Messages in this thread | | | Subject | Re: [PATCH RFC 0/7] perf pmu-events: Support event aliasing for system PMUs | From | John Garry <> | Date | Wed, 19 Feb 2020 14:28:10 +0000 |
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>>> i.MX8MM and i.MX8MN, they use the same driver(DDRC_ID) and cortex-a53 >> integrated. >>> >>> If we want to monitor VPU, their *master id* is different from SoCs. >>> On i.MX8MM, event is imx8_ddr0/axid-read,axi_id=0x08/ On i.MX8MN, >>> event is imx8_ddr0/axid-read,axi_id=0x12/ >>>
So it seems that this master id and the axi_id are the same, which is some filtering key. Indeed, the actual event number is the same between SoC implementations.
And metric groups do support filtering, AFAIU.
>>> I try to write a JSON file to use these events, for now, I only can >>> locate the file at the directory: >>> tools/perf/pmu-events/arch/arm64/arm/cortex-a53/ >>> >>> Perf tool loads all events when CPUID matched, which is now unreasonable, >> we want related events are loaded for specific SoC. >> >> so we could have a folder like .../arch/arm64/nxp/system for these JSONs. The >> perf tool can be updated to handle CPU and system events in separate folders. >> >>> >>> All events will also be loaded if we use DDRC_ID to match in the future, this >> seems to not be a good ideal. >> >> The important part is knowing which events are supported per implementation. >> Is there any method in the driver of knowing the specific implementation, like >> any DT compat string? Least preferred option would be DT machine ID. > > I think, NO, master id could be different even they use the same DT compatible string.
Are you sure? Checking the dts files for your SoCs, I see this:
~/kernel-dev6/arch/arm64$ git grep "fsl,imx8m-ddr-pmu" boot/dts/freescale/imx8mm.dtsi: compatible = "fsl,imx8mm-ddr-pmu", "fsl,imx8m-ddr-pmu"; boot/dts/freescale/imx8mn.dtsi: compatible = "fsl,imx8mn-ddr-pmu", "fsl,imx8m-ddr-pmu"; boot/dts/freescale/imx8mq.dtsi: compatible = "fsl,imx8mq-ddr-pmu", "fsl,imx8m-ddr-pmu";
So it seems that you could use "fsl,imx8mm-ddr-pmu" vs "fsl,imx8mn-ddr-pmu" to differentiate, right?
John
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