Merged as part of the perf subsystem fixes overnight is enabling Auto Counter Reload (ACR) functionality for upcoming Intel Xeon Diamond Rapids processors. This ACR enabling for Diamond Rapids "DMR" is happening in time for Linux 7.1-rc3 on Sunday while the work is also marked for back-porting to existing stable kernels.

Auto Counter Reload is a new low-overhead, performance monitoring capability for automatically reloading of performance counters when specific event conditions occur. Auto Count(er) Reload is initially present on [1]Clearwater Forest CPUs and also coming for Diamond Rapids.

The Linux kernel needs a one-liner patch for enabling Auto Counter Reload on Diamond Rapids due to a special condition leading it to not being enabled otherwise with the existing ACR kernel code.

[2]This merge to Linux 7.1 Git enables ACR on Diamond Rapids. As mentioned, it will also be back-ported to supported stable Linux kernel versions in the near future.



[1] https://www.phoronix.com/news/Linux-6.16-Performance-Events

[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e5cf0260a7472b4f34a46c418c14bec272aac404