60x speed-up of Linux “perf” (eighty-twenty.org)

Article summary

The Linux "perf" tool has a performance issue due to its use of addr2line, which can be resolved by patching perf to use a long-running addr2line process. This patch results in a 60x speed-up. The issue is caused by perf being licensed under GPLv2, which is incompatible with the GPLv3 license of the libbfd library it needs to use. The author of the patch discusses the licensing issue and its implications.

Main themes

• GPL licensing issues
• Linux kernel licensing
• Software compatibility
• Open-source licensing
• License incompatibility
• GPLv2 vs GPLv3

What commenters say

• The GPL license can cause problems due to its incompatibility with itself and other licenses.
• The lack of an 'or later' clause in the Linux kernel's GPLv2 license is the root cause of the issue.
• The GPL license is not the problem, but rather the authors' decision to license their work in a certain way.
• The 'or later' clause is a necessary provision to ensure compatibility with future versions of the GPL.
• The GPL license can limit the use of improved or more performant code due to its restrictions.
• The issue is not with the GPL license itself, but with the cultural standards surrounding it.
• The problem can be fixed with a license change, but this is often impossible for large projects due to the need for consensus among all contributors.
• The GPL license does not require giving code back, and its restrictions are often misunderstood.