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Tag: time

How to format unix time (sec+usec+nsec) string?

I have this function which works just fine. It gives me current system time the way I need: Now I need to also be able to print timestamps I receive from 3rd party lib in 2-3 variables – sec, usec, nsec (optional). Can I somehow construct timespec from these values and reuse the code I already have? Answer You don’t

How to correctly time speed of writing to a disk (i.e. file) in C

I have a Zynq SoC which runs a Linux system and would like to time the speed at which I can write to its SD card in C. I have tried out clock() and clock_gettime() where for the latter, I have done the following: The times that I’m getting are around 0.019 seconds for 2097152 bytes which I believe is

Adding data based on date from another dataframe

I have two datasets. One with multiple dates: and one with sunrise and sunsets data: I want to add a column to the first dataframe with either “Day” or “night”, based on whether the date and time from the first dataframe is between the sunrise and sunset time and dates. I tried copying and if_else functions, but the length of

Wall time and cpu time in Linux command time

When I use Linux time command to measure time spent for running a command, which one below corresponds to CPU time and wall time? Answer which one below corresponds to CPU time user is cpu time in user mode, sys is cpu time in kernel mode and wall time? real

Control loop time with usleep

I try to make sure the execution time of each loop to 10ms with usleep , but sometimes it exceeds 10ms. I have no idea how to solve this problem, is it proper to use usleep and gettimeofday in this case? Please help my find out what i missed. Result: 0.0127289 0.0136499 0.0151598 0.0114031 0.014801 Answer To keep the loop

Measuring execution time – in program code or in shell?

I have a program and I want to measure its execution (wallclock) time for different input sizes. In some other similar questions I read that using clock_gettime in the source code wouldn’t be reliable because of the CPUs branch predictor, register renaming, speculative execution, out-of-order execution etc., and sometimes even the optimizer can move the clock_gettime call someplace other than

uninterrupted execution of Cpp Linux code

Hi is there a method on which I can make my code safe from other OS interrupts etc in Linux GNU? For example if I have the code below and I need to find the exact execution time without other things interrupting my code. I have already looked into pthread_mutex_lock(&cs_mutex); but wasn’t able to stop other operations to run. Answer

Memory used by compiling a code

I use time command to measure the time used to execute a file as: My question: are there any command like time can give the memory used by executing an executable file in linux? Answer You can use /usr/bin/time -v ./filename. It will print a lot of information including memory use. Note: Will use the shell built-in time command.