It's been some time since the original benchmarks, so I'm repeating the test from the description. I haven't used hyperfine for the comparisons below, so they won't have the same statistical reliability but should nevertheless be sufficient for validation.
Binaries have been compiled as below: $ gcc -mtune=generic -march=x86-64 -g -O3 test_memcpy.c -o test_memcpy64 ---- AMD ---- $ grep -m1 "model name" /proc/cpuinfo model name : AMD Ryzen 7 3700X 8-Core Processor $ dpkg -l | grep -m1 libc6 ii libc6:amd64 2.31-0ubuntu9.2 amd64 GNU C Library: Shared libraries $ ./test_memcpy64 32 32 MB = 2.506206 ms -Compare match (should be zero): 0 $ dpkg -l | grep -m1 libc6 ii libc6:amd64 2.31-0ubuntu9.4~20210524ppa1 amd64 GNU C Library: Shared libraries $ ./test_memcpy64 32 32 MB = 1.384115 ms -Compare match (should be zero): 0 So, for AMD it's a very noticeable improvement (1.38ms vs 2.51ms). ---- Intel ---- $ grep -m1 "model name" /proc/cpuinfo model name : Intel(R) Xeon(R) CPU E5-2683 v3 @ 2.00GHz $ dpkg -l | grep -m1 libc6 ii libc6:amd64 2.31-0ubuntu9.2 amd64 GNU C Library: Shared libraries $ ./test_memcpy64 32 32 MB = 2.304554 ms -Compare match (should be zero): 0 $ dpkg -l | grep -m1 libc6 ii libc6:amd64 2.31-0ubuntu9.4~20210524ppa1 amd64 GNU C Library: Shared libraries $ ./test_memcpy64 32 32 MB = 2.209747 ms -Compare match (should be zero): 0 For Intel the difference isn't very significant, but there are also no performance regressions (2.30ms vs 2.21ms). -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1928508 Title: Performance regression on memcpy() calls for AMD Zen To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/glibc/+bug/1928508/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
