This is my bpf program to profile a kernel function pick_next_task_fiar. It reports error as follow: My question why the bpf can not recognise the struct rq since I have already included the # include <linux/sched.h>. However, it does recognise the struct task_struct. These two structs are in the same h…
Tag: linux
Package fracdiff of R fails to install in Linux Mint
I am installing the package forecast. However, I get a persistent error because the package fracdiff fails with this error: Normally, when I see had non-zero exit status, it is for me a clue telling me that I should go to Synaptic and search for the library r-cran-fracdiff. However, this library is not presen…
bash script unable to ask confirmation
I am initiating myself to shell scripting and I need to ask the user about confirmation. I have this script, which I don’t know why the following command is not working: read -p “Are you sure about this action?” yn I use it twice, at the beggining of the script and in the middle. The first r…
Export Curl information to file using sed
I am trying to get a dns address using curl and I would like to use that dsn address to replace a word in a .js file. So the .js file contains a word “hostname” and I would like to replace that with the dns address fetched from curl so what I am trying to do is this. sed ‘s/hostname/curl
How does pthread_cond_wait (conditon variable) unblock all threads only once, not multiple times?
I have successfully implemented a producer thread and 2 worker threads or consumer threads. The producer thread broadcasts condition using pthread_cond_broadcast. And the worker threads are blocked by pthread_cond_wait. The code looks something likes this: Thread 1 (Producer Thread): Thread 2 (Worker/Consumer…
Is there a way to read the memory counter used by cgroups to kill processes?
I am running a process under a cgroup with an OOM Killer. When it performs a kill, dmesg outputs messages such as the following. I would like to be able to tell how much memory the cgroups OOM Killer believes the process is using at any given time. Is there a way to query for this quantity? Answer I found
Dynamic expansion of the Linux stack
I’ve noticed the Linux stack starts small and expands with page faults caused by recursion/pushes/vlas up to size getrlimit(RLIMIT_STACK,…), give or take (defaults to 8MiB on my system). Curiously though, if I cause page faults by addressing bytes directly, within the limit, Linux will just regula…
Bash get docker image ID automatically
I’m trying to run a few docker commands in my linux machine: But I would like to make a runme.sh and execute all in one run. The problem is that ImageID bf46cff9b182 is dynamiccally changing everytime. So I need to somehow pipe it from the output of the load command, which is in fact possible. The outpu…
Continuous Audio Playback with Sounddevice
I am writing a program to stream audio over a network, so I have a thread to record data and one to send it. When testing the audio has noticeable gaps. I beleive this is due to the sounddevice.play() function, the example below has the same problem. The gaps coincide with the play length, so it appears to be…
How to redirect port for React production
I am trying to setup both Express.js and React.js apps on the same Ubuntu server. This is a VPS which runs Plesk Onyx where we have a lot of virtual hosts that run over port 80. To run them continuosly I have installed and ran forever, then these apps starts on ports 3000and 5000 (for instance). I executed co…