Re: pgsql: Introduce pg_shmem_allocations_numa view

On 2025-Jun-25, Tomas Vondra wrote:

> Not sure. I thought NUMA doesn't matter very much on 32-bit systems too,
> exactly because those systems tend to use small amounts of memory. But
> then while investigating this issue I realized even rpi5 has NUMA, in
> fact it has a whopping 8 nodes:
>
> debian(at)raspberry-32:~ $ numactl --hardware
> available: 8 nodes (0-7)

Interesting. Mine only shows a single node.

alvherre(at)amras:~ $ uname -a
Linux amras 6.12.25+rpt-rpi-2712 #1 SMP PREEMPT Debian 1:6.12.25-1+rpt1 (2025-04-30) aarch64 GNU/Linux
alvherre(at)amras:~ $ sudo numactl --hardware
available: 1 nodes (0)
node 0 cpus: 0 1 2 3
node 0 size: 8051 MB
node 0 free: 202 MB
node distances:
node 0
0: 10
alvherre(at)amras:~ $ sudo lscpu
Architecture: aarch64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
CPU(s): 4
On-line CPU(s) list: 0-3
Vendor ID: ARM
Model name: Cortex-A76
Model: 1
Thread(s) per core: 1
Core(s) per cluster: 4
Socket(s): -
Cluster(s): 1
Stepping: r4p1
CPU(s) scaling MHz: 62%
CPU max MHz: 2400.0000
CPU min MHz: 1500.0000
BogoMIPS: 108.00
Flags: fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp
asimdhp cpuid asimdrdm lrcpc dcpop asimddp
[...]
NUMA:
NUMA node(s): 1
NUMA node0 CPU(s): 0-3

Did you enable something special on it maybe?

... Oh, I found this:
https://www.jeffgeerling.com/blog/2024/numa-emulation-speeds-pi-5-and-other-improvements
Sounds like you have this in your system and I don't in mine.

--
Álvaro Herrera PostgreSQL Developer — https://www.EnterpriseDB.com/