BUG #17307: Performance deviation between the multiple iterations (NOPM & TPM values).

The following bug has been logged on the website:

Bug reference: 17307
Logged by: HPC Researcher
Email address: researcherhpc(at)gmail(dot)com
PostgreSQL version: 14.0
Operating system: RHEL 8.4
Description:

NOPM values captured with HammerDB-v4.3 scripts (schema_tpcc.tcl and
test_tpcc.tcl ) for multiple trails.
The expected performance deviation between multiple trials should be less
than 2%

Hardware configuration
Architecture x86_64
CPU op-mode(s) 32-bit, 64-bit
Byte Order: Little Endian
CPU(s): 256
On-line CPU(s) list: 0-255
Thread(s) per core: 2
Core(s) per socket: 64
Socket(s): 2
NUMA node(s): 8
L1d cache: 32K
L1i cache: 32K
L2 cache: 512K
L3 cache: 16384K
OS: RHEL8.4
RAM SIZE:512
SSD:1TB

Postgresql.conf

autovacuum_max_workers = 16
autovacuum_vacuum_cost_limit = 3000
checkpoint_completion_target = 0.9
checkpoint_timeout = '15min'
cpu_tuple_cost = 0.03
effective_cache_size = '350GB'
listen_addresses = '*'
maintenance_work_mem = '2GB'
max_connections = 1000
max_wal_size = '128GB'
random_page_cost = 1.1
shared_buffers = '128GB'
wal_buffers = '1GB'
work_mem = '128MB'
random_page_cost = 1.1
effective_io_concurrency = 200

HammerDB Scripts
>>cat schema.tcl
#!/bin/tclsh
dbset db pg
diset connection pg_host localhost
diset connection pg_port 5432
diset tpcc pg_count_ware 400
diset tpcc pg_num_vu 50
print dict
buildschema
waittocomplete

RUN TEST on i.e. start with 1VU then 2, 4 etc
Virtual Users Trail-1(NOPM) Trail-2(NOPM) %diff
12 99390 92913 6.516752
140 561429 525408 6.415949
192 636016 499574 21.4526
230 621644 701882 12.9074