OK, so you installed AIX 7.2 TL2 SP2 on an LPAR running on your shiny, new POWER9 system.
# oslevel -s
7200-02-02-1810
# lsconf
System Model: IBM,9009-22A
Machine Serial Number: 9999999
Processor Type: PowerPC_POWER9
Processor Implementation Mode: No Data Available
Processor Version: No Data Available
Number Of Processors: 2
Processor Clock Speed: 2500 MHz
CPU Type: 64-bit
Kernel Type: 64-bit
LPAR Info: 48 l0790p046
Memory Size: 4096 MB
Good Memory Size: 4096 MB
Platform Firmware level: VL910_059
Firmware Version: IBM,FW910.00 (VL910_059)
Console Login: enable
Auto Restart: true
Full Core: false
NX Crypto Acceleration: Capable and Enabled
…
# lparstat -i
Node Name : orion
Partition Name : orion
Partition Number : 48
Type : Shared-SMT-4
Mode : Uncapped
Entitled Capacity : 0.40
Partition Group-ID : 32816
Shared Pool ID : 0
Online Virtual CPUs : 2
Maximum Virtual CPUs : 2
Minimum Virtual CPUs : 1
Online Memory : 4096 MB
Maximum Memory : 4096 MB
Minimum Memory : 1024 MB
Variable Capacity Weight : 128
Minimum Capacity : 0.10
Maximum Capacity : 0.40
Capacity Increment : 0.01
Maximum Physical CPUs in system : 20
Active Physical CPUs in system : 20
Active CPUs in Pool : 20
Shared Physical CPUs in system : 20
Maximum Capacity of Pool : 2000
Entitled Capacity of Pool : 2000
Unallocated
Capacity
:
0.00
Physical CPU Percentage : 20.00%
Unallocated Weight : 0
Memory Mode : Dedicated
Total I/O Memory Entitlement : -
Variable Memory Capacity Weight : -
Memory Pool ID : -
Physical Memory in the Pool : -
Hypervisor Page Size : -
Unallocated Variable Memory Capacity Weight: -
Unallocated I/O Memory entitlement : -
Memory Group ID of LPAR : -
Desired Virtual CPUs : 2
Desired Memory : 4096 MB
Desired Variable Capacity Weight : 128
Desired Capacity : 0.40
Target Memory Expansion Factor : -
Target Memory Expansion Size : -
Power Saving Mode : Dynamic Power Savings (Favor Performance)
Sub Processor Mode : -
Then, IBM released AIX 7.2 TL3 (last week). Before applying the new TL, you did a little research and reading about TL3. You find the following information:
“For POWER9
technology-based servers, the default SMT setting for AIX 7.2 TL 3 has
been changed to SMT8 to provide the best out-of-the-box performance
experience. For POWER8 technology-based servers, the default SMT setting
remains SMT4.”
https://www-01.ibm.com/common/ssi/cgi-bin/ssialias?infotype=AN&subtype=CA&htmlfid=897/ENUS218-381&appname=USN
You check your current, TL2 system, and find that you have the default SMT setting in the LPAR i.e. SMT4.
# smtctl
This system is SMT capable.
This system supports up to 8 SMT threads per processor.
SMT is currently enabled.
SMT boot mode is not set.
SMT threads are bound to the same virtual processor.
proc0 has 4 SMT threads.
Bind processor 0 is bound with proc0
Bind processor 1 is bound with proc0
Bind processor 2 is bound with proc0
Bind processor 3 is bound with proc0
proc8 has 4 SMT threads.
Bind processor 4 is bound with proc8
Bind processor 5 is bound with proc8
Bind processor 6 is bound with proc8
Bind processor 7 is bound with proc8
OK, fine. So will my SMT setting really change, from 4 to 8, after I install TL3? Well, let’s find out.
You apply TL3 and reboot the LPAR. ‘Lo and behold’, the LPAR has automatically changed from SMT4 to SMT8. Wow!
# oslevel -s
7200-03-01-1838
# uptime
11:01PM up 1 min, 1 user, load average: 2.12, 0.75, 0.28
# smtctl
This system is SMT capable.
This system supports up to 8 SMT threads per processor.
SMT is currently enabled.
SMT boot mode is not set.
SMT threads are bound to the same virtual processor.
proc0 has 8 SMT threads.
Bind processor 0 is bound with proc0
Bind processor 1 is bound with proc0
Bind processor 2 is bound with proc0
Bind processor 3 is bound with proc0
Bind processor 4 is bound with proc0
Bind processor 5 is bound with proc0
Bind processor 6 is bound with proc0
Bind processor 7 is bound with proc0
proc8 has 8 SMT threads.
Bind processor 8 is bound with proc8
Bind processor 9 is bound with proc8
Bind processor 10 is bound with proc8
Bind processor 11 is bound with proc8
Bind processor 12 is bound with proc8
Bind processor 13 is bound with proc8
Bind processor 14 is bound with proc8
Bind processor 15 is bound with proc8
Also, you notice that the processor implementation type and
version, are now reporting correctly! Before TL3, they both reported
‘No Data Available’ with lsconf.
# lsconf
System Model: IBM,9009-22A
Machine Serial Number: 9999999
Processor Type: PowerPC_POWER9
Processor Implementation Mode: POWER 9
Processor Version: PV_9_Compat
Number Of Processors: 2
Processor Clock Speed: 2500 MHz
CPU Type: 64-bit
Kernel Type: 64-bit
LPAR Info: 48 l0790p046
Memory Size: 4096 MB
Good Memory Size: 4096 MB
Platform Firmware level: VL910_059
Firmware Version: IBM,FW910.00 (VL910_059)
Console Login: enable
Auto Restart: true
Full Core: false
NX Crypto Acceleration: Capable and Enabled
…
So, there you have it. Once you install 7200-03-01 in an LPAR running on POWER9 (only), and reboot, the SMT mode will change to 8. Just as advertised!
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