Linux and UNIX Man Pages

Linux & Unix Commands - Search Man Pages

yield(9) [netbsd man page]

PREEMPT(9)						   BSD Kernel Developer's Manual						PREEMPT(9)

NAME
preempt, yield -- general preempt and yield functions SYNOPSIS
#include <sys/sched.h> void preempt(void); #include <sys/proc.h> void yield(void); DESCRIPTION
The preempt() function puts the current LWP back on the system run queue and performs an involuntary context switch. The yield() function is mostly same as preempt(), except that it performs a voluntary context switch. These functions drop the kernel lock before switching and re-acquire it before returning. BSD
July 3, 2007 BSD

Check Out this Related Man Page

CRITICAL_ENTER(9)					   BSD Kernel Developer's Manual					 CRITICAL_ENTER(9)

NAME
critical_enter, critical_exit -- enter and exit a critical region SYNOPSIS
#include <sys/param.h> #include <sys/systm.h> void critical_enter(void); void critical_exit(void); DESCRIPTION
These functions are used to prevent preemption in a critical region of code. All that is guaranteed is that the thread currently executing on a CPU will not be preempted. Specifically, a thread in a critical region will not migrate to another CPU while it is in a critical region. The current CPU may still trigger faults and exceptions during a critical section; however, these faults are usually fatal. The critical_enter() and critical_exit() functions manage a per-thread counter to handle nested critical sections. If a thread is made runnable that would normally preempt the current thread while the current thread is in a critical section, then the preemption will be deferred until the current thread exits the outermost critical section. Note that these functions are not required to provide any inter-CPU synchronization, data protection, or memory ordering guarantees and thus should not be used to protect shared data structures. These functions should be used with care as an infinite loop within a critical region will deadlock the CPU. Also, they should not be inter- locked with operations on mutexes, sx locks, semaphores, or other synchronization primitives. One exception to this is that spin mutexes include a critical section, so in certain cases critical sections may be interlocked with spin mutexes. HISTORY
These functions were introduced in FreeBSD 5.0. BSD
October 5, 2005 BSD
Man Page

6 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Puzzle: file name grepped from text file yields "no such file"

Dear all, In a bash script, I grep a filename from an UTF8 encoded file: LIST=`grep ^source $FILE | tr "\t" " " | cut -d " " -f 2 | sed -e 's,~,\$HOME,g'` The result is # echo $LIST $HOME/.mail_aliases_seminaire_MMMG Then I try to access it: #ls $LIST ls: cannot access... (3 Replies)
Discussion started by: josce
3 Replies

2. Shell Programming and Scripting

exec perl in expect script yields "invalid command"

I'm trying to execute something like this: exec perl -i -pe 's/\015/\012/g' '${file}' in my expect script and I get: error "invalid command name \"perl\". however, if I run perl -i -pe 's/\015/\012/g' "/Users/Shared/menu-items.txt" directly in my terminal, it runs fine. I'm an... (4 Replies)
Discussion started by: dpouliot
4 Replies

3. Forum Support Area for Unregistered Users & Account Problems

UNIX.com links from Google yield invalid thread error

If one enters a Google search query like site:unix.com mysql php and clicks on the resulting link, one gets the message below: vBulletin Message No Thread specified. If you followed a valid link, please notify the administrator (2 Replies)
Discussion started by: Unregistered
2 Replies

4. UNIX for Dummies Questions & Answers

Cp via NFS vs. scp yields unexpected difference

I have two Linux machines, Linux1 and Linux2. They both have two NFS mounts. We'll call them /scratch1 and /scratch2. And they both reside on the same NetApp filer. If I copy a 512Mb file from /scratch1 to /scratch2 while logged on Linux1 it takes 40s. However if I scp this file from... (1 Reply)
Discussion started by: crimso
1 Replies

5. Shell Programming and Scripting

awk output yields error: awk:can't open job_name (Autosys)

Good evening, Im newbie at unix specially with awk From an scheduler program called Autosys i want to extract some data reading an inputfile that comprises jobs names, then formating the output to columns for example 1. This is the inputfile: $ more MapaRep.txt ds_extra_nikira_usuarios... (18 Replies)
Discussion started by: alexcol
18 Replies

6. UNIX for Beginners Questions & Answers

Simple conditional yields too many responses

In this script: #!/bin/bash # bird read -p "Enter name of a bird " REPLY=$REPLY birdname="duck sparrow hawk" for i in $birdname do if ] then echo "Yes, that is a bird." else echo "That is not a bird." fi done I get... (9 Replies)
Discussion started by: Xubuntu56
9 Replies