I have a script that outputs my overall cpu usage. But if I compare this to the Task Manager, I get a different number. Is my script just wrong or is there a better way to do it?
$cpu = Get-WmiObject win32_processor
logwrite $cpu.LoadPercentage
Task Manager says 26% while the output file says 1%. My script says 0%, 1% or 2% most of of the time.
The reason being, CPU Usage fluctuates with each passing moment, and that is reflected in your task manager. If you see your task manager the CPU usage will be fluctuating every time.
$cpu.LoadPercentage from your script gives you the CPU usage at the time of creation of your output file. Hence, you see the anomalies. You should be looking for a more dynamic way of getting CPU usage or getting it in intervals.
Related
I am using PowerShell for some benchmarking of Autodesk Revit, and I would like to add some resource monitoring. I know I can get historical CPU utilization and RAM utilization in general, but I would like to be able to poll Process specific CPU and RAM utilization every 5 seconds or so.
In addition, I would love to be able to poll how many cores a process is currently using, the clock speed of those specific cores, and the frame rate of the screen that process is currently displayed on.
Are those things even accessible via PowerShell/.NET? Or is that low level stuff I just can't get to with PS?
can anyone have an idea about my question.
I need to know about how task manager assign priorities in windows.
It is all about the scheduler, in an OS you have a lot of things running "at the same time", actually there is a scheduler giving access to the CPU to a certain process, while a process is waiting for the CPU it gains "points", then the scheduler gives the CPU to the highest amount of points (that is what I was teached).
The priority will make the process gain more or less points while it is waiting.
i have developed a script for data extraction in perl.
using a parallel::ForkManager module and its functionalities
it works well when i run the script from 4core cpu.
but when i try to run it from different cpu which is of 2core only has a cpu usage 100%.
my problem is to reduce that cpu usage n run script smoothly.
i already reduces the max_Child_process to 10 previously it was 40.
restriction: my script must parse all pages and store data in database within a 25 seconds.
currently it is doing it in 22-24 seconds but uses full cpu. can anybody gives me some idea about how and what to do for reducing my cpu usage.
Use a usleep when waiting for child processes.
until (waitpid(-1, WNOHANG)) {
usleep(100);
}
Dramatically reduces cpu in parallel programs
Could anyone point to me what is the overhead of running a matlabpool ?
I started a matlabpool :
matlabpool open 132procs 100
Starting matlabpool using the '132procs' configuration ... connected to 100 labs.
And followed cpu usage on the nodes as :
pdsh -A ps aux |grep dmlworker
When I launch the matlabpool, it starts with ~35% cpu usage on average and when the pool
is not being used it slowly (in 5-7 minutes) goes down to ~2% on average.
Is this normal ? What is the typical overhead ? Does that change if matlabpooljob is launched as a "batch" job ?
This is normal. ps aux reports the average CPU utilization since the process was started, not over a rolling window. This means that, although the workers initialize relatively quickly and then become idle, it will take longer for this to reflect in CPU%. This is different to the Linux top command, for example, which will reflect the utilization since the last screen update in %CPU.
As for typical overhead, this depends on a number of factors: clearly the number of workers, the rate and data size of jobs submitted (as well as in maintaining the worker processes, there is some overhead in marshalling input and output, which is not part of "useful computation"), whether the Matlab pool is local or attached to a job manager, and the Matlab version and O/S.
From experience, as a rough guide on a modern *nix server, I would think an idle worker should be not be consuming more than 20% of a single core (e.g. <~1% total CPU utilization on a 16-core box) after initilization, unless there is a configuration issue. I should not expect this to be influenced by what kind of jobs you are submitting (whether using "createJob" or "batch" or "parfor" for example): the workers and communication mechanisms underneath are essentially the same.
Does using the computer for something else while benchmarking ( with the Benchmark module ) have an influence on the benchmark results?
Yes, it does. This running perl process complies with general process management rules your OS does. OS process scheduler will distribute CPU time amongst all running processes.
There is a way you can influence this distribution - nice command. It can be used to set process priority value, so the scheduler can give such process more CPU time.
The lesser nice priority value, the more CPU time the process will get.
For exmaple command nice -n -20 ./benchmark.pl will get almost all CPU time