Changes/z13BaselineForIBMZ

z13 as the Baseline for IBM Z Hardware

Summary

we want to move the minimal architecture level for IBM Z hardware (the s390x architecture) to z13 to benefit from the new features. The current minimum at zEC12 is targeting hardware that has been already obsoleted by the vendor. All Fedora infrastructure is already using the latest z15 hardware (builders and co and also our public resources for developers). But we still want to be able to use existing z13 and z14 hardware.

Owner

• Name: Dan Horák
• Email: <sharkcz@fedoraproject.org>

Current status

• Targeted release: Fedora Linux 36
• Last updated: 2022-01-12
• FESCo issue: <will be assigned by the Wrangler>
• Tracker bug: <will be assigned by the Wrangler>
• Release notes tracker: <will be assigned by the Wrangler>

Benefit to Fedora

The primary benefit is being able to exploit vector instructions by default, which should increase performance.

Scope

• Proposal owners:
  • update the minimal hardware level in the kernel config
  • set default compiler flags to -mcpu=z13 -mtune=z14 in redhat-rpm-config and gcc

• Other developers:

none

• Release engineering: #Releng issue number

• Policies and guidelines: N/A (not needed for this Change)

• Trademark approval: N/A (not needed for this Change)

• Alignment with Objectives:

Upgrade/compatibility impact

Users with hardware older than z13 should stick with F35 or older release.

How To Test

You shouldn't be able to start Fedora Linux 36 on system older than z13.

User Experience

The primary difference will be in the availability of the vector instructions and as a result better performance.

Contingency Plan

• Contingency mechanism: (What to do? Who will do it?) N/A (not a System Wide Change)
• Contingency deadline: N/A (not a System Wide Change)
• Blocks release? N/A (not a System Wide Change), Yes/No

Documentation

N/A (not a System Wide Change)

Release Notes

Starting with Fedora Linux 36 the minimal hardware level for the s390x architecture has been updated to z13.