Hi, On 13.05.2024 12:45, Tvrtko Ursulin wrote: > > On 13/05/2024 11:22, Jacek Lawrynowicz wrote: >> Hi, >> >> On 10.05.2024 18:55, Jeffrey Hugo wrote: >>> On 5/8/2024 7:29 AM, Jacek Lawrynowicz wrote: >>>> From: Tomasz Rusinowicz <tomasz.rusinowicz@xxxxxxxxx> >>>> >>>> The driver tracks the time spent by NPU executing jobs >>>> and shares it through sysfs `npu_busy_time_us` file. >>>> It can be then used by user space applications to monitor device >>>> utilization. >>>> >>>> NPU is considered 'busy' starting with a first job submitted >>>> to firmware and ending when there is no more jobs pending/executing. >>>> >>>> Signed-off-by: Tomasz Rusinowicz <tomasz.rusinowicz@xxxxxxxxx> >>>> Signed-off-by: Jacek Lawrynowicz <jacek.lawrynowicz@xxxxxxxxxxxxxxx> >>> >>> This feels like something that would normally be handled by perf. Why not use that mechanism? >> >> Yeah, probably but we had several request to provide easy to use interface for this metric that >> could be integrated in various user space apps/tools that do not use ftrace. > > Probably more Perf/PMU aka performance counters? Which would be scriptable via $kernel/tools/perf or directly via perf_event_open(2) and read(2). > > Note it is not easy to get right and in the i915 implementation (see i915_pmu.c) we have a known issue with PCI hot unplug and use after free which needs input from perf core folks. OK, we will consider using perf/pmu for NPU but for the moment I would like to keep this sysfs interface. It so simple it can be used from bash and it always can be removed if obsoleted by something fancier.
