Public bug reported: A patch has recently landed upstream to optimize memcmp for AArch64:
commit 922369032c604b4dcfd535e1bcddd4687e7126a5 Author: Wilco Dijkstra <[email protected]> Date: Thu Aug 10 17:00:38 2017 +0100 [AArch64] Optimized memcmp. This is an optimized memcmp for AArch64. This is a complete rewrite using a different algorithm. The previous version split into cases where both inputs were aligned, the inputs were mutually aligned and unaligned using a byte loop. The new version combines all these cases, while small inputs of less than 8 bytes are handled separately. This allows the main code to be sped up using unaligned loads since there are now at least 8 bytes to be compared. After the first 8 bytes, align the first input. This ensures each iteration does at most one unaligned access and mutually aligned inputs behave as aligned. After the main loop, process the last 8 bytes using unaligned accesses. This improves performance of (mutually) aligned cases by 25% and unaligned by >500% (yes >6 times faster) on large inputs. * sysdeps/aarch64/memcmp.S (memcmp): Rewrite of optimized memcmp. ** Affects: glibc (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1720832 Title: Optimized memcmp for arm64 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/glibc/+bug/1720832/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
