8
votes
NUMA CPU numbering in Linux
Stop the grepping and uniq and run lscpu and lstopo --of png > server.png and visualize the results...
[root@LA_Specialty ~]# lscpu
Architecture: x86_64
CPU op-mode(s): 32-bit, 64-...
- 198k
6
votes
Accepted
DL380 Gen9 which processor and what impact on NUMA
Good question.
This is going to depend on your application and how much RAM is needed. I come from the Linux and VMware worlds where the applications/OS are NUMA aware.
HP have a guide on NUMA ...
- 198k
5
votes
Is a machine with a single NUMA node, actually a regular (non-NUMA) system?
Modern x86 CPU architectures (AMD Opteron and later and Intel Nehalem-based Xeon and later) are NUMA capable, but they do not necessarily require to work in NUMA mode.
In your specific case, you have ...
- 50.7k
4
votes
Accepted
Is NUMA always completely NUMA or are there also hybrid systems?
No, a NUMA system is a NUMA system, there are nodes (generally CPUs), each node has it's own memory - most modern OS's will try to ensure that all memory allocations to a process are on the same node ...
- 102k
4
votes
Accepted
ZFS on Linux and KVM: NUMA nodes for host
Manually pinning resources/processes to specific sockets its something that should be only done in very specific circumstances. Moreover, ARC itself is a global resource with (mostly) unpredictable ...
- 50.7k
4
votes
Recommended NUMA nodes per socket on dual AMD Epyc 7643 server with 1TB of RAM
What do you suggest to set the NUMA nodes per socket to?
The number of actual NUMA nodes on your system - it should be set to that and nothing else. You don't mention your system layout or any other ...
- 102k
3
votes
Accepted
Latency of memory accesses via interconnectors
Your single node numbers of 90 ns local vs 370 ns other socket seems reasonable. However, I think the 600 ns of Infiniband is supposed to be end to end, through a switch to a different frame.
600 ns ...
- 33.3k
3
votes
Accepted
Ryzen Threadripper CPU does not report multiple NUMA nodes
Check your Bios.
Threadripper has two work modes. Your bios sets it in Unified Memory Access Mode.
Not using that particualar board - so no ideea how they name the setting.
Note that the platform ...
- 51.9k
2
votes
Change the NUMA node where a PCIe device is attached
It's hardwired and wouldn't be changeable via software.
What problem are you looking to solve?
- 198k
2
votes
NUMA CPU numbering in Linux
lscpu [1] will more concisely express the numa layout of each system. lstopo [2] gives a hierarchic view of the processor relations.
Enumeration is determined by CPU + BIOS + kernel. At a high level, ...
- 5,173
2
votes
Virtualbox performance on NUMA host (AMD Epyc)
Do not oversubscribe CPU. That is, by default, do not assign total guest CPUs more than the number of physical cores. Performance will degrade, sometimes buy a little, but sometimes severely.
NUMA ...
- 33.3k
2
votes
Hyper-V: Not enough memory to start VM although there are plenty left
You ran out of memory. You have to reserve some for the host and other processes, and 2.5G isn't much for Windows as a hypervisor. Just because memory is free doesn't mean it isn't subject to resident ...
- 7,136
2
votes
Accepted
Does disabling "numa interleave" from bios cause memory page-out(when cpu-1 has no free memory left) to hdd on all dual-cpu systems?
Disabling node interleave in the BIOS doesn't cause your system to swap.
It would be more accurate to say that disabling this option puts NUMA interleaving under OS control. This option exists for ...
- 248k
2
votes
Incorrect # of Hugepages in `numstat`
Huge pages on Linux isn't the easiest to understand. Especially when some tools show things others do not, and everyone's doing their own unit conversions.
System wide /proc/meminfo will show the sum ...
- 33.3k
1
vote
NPS4 on a Threadripper 3960x gives two nodes with no memory at all
Ryzen 5 3960x is a desktop part. There are not the same quality of balanced memory guides like there are for EPYC server CPUs. On EPYC, memory is really in quadrants of memory channel pairs. Not ...
- 33.3k
1
vote
DELL PowerEdge R740xd - NUMA - memory performance
This is obviously a late answer but I ran across this question. I specialize in doing a lot of this at work and unfortunately a complete answer on doing NUMA testing is long and nuanced. Here are some ...
- 1,108
1
vote
Accepted
Incorrect # of Free Hugepages in `numastat`
HugePages_Total and HugePages_Free units are pages, in this case 2MB pages. See Documentation/vm/hugetlbpage.txt. (Two significant digits are slightly misleading, page counts are integers.)
Note that ...
- 33.3k
1
vote
Opteron 6274 Cache Differs from Manufacturer's Specs in Windows Server 2016
HT assist is turned on in the bios. it uses cache to help speed up access.On my system it uses 4MB per cpu (16MB - 4MB = 12MB). 12MBx4 = 48MB.
Turn HT assist off in the bios, and you will see more L3 ...
1
vote
NUMA placement failed, performance might be affected
I was getting this message on Debian when I forgot to limit Dom0 memory.
For GRUB2 add or edit the following line in the /etc/default/grub file:
GRUB_CMDLINE_XEN_DEFAULT="dom0_mem=512M,max:512M"
More ...
- 11
1
vote
What does `numactl --localalloc` do?
My understanding of the documentation is that --localalloc will allocate memory on the node of the CPU that made the system call. This should work well for applications that have worker threads pinned ...
- 235
1
vote
What is NUMA node limit in modern Windows OS
HP Sold an Itanium-based 64-socket/NUMA-node Integrity server that ran Windows Server 2003 for Itanium and Server 2008R2 supports 64 x64 sockets/NUMA nodes, I can't find any details for Server 2012R2 ...
- 102k
1
vote
Is NUMA always completely NUMA or are there also hybrid systems?
Since I cannot comment yet...
All memory is NUMA memory but you can hack your code to leverage locality in memory that is you can pin some applications on CPUs that have memory required to run those ...
- 21
1
vote
Hyper-V NUMA setting
Guest Aware NUMA should actually improve performance of NUMA-aware guest OSs and applications, such as Windows Server and SQL Server.
See here for lots of details: https://technet.microsoft.com/en-us/...
- 211
1
vote
Hyper-V NUMA setting
When you click "Use Hardware Topology" the VM assumes the same configuration reported by the BIOS of the physical machine. If it then said that your VM had 24 NUMA nodes, that means your host's BIOS ...
- 5,176
1
vote
How would I know if I should be disabling virtual NUMA on VMs running older applications?
The article: "NUMA Deep Dive Part 1: From UMA to NUMA" recommends "Intel Memory Latency Checker v3.5", a shorter article "VMware vSphere — Why checking NUMA Configuration is so important!" (from where ...
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