107 votes
Accepted

On a dual CPU server, is it normal for one CPU to run hotter than the other?

The problem ended up being a poorly fit heatsink. Maybe poorly fit isn't the right description. Turns out, you have to put thermal paste on the heatsink, not the plastic cover that goes over the ...
  • 1,943
35 votes
Accepted

How are CPU time and CPU usage the same?

CPU time is allocated in discrete time slices (ticks). For a certain number of time slices, the CPU is busy, other times it is not (which is represented by the idle process). In the picture below the ...
  • 82.2k
30 votes

How do I track CPU Utilization for Window Services?

Here's how to get detail on a service without any external tools on Windows 7, 8 and 10: Open the Resource Monitor: Open Task Manager and click on the Performance tab Click on "Open Resource ...
27 votes
Accepted

Is it possible to influence the way CPUs are enumerated under Linux?

Wut?!? This is crazy, you know? It's unsupported and likely not good for your hardware. You should be using equally-spec'd processors in your server. I suppose you couple simply execute your ...
  • 195k
25 votes

On a dual CPU server, is it normal for one CPU to run hotter than the other?

In my experience, it is normal for paired components in a case to run at different temperatures, because airflow is not the same everywhere. Here's a graph of HDD temperature from my colo box. The ...
  • 78.5k
23 votes
Accepted

Why CPU spent time on IO(wa)?

The CPU idle status is divided in two different "sub"-states: iowait and idle. If the CPU is idle, the kernel then determines if there is at least one I/O currently in progress to either a local disk ...
  • 1,445
17 votes
Accepted

Proper way of interpreting system load on a 4 core 8 thread processor

Not surely, but mostly on 1.00*n_cpu. The load means the following: if there are multiple processes on a single-cpu system, they are running seemingly parallel. But it is not true. What practically ...
  • 4,914
15 votes

How are CPU time and CPU usage the same?

The CPU time is the time that the process is using the CPU - converting it to a percentage is done by dividing by the amount of real time that's passed. So, if I have a process that uses 1 second of ...
14 votes

How to tell if a Linux system is big endian or little endian?

You can take advantage of ELF file format to determine the endianness of your system. For example, print the first six bytes of an arbitrary ELF file in hex: xxd -c 1 -l 6 /bin/ls 0000000: 7f . ...
  • 241
14 votes

difference between taskset and cpuset

Taskset is for binding a process to one or more CPUs; essentially specifying where it can run at initial execution or while it's running. If using RHEL/CentOS on modern server equipment, numactl is ...
  • 195k
12 votes
Accepted

ESXi and Windows Server CPU parking

Definitely try to right-size your VMs. If you have enough free virtual CPUs to be concerned about "CPU parking", you may have too many allocated to the VM. It's not a common request, so I'd just ...
  • 195k
11 votes

Can I safely mix RAM (ECC) sizes in a server board?

The general answer is "yes", but you need to be careful. The issue is not so much in mixing different sizes of RAM (I was doing that here for a while on a very similar motherboard), but with other ...
10 votes
Accepted

Do I need a CPU that supports Virtuallization to do Containerization?

But do I need a CPU that supports virtualization to run containerization such as Docker, or since it runs an app using the OS's libraries in a container, can I just run it on a CPU without ...
  • 41.3k
10 votes

Intel Xeon processors: Difference between 2S/4S and S2S/S4S scalability

Based on "6.5.8.4 MPSUP: Multiprocessor Support" in Intel® Xeon® Processor E7-4800/8800 v3 Product Families; Datasheet - Volume 1: Electrical, Mechanical and Thermal (pdf, page 139): This location ...
  • 201
10 votes
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Intel Xeon processors: Difference between 2S/4S and S2S/S4S scalability

The difference between S4S and 4S is the number of QPI-Links. 4S has 2 links per CPU, S4S and S8S have 3. On a 4S system CPUs form a ring, which means for every CPU there is another CPU with which it ...
9 votes

vCPU performance between 1 or 2 vCPU's

Not considerable enough to make an impact. The adjustments are more for licensing. For example, Windows Server is licensed per processor slot, so you'd pay more to have 1 core and 4 CPUs than to have ...
  • 14.9k
9 votes

Linux: Why does the CPU frequency fluctuate when using the performance governor?

After some experimentation, I think I can answer my own question. As mentioned in this thread, on certain Intel hardware, there are two ways to manage the CPU frequency: Using pstate. Using regular ...
9 votes
Accepted

How to check if RAM is running in ECC mode?

Today I found out that there is a commercial version of memtest86 (without the +) from PassMark that offers a free version too which thankfully included ECC-Checks. In addition it also supports DDR4 ...
  • 1,451
8 votes

On a dual CPU server, is it normal for one CPU to run hotter than the other?

It is not. Unless you have some serious issues with the airflow. Or one of the coolers is bad. Temperature WILL vary - but not that much (70 vs. 15 degree celsius). Given how low 15 degree is I would ...
  • 50.9k
8 votes

ESX 5.5 with enterprise plus license but can not add more than 32 vcpu per vm

Make sure you're using the vSphere Web Client to do this and have updated VM hardware versions... But I should warn you... Making a virtual machine with more than 32 vCPU is probably a bad idea. ...
  • 195k
8 votes
Accepted

How can I tell the maximum threads my server can run?

Welcome to ServerFault! You have two CPU sockets, that is two physical processors. Each processor has 10 cores, each core being basically equivalent to a classic single-core CPU on its own. Each core ...
  • 4,153
7 votes
Accepted

How does Linux distribute load on multiple CPU cores

A good answer to your question is much too complicated for SF. A short answer would be "yes", Linux and most modern OSes balance processes that are ready to run across available processors very ...
  • 77.4k
7 votes
Accepted

Desktop CPU VS server CPU performance - is passmark relevant?

In general server-grade hardware will perform better than desktop-grade equivalents when under load from multiple processes (e.g. running several services serving requests, hosting multiple users, etc)...
  • 960
7 votes

How is NUMBER_OF_PROCESSORS env variable generated?

As far as I know, $ENV:NUMBER_OF_PROCESSORS is derived from WMI, using: Win32_ComputerSystem.NumberOfLogicalProcessors To add to the confusion, Win32_ComputerSystem also reports the number of ...
7 votes
Accepted

What is a core, and will purchasing more cores for my VPS speed up page load times?

You might know what a core is from shopping for desktops and laptops. It's the CPU, the processor, the bit that does the work. Here's a wikipedia link that might help. I plugged your site into this ...
7 votes

CPU load for high performance computing

Load average shows the queue of threads ready to run. In Linux, this includes also threads waiting for disk. It could happen that a broken NFS server could increase the load average to insane numbers. ...
6 votes

TrustedInstaller.exe Takes a lot of Memory in Windows Server 2008

I was looking into this recently on a 2008 R2 server and below is what I found: To see if trustedinstaller is doing anything have a look at c:\windows\logs\cbs\cbs.log. If everything's good ...
6 votes
Accepted

KVM: Which CPU for VM ('host' vs 'kvm64') to use for web load?

The Proxmox wiki addresses the issue of which CPU type to choose, in part: Qemu can emulate a number different of CPU types from 486 to the latest Xeon processors. Each new processor generation adds ...
6 votes
Accepted

how to know if my servers should use huge pages ( memory page size )

Hugepages are interesting when applications need large mappings that they will do random accesses to, because that is the worst possible case for the Translation Lookaside Buffer (TLB). You trade off ...
6 votes

Why are server CPUs so weak and expensive?

So let's go through your opinions line-by-line then; So looking at CPUs with good single core performance. One example would be AMD EPYC 73F3 which is (according to passmark) on par with Ryzen 5950X, ...
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