saptune 3.2.3 – Enhancements, Fixes and Updates (Azure Users, Please Read This!)

If a package line in a [rpm] section is prefixed with a ?, the requirement will only be checked if the package is installed.
Lets see an example:

[rpm]
glibc 2.31-150300.46.1
?sssd 2.9.3-150600.3.25.1

The glibc` package must be present in at least version 2.31-150300.46.1, but the sssd package has to be at least version 2.9.3-150600.3.25.1. if installed at all.
The man page saptune-note(5) explains it in more detail.

The TSX setting is bound to specific kernel versions, so we introduce a new tag kernel=REGEX available for every section. If used, the section applies only for kernel versions (uname -r) matching the regular expression.
Here an example from the shipped SAP Note:

[grub:os=15-SP6:arch=x86_64:kernel=^6\.4\.0-150600\.23\.(42|47|50|53|60)-default$]
tsx=auto

The man page saptune-note(5) explains it in more detail.

The force_latency parameter supports now c-state names as well. Internally the c-state gets translated into its latency value for the current CPU. From that on, the parameter works as before: All states with a higher latency value get disabled. If the state does not exist, the tuning gets ignored.

Here an example from the SAP Note:

[cpu:csp=aws]
force_latency=C1

The man page saptune-note(5) explains it in more detail.

With starting to support the HotFix idea in 3.2.2, naming collisions between shipped and Custom Notes might occur more often. A shipped HotFix Note can have the same name as an earlier created Custom Note.

This is not a bad thing, but intended! TIDs can recommend to create a Custom Note for a workaround with the same name of the Note saptune will ship in the next version. The Custom Note will mitigate the problem immediately and if the saptune version containing the HotFix gets installed, the shipped Note will take precedence over the Custom Note. This allows to “replace” the custom Note with additional workarounds or conditions to apply them only when needed. The Custom Note can then removed later.

In case a Custom Note or Custom Solution has the same name as a shipped one, this will result:

• in a warning printed whenever saptune gets executed,
• an entry in /var/log/saptune/saptune.log,
• a ! in the respective line in the output of saptune note list or saptune solution list, which is also colored if coloring has not been disabled and
• the Custom Note will not have any effect anymore.

A few weeks ago, we released 3.2.2 as A HotFix update to address a critical issue (saptune 3.2.2 – THP HotFix). Now a kernel fix is available, so we limit the mitigation only to those kernels affected by the problem. If you have a Custom Note
HotFix000022286 the shipped version in 3.2.3 will take over (see also “Warning about Duplicate Notes” above).

Two bugs get fixed with 3.2.3 as well.
The first has been hiding for quite some time, but a customer spotted it. On revert the entire state of units listed in the [service] section has been restored and not only the configured part. The second one we found ourselves. A saptune verify applied returned an incorrect text when Notes have been enabled,
but not applied. That has been fixed.

With 3.2.3 we deprecated SAP Note 941735 to remove it in 3.3. We talked to SAP and the Note is only needed in some very old setups. The TMPFS part of the Note caused problems now and then, but seems to have no real use anymore- If you run a scenario where the TMPFS setting is a must, please let us know.

This is summary:

• SAP Note 2684254 updated to Version 27: check that TSX is set to auto on systems running dedicated kernel releases
• SAP Note 1656250 updated to Version 71: disable C-states higher than C1
• SAP Note 2578899 updated to Version 55: check for optional sssd package version
• SAP Note 1275776 updated to Version 47: no tuning changes