4 ms·

Timestamps should NOT be compared like this. Exactly this is why time_before() or time_after() exist. https://elixir.bootlin.com/linux/v6.15.7/source/include/l

• Joker_vD 9mo ago
  Do I understand it correctly that the logic is that if timestamp B is above timestamp A, but the difference is more than half of the unsigned range, B is considered to happen before A?
  • rcxdude 9mo ago
    Yes. When the timestamps wrap it's fundamentally ambiguous, but this will be correct unless the timestamps are very far apart (and the failure mode is more benign: a really long time difference being considered shorter is better than all time differences being considered zero after the timestamp wraps).
• AceJohnny2 9mo ago
  Offtopic... * Do this with "<0" and ">=0" to only test the sign of the result. A * good compiler would generate better code (and a really good compiler * wouldn't care). Gcc is currently neither. It's funny the love-hate relationship the Linux kernel has with GCC. It's the only supported compiler[1], and yet... [1] can Clang fully compile Linux yet? I haven't followed the updates in a while.
  • EvgeniyZh 9mo ago
    Yes it can [1]. https://docs.kernel.org/kbuild/llvm.html https://docs.kernel.org/kbuild/llvm.html
  • rwmj 9mo ago
    To be fair this comment predates git history (before 2005) when GCC wasn't a very good compiler. The kernel developers at one point were sticking with a specific version of GCC because later versions would miscompile the kernel. Clang didn't exist then. GCC is a different beast and far better nowadays.