Hello SJ, On Mon, Aug 17, 2026 at 12:56 AM SJ Park <[email protected]> wrote: > > Hello Kunwu, > > On Sun, 16 Aug 2026 22:22:17 +0800 Kunwu Chan <[email protected]> wrote: > > > From: Kunwu Chan <[email protected]> > > > > This series adds an AUX trace-buffer backend to the DAMON perf > > observability framework, enabling ARM SPE (Statistical Profiling > > Extension) to deliver hardware-sampled access reports into DAMON's > > existing SPSC report ring. > > Awesome. Thank you for making this. This will make DAMON be more useful on > ARM machines.
Thanks for the feedback. > > > > > Patch 2 touches drivers/perf/arm_spe_pmu.c to expose the PMU matcher. > > This change is tightly coupled with the DAMON AUX backend. ARM SPE > > PMU driver maintainers only need to review patch 2. > > > > This series is based on the Ravi's hardware-sampled access reports > > branch [1], and depends on the perf AUX kernel-consumer RFC series [2]. > > The dependencies is not upstream yet, so this series remains RFC. > > Unfortunately I haven't had a time to thoroughly read the dependent patches. > I > believe the basic idea of this patch series is aligned with the ongoing DAMON > extension roadmap [1], though. That is, this series is supposed to be a part > of the milestone 3. We are currently at the near end of milestone 1, and aim > to complete milestone 2 by the time around next year's LSFMMBPF. One clarification on the architecture: the AUX backend is intended as a transport/front-end for damon_report_access(), rather than a separate reporting path. spe_submit() ultimately calls damon_report_access(&report), and the AUX path shares the same SPSC report ring and kdamond_check_reported_accesses() consumer with the existing overflow-callback path. The main difference is the producer context: the overflow path enqueues from NMI context, while the AUX path enqueues from kdamond process context. The perf AUX kernel-consumer API is still an upstream dependency, so there is no specific part that needs your review right now. The implementation is already functional and tested on Kunpeng 920, and I can rebase and resend once the dependency chain is ready and the relevant DAMON infrastructure has landed. Separately, the DAMON perf observability framework (CONFIG_DAMON_PERF_OBSERVE) was developed in parallel with the AUX backend and is already implemented. It provides the observability infrastructure used by both the existing overflow path and the new AUX path, including per-CPU pipeline counters, debugfs statistics, and tracepoints. This work is independent of the AUX transport, and I will post it shortly as a standalone series. Thanks, Kunwu > > I will hold review of this series for now, and take more time on making > milestones 1 and 2 for thier planned delivery timeline. Sorry for being a > bottleneck of your work, and thanks in advance for your patience. > > Please feel free to let me know if you have specific parts that need my review > right now, though. Otherwise, please make sure this is aligned with the > roadmap until we finish the milestone 2. I do want ARM SPE support of DAMON. > > [1] https://lore.kernel.org/all/[email protected]/ > > > Thanks, > SJ > > [...]
