I want to test performance of one of my other program with different memory load like 10%, 20%, 30% etc. To generate memory load , I used stress tool.
When I execute
stress -m 1 --vm-bytes 128M
or
stress -m 1 --vm-bytes 256M
top command shows
% CPU %Memory
99 5 - 10%
Maximum 10% memory load was generating, not exceeding any more.
How to generate 20%, 30% memory load?
Is there any other tool available for generating memory load in linux
When I try to restrict CPU utilization using cpulimit, it doesn't change the CPU utilization.
cpulimit -p <pid> -l 20
Is it possible to restrict CPU utilization and memory load at the same time - like 10% CPU Utilization, 10% Memory, 10 % CPU Utilization, 50% Memory load ?
I am using Intel(R) Core(TM) i7-3770 CPU # 3.40GHz, Ubuntu 12.04.5 LTS , 2GB RAM, 8 CPU core.
Related
I'm using stress-ng and not able to reach 100% cpu load. stress-ng, version 0.09.60 on kernel 4.1.35 a quad core ARM processor. I've used the following commands:
stress-ng --matrix 4 --tz --ignite-cpu
I noticed that the cpu climbs up in 25% increments to 75% when I use the following:
stress-ng --matrix 1 --tz --ignite-cpu → 25% cpu load
stress-ng --matrix 2 --tz --ignite-cpu → 50% cpu load
stress-ng --matrix 3 --tz --ignite-cpu → 75% cpu load
Any higher matrix number of workers does not increase the load, for example
stress-ng --matrix 10 --tz --ignite-cpu → 75% cpu load
I've also tried as referenced
stress-ng -c 4 -l 100 or stress-ng -c 0 -l 100 and it still doesn't go above 75%. In fact those --cpu-load options don't keep cpu up as consistently as --matrix option.
I wonder if you want to use dd to increase CPU benchmark. I usually use it to test CPU usage alarm.
dd if=/dev/zero of=/storage/test bs=1M count=1024 | md5sum
ref: How to use 'dd' to benchmark your disk or CPU?
Perhaps not many people use this, but 'dd' in conjunction with any stream-processing CPU-intensive program can also be used as a simple CPU benchmark! It may be not very accurate, but the huge advantage is that it doesn't require installing any additional software whatsoever, and typically you can run this “out of the box” on any GNU/Linux system.
I'm really confused. Why does the load average and %CPU does not match the process CPU usage below. It seems like the process is eating up a lot of CPU while the AWS EC2 meters only says 25% CPU is used.
%CPU -- CPU Usage : The percentage of your CPU that is being used by the process. By default, top displays this as a percentage
of a single CPU. On multi-core systems, you can have percentages
that are greater than 100%. For example, if 3 cores are at 60% use,
top will show a CPU use of 180%.
You can toggle this behavior by hitting Shift+i while top is running to show the overall percentage of available
CPUs in use.
load average: 22.56, 24.99, 26.51
From left to right, these numbers show you the average load over the last 1 minute, the last 5 minutes, and the last 15 minutes.
us -- User CPU time
The time the CPU has spent running users' processes that are not niced.
sy -- System CPU time
The time the CPU has spent running the kernel and its processes.
ni -- Nice CPU time
The time the CPU has spent running users' proccess that have been niced.
wa -- iowait
Amount of time the CPU has been waiting for I/O to complete.
hi -- Hardware IRQ
The amount of time the CPU has been servicing hardware interrupts.
si -- Software Interrupts
The amount of time the CPU has been servicing software interrupts.
st -- Steal Time
The amount of CPU 'stolen' from this virtual machine by the hypervisor for other tasks (such as running another virtual machine).
See more details from In Linux “top” command what are us, sy, ni, id, wa, hi, si and st (for CPU usage).
after you run command "top" you can press "1" on your keyboard to see individual CPU utilization, more details when you run command "man top"
Note process "msqld" can use CPU from several resources and its utilization % could easily go beyond 100% in "top" display.
Hi maybe your app using single core and other cores are free. I think your instance has 4 CPU core and one is utilizing 100%. can you please check utilization by each core.
I have compiled a weather forecasting software with openmpi in double precision on Ubuntu 14.04 and Intel ifort compiler. However I am not able to figure out few issues. I need to figure out the number of processors I need to send to mpirun. This is the output of lscpu
x86_64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
CPU(s): 4
On-line CPU(s) list: 0-3
Thread(s) per core: 2
Core(s) per socket: 2
Socket(s): 1
NUMA node(s): 1
Vendor ID: GenuineIntel
CPU family: 6
Model: 60
Stepping: 3
CPU MHz: 800.000
BogoMIPS: 6784.93
Virtualization: VT-x
L1d cache: 32K
L1i cache: 32K
L2 cache: 256K
L3 cache: 3072K
NUMA node0 CPU(s): 0-3output of lscpu
This is the command that I am using to run my software
mpirun -np 4 aaa. But When I do this I get these errors -
MPI_ABORT was invoked on rank 0 in communicator MPI_COMM_WORLD
with errorcode 1001.
NOTE: invoking MPI_ABORT causes Open MPI to kill all MPI processes.
You may or may not see output from other processes, depending on
exactly when Open MPI kills them.
When I set np to 1 it runs successfully but does not use the CPU completely. CPU usage varies from 3% to 35% but the memory usage is almost 100% and the system freezes for about ten minutes and exits with the error message
forrtl severe(41) insufficient virtual memory.
I have run WRF (the software associated with this question is not WRF) with multiple semaphores and I have not experienced any speed or memory issues.
I could recompile to single precision but before I do that I want to be able to figure out the number of cores(processors) to be sent to mpirun.
Most Intel CPUs (including the one you are using) have a virtual execution unit that allows two simultaneous instruction streams commonly called "hyperthreading." To the Linux kernel, this appears as an extra CPU core. Hence, lscpu tells you there are four CPU cores (CPU(s): 4). Looking carefully at the rest of the output, you will see that there are, in fact, only two CPU cores:
Thread(s) per core: 2 <--- this is hyperthreading
Core(s) per socket: 2
Socket(s): 1
I don't generally recommend running multiple MPI processes on a single physical CPU core even if there is hyperthreading. It tends to lead to detrimental performance, and, in your case, sometimes crashes. Try using mpiexec -np 2 aaa and see what happens. If it crashes again, there is something else wrong.
When I set np to 1 it runs successfully but does not use the CPU completely. CPU usage varies from 3% to 35% but the memory usage is almost 100% and the system freezes for about ten minutes and exits with the error message forrtl severe(41) insufficient virtual memory.
You may need to run a smaller problem size. This machine doesn't have enough physical memory to satisfy the requested allocations and is using virtual memory (essentially hard disk space) to try to fulfill them, but still running out. In any case, you don't want to be using virtual memory when running a simulation (it's ~1000x slower than main memory which is already slow).
I have a quad core (with hyper threading Technology - HT)
I'm running an application which takes 270% CPU (according to TOP command)
What is the total available CPU usage? (is it 400% or 800%?)
I'm asking because according to Intel documentation, the HT can up the performance up to 30% cpu, so 800% seem to much, yeah?)
What is the relation between load averages and CPU usage?
1: 800. You have 8 cores visible to the OS - that they are not real cores (due to hyperthreading limitations) is not of concern.
2: Ever bothered reading documentation? Practically there is no relation between load average and CPU uage. Load average is "waiting processes" but that can mean they are waiting for IO, and the CPU may not be busy.
I'm having some performance issue on my embedded device:
# uptime
14:59:39 up 5:37, load average: 1.60, 1.50, 1.53
Very bad for a monocore system ... :-p! However if I check with the top utility, I always have an idle time around 80% !
Mem: 49020K used, 75960K free, 0K shrd, 0K buff, 21476K cached
CPU: 12.5% usr 4.8% sys 0.0% nic 81.7% idle 0.0% io 0.9% irq 0.0% sirq
Load average: 1.30 1.42 1.51 1/80 18696
After reading some articles, I would better believe the uptime command. But why this difference? Is my CPU really idle ??!
Load is not just a measure of how many processes in the R state (runnable, could use CPU time), but also processes in the D state (uninterruptable sleep, usually waiting for IO). You likely have a process in the D state which is contributing to load, but not using cpu. This command would show you all the current processes which are contributing to load:
ps aux | awk '$8~/[RD]/'
Have a look at that output and see if you have commands in the D state (in the 8th column)
you'd better to learn what 'load average' stands for.
in short, it's a number of processes, waiting for some resource, and the resource may be CPU, HDD, serial port, ...
The Load average seems a little high, that could meen that the cpu is busy with things like I/O(disk/network) or thread managment(you may have too meny running).