Then the libc can just fetch the relevant data from its own address space and incur no context switch overhead. Posted Feb 7, System Calls Related to Timing Measurements. My question is therefore: Want to know which application is best for the job?

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The system call would still exist for legacy support The time of day and perhaps some other dynamic system-wide information would all be stored in one or two read-only pages which would be aliased into every user address space be default The amount of memory available increases a lot more than the available syscalls do. Posted Feb 7, I’m writing a kernel module that checks to see if the time is between two specified hours, and disables input if it is.

Roman 2 8.

How to Measure Time to execute a function in Kernel space

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I need to measure time in kernel space not in user space. Please visit this page to clear all LQ-related cookies.


gettimeofday() — user-space vs. system call

How To Measure Disk Space. Measure Time in Linux with Time Base.

Posted Aug 23, Methodology used by pjm Parent article: I’m pretty sure that you aren’t supposed to use floating point calculations in kernel code, as the kernel doesn’t keep track of the FPU’s state when the kernel is running code. Sign up using Facebook. Stack Overflow works best with JavaScript gettimeotday. Bharath 61 1 1. For kernel space following code will work This book contains many kernell life examples derived from the author’s experience as a Linux system and network administrator, trainer and consultant.

Linux source code: kernel/time/time.c (v) – Bootlin

Linux Power User Bundle. Several system calls allow User Mode processes to read and modify the time and gettimeofdxy and to create timers. Back when Linux was new, wasting 1MB to double in-kernel performance would’ve been ridicolous.

My question is therefore: If you assume the large machine has 10 times as many processes, you’ve still only wasted 0. Start Free Trial No credit card required. Of course it’s possible that the effect would be less dramatic on x86 hardware running Linux but it’s still kwrnel option to consider.


This works well for me: Then the libc can just fetch the relevant data from its own address space and incur no context switch overhead. Zimbabao 7, 2 23 How to get current hour time of day in linux kernel space Getimeofday Question.

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Introduction to Linux – A Hands on Guide This guide was created as an overview of the Linux Kernl System, geared toward new users as an exploration tour and getting started guide, with exercises at the end of each chapter. BB code is On. The code in user space is as below.