Could you kindly elaborate? I understand that we are searching for httpd. Then you are assigning n to some less than 3. However I may be completely wrong. Your assistance is a greatly appreciated.
Hello all,
How do I start a background process and save the process id to a file on my system. For example %wait 5 & will execute and print the process id. I can't figure out how to get it to a file. I've tried: > filename 0>filename 1>filename.
Any assistance is most appreciated.
Thanks,
Jim... (10 Replies)
Hi,
new to nawk so not sure how this works,
I have a file with three values 23:36:18 - i need to set a variable called SCORE with the highest value from the file (i.e. 36) using nawk
can anyone help?
thanks (1 Reply)
hello,
I have a process lauched by non-root user.
how to lauch this process with a very high priority?
I know this has to do with nice command but how to allow a user to lauch his process with a very high priority and without ROOT intervention?
PS: this process is always lauched from a... (2 Replies)
hi,
i want to know cpu utilizatiion per process per cpu..for single processor also if multicore in linux ..to use these values in shell script to kill processes exceeding cpu utilization.ps (pcpu) command does not give exact values..top does not give persistant values..psstat,vmstat..does njot... (3 Replies)
Hi all,
I'm new in programming, but want to start writing a simple GUI for linux console application,say, wget.(for educational purpose :) ).
The question is:
how to start child process from C++ code and then start capture messages from its stdout?
Thanks in advance. (2 Replies)
Hi ,
I am running a backgorund process called hello.sh
./hello &
Now i need to capture the log file as it produces the output .
i am not able to use " >> " nor " tee " to capture the output file / log file .
Please let me know how can i do it ?
Regards,
Deepak Konnur (3 Replies)
I am sure it has been answered in some form or the other in this forum but trust me I have spent last couple of hours looking for an answer but can't find it.
I want to do a very simple operation within my script.
Let's say I have 4 files with the names file1.log, file2.log, file3.log and... (6 Replies)
Can someone please help me with a script that will help in identifying the CPU & memory usage by a process name, rather than a process id.This is to primarily analyze the consumption of resources, for performance tweaking.
G (4 Replies)
Hi,
Recently i have write a simple script to capture CPU high usage based on prstat but i found out that it did capture correctly. I need to capture the rows that contains CPU usage more than 3%. Below line which i thought will capture CPU usage based CPU column in prstat(9th parameter) which is... (3 Replies)
Discussion started by: tharmendran
3 Replies
LEARN ABOUT POSIX
taskset
TASKSET(1) User Commands TASKSET(1)NAME
taskset - set or retrieve a process's CPU affinity
SYNOPSIS
taskset [options] mask command [argument...]
taskset [options] -p [mask] pid
DESCRIPTION
taskset is used to set or retrieve the CPU affinity of a running process given its pid, or to launch a new command with a given CPU affin-
ity. CPU affinity is a scheduler property that "bonds" a process to a given set of CPUs on the system. The Linux scheduler will honor the
given CPU affinity and the process will not run on any other CPUs. Note that the Linux scheduler also supports natural CPU affinity: the
scheduler attempts to keep processes on the same CPU as long as practical for performance reasons. Therefore, forcing a specific CPU
affinity is useful only in certain applications.
The CPU affinity is represented as a bitmask, with the lowest order bit corresponding to the first logical CPU and the highest order bit
corresponding to the last logical CPU. Not all CPUs may exist on a given system but a mask may specify more CPUs than are present. A
retrieved mask will reflect only the bits that correspond to CPUs physically on the system. If an invalid mask is given (i.e., one that
corresponds to no valid CPUs on the current system) an error is returned. The masks may be specified in hexadecimal (with or without a
leading "0x"), or as a CPU list with the --cpu-list option. For example,
0x00000001 is processor #0,
0x00000003 is processors #0 and #1,
0xFFFFFFFF is processors #0 through #31,
32 is processors #1, #4, and #5,
--cpu-list 0-2,6
is processors #0, #1, #2, and #6.
When taskset returns, it is guaranteed that the given program has been scheduled to a legal CPU.
OPTIONS -a, --all-tasks
Set or retrieve the CPU affinity of all the tasks (threads) for a given PID.
-c, --cpu-list
Interpret mask as numerical list of processors instead of a bitmask. Numbers are separated by commas and may include ranges. For
example: 0,5,8-11.
-p, --pid
Operate on an existing PID and do not launch a new task.
-V, --version
Display version information and exit.
-h, --help
Display help text and exit.
USAGE
The default behavior is to run a new command with a given affinity mask:
taskset mask command [arguments]
You can also retrieve the CPU affinity of an existing task:
taskset -p pid
Or set it:
taskset -p mask pid
PERMISSIONS
A user can change the CPU affinity of a process belonging to the same user. A user must possess CAP_SYS_NICE to change the CPU affinity of
a process belonging to another user. A user can retrieve the affinity mask of any process.
SEE ALSO chrt(1), nice(1), renice(1), sched_getaffinity(2), sched_setaffinity(2)
See sched(7) for a description of the Linux scheduling scheme.
AUTHOR
Written by Robert M. Love.
COPYRIGHT
Copyright (C) 2004 Robert M. Love. This is free software; see the source for copying conditions. There is NO warranty; not even for MER-
CHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
AVAILABILITY
The taskset command is part of the util-linux package and is available from https://www.kernel.org/pub/linux/utils/util-linux/.
util-linux August 2014 TASKSET(1)