Background
Reading through database documentation and understanding that some database platforms do not really support NUMA, as well as others.
What is NUMA?
Wikipedia
Modern CPUs operate considerably faster than the main memory they use.
CPUs increasingly have found themselves “starved for data” and having to stall while waiting for data to arrive from memory.
Many supercomputer designs of the 1980s and 1990s focused on providing high-speed memory access as opposed to faster processors, allowing the computers to work on large data sets at speeds other systems could not approach.
Limiting the number of memory accesses provided the key to extracting high performance from a modern computer.
For commodity processors, this meant installing an ever-increasing amount of high-speed cache memory and using increasingly sophisticated algorithms to avoid cache misses.
But the dramatic increase in size of the operating systems and of the applications run on them has generally overwhelmed these cache-processing improvements. Multi-processor systems without NUMA make the problem considerably worse. Now a system can starve several processors at the same time, notably because only one processor can access the computer’s memory at a time.
NUMA attempts to address this problem by providing separate memory for each processor, avoiding the performance hit when several processors attempt to address the same memory.
For problems involving spread data (common for servers and similar applications), NUMA can improve the performance over a single shared memory by a factor of roughly the number of processors (or separate memory banks).
Of course, not all data ends up confined to a single task, which means that more than one processor may require the same data. To handle these cases, NUMA systems include additional hardware or software to move data between memory banks.
This operation slows the processors attached to those banks, so the overall speed increase due to NUMA depends heavily on the nature of the running tasks.
Linux
Review Configuration
Processor Name
Get Processor Name
/proc/cpuinfo
Code
cat /proc/cpuinfo | grep -i "model name" | sort | uniq
Output
Processors / CPU
Get Number of CPUs and Cores
Number of Cores
/proc/cpuinfo
Code
cat /proc/cpuinfo | grep -c 'core'
Output
Number of processors
/proc/cpuinfo
Number of processors
Code
cat /proc/cpuinfo | grep -c 'processor'
Output
Number of Sockets
lscpu
Number of sockets
Code
lscpu | grep -i 'socket'
Output
NUMA Grouping
Get CPU NUMA grouping
lscpu
Code
lscpu | grep -i 'NUMA'
Output
Explanation
- Here we have a lone NUMA Group
- All six (6) CPUs are within the lone grouping
numactl
Code
numactl -- hardware
Output
Explanation
- Single NUMA Node
- CPUs => 0,1,2,3,4,5
- Size => 132 GB
- free => 600 MB
