I have a 12 core Linux cpu but the load is really high on this box, hovering around 50. Post: 302916723

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Top Forums UNIX for Dummies Questions & Answers I have a 12 core Linux cpu but the load is really high on this box, hovering around 50. Post 302916723 by netnerd on Thursday 11th of September 2014 01:53:14 PM

09-11-2014

Registered User

Looks like you are running at 98% memory, but not swapping. There isn't much swap used. However you may not be getting very good file cache hits and it could be adding a bit to the load.

I hada experience with a search indexer that had 10+% improvement in performance when all the memory slots were filled v.s the same amount of memory larger dimms.

1st you need to identify your bottleneck. Memory or Disk is likely with indexers.

You get most of what you need our of sar, but you need to "tweek" sar to do disks. There is a nice site to graph it for you, but I can't post URLs.

Code:

sar -Ap

Change your sar to report every 5 minutes, instead of minutes. 10 minutes is not enough and 1 minute can be too much.

Disk I/O - to look at disk I/O, system time and I/O wait, to start to see if it a issue. You can "tweek" sar to show disks usage and it may help identify bottlenecks.
Network - look at for errors on interfaces and over bandwidth limits. Make sure you are running full deplex and the max speed you expect. Look out for things like time_waits in
Code:
```
netstat -antp
```
. There are a number or kernel tuning parms.
Memory - look at utilization and swapping. In this time, there isn't much excuse to have critical application swapping. Be carefull how you read sar, free, ... they report file cache which is tempory memory use to improve performace and is a cache so it may not be used actively. There is some tuning that can be done, depending on the application behavior and memory. Like large pages, but you need to know the behavior and the what else you need to adjust.
CPU - look at user vs system time and I/O wait.
Load - wil be shown in sar, but needs to be idenitied. top has a 'H' option to toggle between showing threads and not show them. It could be the application isn't tuned. This is a overall indication of everything

It may just be the application needs tuning. Threads, size, Garbage Collection (GC), ... If java, watch the the GCs and look at tuning it.

netnerd

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LEARN ABOUT DEBIAN

amdtemp

AMDTEMP(4)						   BSD Kernel Interfaces Manual 						AMDTEMP(4)

NAME

     amdtemp -- device driver for AMD K8, K10 and K11 on-die digital thermal sensor

SYNOPSIS

     To compile this driver into the kernel, place the following line in your kernel configuration file:

	   device amdtemp

     Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5):

	   amdtemp_load="YES"

DESCRIPTION

     The amdtemp driver provides support for the on-die digital thermal sensor present in AMD K8, K10 and K11 processors.

     For the K8 family, the amdtemp driver reports each cores' temperature through a sysctl node in the corresponding CPU devices's sysctl tree,
     named dev.amdtemp.%d.sensor{0,1}.core{0,1}.  The driver also creates dev.cpu.%d.temperature displaying the maximum temperature of the two
     sensors located in each CPU core.

     For the K10 and K11 families, the driver creates dev.cpu.%d.temperature with the temperature of each core.

BUGS

     AMD K9 is not supported because temperature reporting has been replaced by Maltese.

SEE ALSO

     sysctl(8)

HISTORY

     The amdtemp driver first appeared in FreeBSD 7.1.

AUTHORS

     Rui Paulo <rpaulo@FreeBSD.org>
     Norikatsu Shigemura <nork@FreeBSD.org>

BSD
								   April 8, 2008							       BSD