On Fri, Oct 16, 2020 at 10:36 AM Rafael J. Wysocki <raf...@kernel.org> wrote: > > On Fri, Oct 16, 2020 at 7:18 PM Wei Wang <w...@google.com> wrote: > > > > On Fri, Oct 16, 2020 at 10:01 AM Rafael J. Wysocki <raf...@kernel.org> > > wrote: > > > > > > On Fri, Oct 16, 2020 at 6:36 PM Wei Wang <w...@google.com> wrote: > > > > > > > > Currently, raw cache will be reset when next_f is changed after > > > > get_next_freq for correctness. However, it may introduce more > > > > cycles. This patch changes it to maintain the cached value instead of > > > > dropping it. > > > > > > IMV you need to be more specific about why this helps. > > > > > > > I think the idea of cached_raw_freq is to reduce the chance of calling > > cpufreq drivers (in some arch those may be costly) but sometimes the > > cache will be wiped for correctness. The purpose of this patch is to > > still keep the cached value instead of wiping them. > > Well, I see what the problem is and how the patch is attempting to > address it (which is not the best way to do that because of the extra > struct member that doesn't need to be added if I'm not mistaken), but > IMO the changelog is way too vague from the problem statement > perspective.
Just want to bring this up in the mainline kernel. I think we can change the patch to use a variable insides sugov_update_single. This is adapted from Android common kernel where it has some off tree functions making a single variable not possible but also making the issue more obvious.