** Description changed: [impact] glibc 2.32 contained a number of improvements to the memcpy routines for server-grade AArch64 implementations (in particular, graviton2 & graviton3). They should be backported to focal, as the LTS releases are by far the most used on servers. [test case] Compile the test_memcpy.c that is attached to bug 1928508: $ gcc -g -O3 test_memcpy.c -o test_memcpy64 - This should be run before and after installing the libc packages from - proposed. On graviton2 systems, this should show a substantial - improvement. On other arm64 systems (raspberry pis of various vintage, - thunderx2, xgene, etc etc) at least no significant regression should be - seen. + "./test_memcpy64 32" should be run before and after installing the libc + packages from proposed. On graviton2 systems, this should show a + substantial improvement. On other arm64 systems (raspberry pis of + various vintage, thunderx2, xgene, etc etc) at least no significant + regression should be seen. [regression potential] Rebuilding glibc is always a little risky (toolchain bugs and incompatibilities between the old and new versions can be surprising). But the autopkgtests and some manual general testing can help here. For this specific change, there is a potential risk that the new memcpy implementation could be used on a system where it is not in fact the fastest. We should run the test case not only on the systems where it is expected to help, but other systems such as the RPi4 and the launchpad build farm to ensure performance is not regressed there.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1951032 Title: AArch64: Backport memcpy improvements To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/glibc/+bug/1951032/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
