running the exec pcm-memory with parameters like this ./pcm-memory.x 1 2 3 4 5 6 because I dont understand the variables memcap,memfreq means so I just put random values

[ogbrugge]

Your compiler might optimize it away, and just one time may not be enough to see a change. Von meinem iPad gesendet

…

Am 22.11.2020 um 20:10 schrieb suab321321 ***@***.***>:  @opcm I tried to allocate 200 MB data (10241024200) after this I tried to do memset and then free, even after doing I m not able to see any changes in ./pcm-memory.x. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or unsubscribe.

[opcm]

okay. Your CPU (Kabylake in the screenshot) is not supported by pcm-memory. Please see https://github.com/opcm/pcm/blob/master/FAQ.md#q6

How did you enforce pcm-memory to run? Did you modify pcm source code!?

On your CPU you can monitor the read and write memory bandwidth in pcm.x (READ and WRITE metrics)

[suab321321]

@opcm I did not modify anything it just ran on my system though I need to turn off nmi_watchdog and load the msr module, but I think these are to be done in supported cpu model too. I will try to run the test of intel xeon and see if it works there. Anyways thanks for clearing my doubt

[opcm]

@opcm I tried to allocate 200 MB data (1024*1024*200) after this I tried to do memset and then free, even after doing I m not able to see any changes in ./pcm-memory.x.

I would like to point out some more info, this is what my internal of pcm-memory.cpp looks

int memfrq=0, memch=0, memcap=0,maxf=0,numcore=0,insize=0;

   memcap = atoi(argv[1]);

   memfrq = atoi(argv[2]);

   memch = atoi(argv[3]);

   maxf = atoi(argv[4]);

   numcore = atoi(argv[5]);

   insize = atoi(argv[6]);

I am running the exec pcm-memory with parameters like this ./pcm-memory.x 1 2 3 4 5 6 because I dont understand the variables memcap,memfreq means so I just put random values

this is definitely not pcm-memory code above. I am not sure where did you get it from...

BTW: I have a Kabylake CPU too. pcm-memory.x does not work on it (as expected).

[suab321321]

@opcm But this is what I have in my source code of pcm-memory.cpp
Can you give me the link of correct pcm-memory.cpp

[suab321321]

@opcm can we monitor a simple program using pcm.x or pcm-memory.x, as of now I think I m getting info about the whole system with pcm-memory.x, but what if I want to monitor a particular c++ application, it is possible to do it (without using apis, but via command line utility)

[opcm]

the answers are in the FAQ recommended above..