Stack Overflow
Stack Overflow

Questions tagged [numa]

NUMA stands for Non Uniform Memory Access. It is a general linux term indicating that the hardware has multiple memory nodes, and that not all processing units have equal access to all memory.

NUMA stands for Non Uniform Memory Access. It is a general linux term indicating that the hardware has multiple memory nodes, and that not all processing units have equal access to all memory.

As processors become faster and faster, proximity to memory increases in importance for overall computing performance. NUMA systems address this problem by building closer connections between specific computing resources and memory.

307 questions
11
votes
3 answers

Does gcc, icc, or Microsoft's C/C++ compiler support or know anything about NUMA?

If I have a multi-processor board that has cache-coherent non-uniform memory access ( NUMA ), i.e. separate "northbridges" with separate RAM for each processor, does any compiler know how to automatically spread the data across the different memory…
Ross Rogers
  • 23,523
  • 27
  • 108
  • 164
11
votes
1 answer

numactl --physcpubind

I was using the numactl, with --physcpubind option. manual says: --physcpubind=cpus, -C cpus Only execute process on cpus. Etc... Let's say I have NUMA system with 3 NUMA nodes, where each of them has 4 cores. NUMA node 0 has 0, 1, 2, 3 as core…
tiki
  • 419
  • 1
  • 6
  • 16
10
votes
1 answer

Your kernel may have been built without NUMA support

I have Jetson TX2, python 2.7, Tensorflow 1.5, CUDA 9.0 Tensorflow seems to be working but everytime, I run the program, I get this warning: with tf.Session() as sess: print (sess.run(y,feed_dict)) ... 2018-08-07 18:07:53.200320: E…
Greg
  • 311
  • 4
  • 5
  • 12
10
votes
1 answer

Is there NUMA next-touch policy in modern Linux

When we working on NUMA system, memory can be local or remote relative to current NUMA node. To make memory more local there is a "first-touch" policy (the default memory to node binding…
osgx
  • 90,338
  • 53
  • 357
  • 513
10
votes
2 answers

How to confirm NUMA?

How can I confirm that a host is NUMA-aware? The Oracle doc says that NUMA-awareness starts at kernel 2.6.19, but the NUMA man page says that it was introduced with 2.6.14. I'd like to be sure that a Java process started with -XX:+UseNUMA is…
Christopher Neylan
  • 8,018
  • 3
  • 38
  • 51
8
votes
1 answer

memory allocation and access on NUMA hardware

I am developing a scientific computing tool in python, that should be capable of distributing work over multiple cores in a NUMA shared memory environment. I am looking into the most efficient way of doing this. Threads are -unfortunately- out of…
gertjan
  • 843
  • 1
  • 8
  • 16
8
votes
1 answer

Memory access time slow with VirtualAllocExNuma on Windows 7/64

In our application we are running on a dual Xeon server with memory configured as 12gb local to each processor and a memory bus connecting the two Xeon's. For performance reasons, we want to control where we allocate a large (>6gb) block of memory.…
photo_tom
  • 7,292
  • 14
  • 68
  • 116
8
votes
1 answer

Mongodb in Docker: numactl --interleave=all explanation

I'm trying to create Dockerfile for in-memory MongoDB based on official repo at https://hub.docker.com/_/mongo/. In dockerfile-entrypoint.sh I've encountered: numa='numactl --interleave=all' if $numa true &> /dev/null; then set -- $numa…
mkurnikov
  • 1,581
  • 2
  • 16
  • 19
8
votes
1 answer

OpenMP: splitting loop based on NUMA

I am running the following loop using, say, 8 OpenMP threads: float* data; int n; #pragma omp parallel for schedule(dynamic, 1) default(none) shared(data, n) for ( int i = 0; i < n; ++i ) { DO SOMETHING WITH data[i] } Due to NUMA, I'd like to…
user2052436
  • 4,321
  • 1
  • 25
  • 46
8
votes
3 answers

NUMA Get Current Node/Core

I'm using libnuma on Linux. My threads should be aware of the node/core they're running on. Is it possible to get the current threads's node/core somehow? I've been through the documentation, but I didn't find such a function...
Lovro
  • 712
  • 1
  • 10
  • 20
8
votes
2 answers

OpenMP and NUMA relation?

I have a dual socket Xeon E5522 2.26GHZ machine (with hyperthreading disabled) running ubuntu server on linux kernel 3.0 supporting NUMA. The architecture layout is 4 physical cores per socket. An OpenMP application runs in this machine and i have…
labotsirc
  • 722
  • 7
  • 21
7
votes
0 answers

NUMA node tensorflow negative one value

I built tensorflow from sources using bazel and when I finally open a session, I get the following warning: 2017-05-07 15:45:40.816127: I tensorflow/stream_executor/cuda/cuda_gpu_executor.cc:893] successful NUMA node read from SysFS had negative…
Sarthak Mittal
  • 154
  • 3
  • 9
7
votes
1 answer

NUMA awareness of JVM

My question concerns the extent to which a JVM application can exploit the NUMA layout of a host. I have an Akka application in which actors concurrently process requests by combining incoming data with 'common' data already loaded into an immutable…
Pengin
  • 4,692
  • 6
  • 36
  • 62
7
votes
5 answers

many-core CPU's: Programming techniques to avoid disappointing scalability

We've just bought a 32-core Opteron machine, and the speedups we get are a little disappointing: beyond about 24 threads we see no speedup at all (actually gets slower overall) and after about 6 threads it becomes significantly sub-linear. Our…
Tim Cooper
  • 10,023
  • 5
  • 61
  • 77
7
votes
1 answer

NUMA Memory Page Migration Overhead

I have to find the overhead associated with NUMA memory page migration under Linux. Can you please tell me which tools I can use? If possible could you show an example.
user1450099
  • 71
  • 1
  • 2
1
2
3
…
20 21