On Thu, Feb 03, 2022 at 03:28:41PM +0530, Ravi Bangoria wrote: > Perf counter may overcount for a list of Retire Based Events. Implement > workaround for Zen3 Family 19 Model 00-0F processors as suggested in > Revision Guide[1]: > > To count the non-FP affected PMC events correctly: > o Use Core::X86::Msr::PERF_CTL2 to count the events, and > o Program Core::X86::Msr::PERF_CTL2[43] to 1b, and > o Program Core::X86::Msr::PERF_CTL2[20] to 0b. > > Note that the specified workaround applies only to counting events and > not to sampling events. Thus sampling event will continue functioning > as is. > > Although the issue exists on all previous Zen revisions, the workaround > is different and thus not included in this patch. > > This patch needs Like's patch[2] to make it work on kvm guest. > > [1] https://bugzilla.kernel.org/attachment.cgi?id=298241 > [2] https://lore.kernel.org/lkml/20220117055703.52020-1-likexu@xxxxxxxxxxx > > Signed-off-by: Ravi Bangoria <ravi.bangoria@xxxxxxx> Thanks!
