Messages in this thread | | | From | Rob Herring <> | Date | Tue, 8 Nov 2022 07:12:53 -0600 | Subject | Re: [PATCH v3 8/8] perf: arm_spe: Add support for SPEv1.2 inverted event filtering |
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On Mon, Nov 7, 2022 at 1:48 PM Namhyung Kim <namhyung@kernel.org> wrote: > > Hello, > > On Fri, Nov 4, 2022 at 8:55 AM Rob Herring <robh@kernel.org> wrote: > > > > Arm SPEv1.2 (Arm v8.7/v9.2) adds a new feature called Inverted Event > > Filter which excludes samples matching the event filter. The feature > > mirrors the existing event filter in PMSEVFR_EL1 adding a new register, > > PMSNEVFR_EL1, which has the same event bit assignments. > > Just out of curiosity, is it possible to have the event filter and > inverted filter at the same time?
Yes, that's why config3 is needed. Samples with all the events set in PMSEVFR_EL1 and none of the events set in PMSNEVFR_EL1 are recorded. For example if an event bit is 0 in PMSEVFR_EL1, then recorded samples may or may not have that event. If the same event bit is then set in PMSNEVFR_EL1, then record samples will not have that event.
> What if they have the same?
You'd get no samples.
Rob
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