Messages in this thread | | | Subject | Re: [PATCH 2/7] perf: Create a symlink for a PMU | From | "Liang, Kan" <> | Date | Fri, 25 Jun 2021 12:18:28 -0400 |
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On 6/25/2021 11:57 AM, Liang, Kan wrote: > > > On 6/25/2021 11:44 AM, Andi Kleen wrote: >> >>> We have an attribute "caps/pmu_name" for the core PMU. Maybe we >>> should add it for uncore PMU as well. For example, >>> >>> $ cat /sys/devices/uncore_type_0_0/caps/pmu_name >>> cha_0 >>> >>> Userspace tool can get clues about what type_0_0 is. >> >> It would break all the old tools, but I suppose it could work for >> updated tools. >> > > Right, users have to update their perf tool to use the new name, > uncore_cha_0.
I think the above example is misleading. Let me rephrase. Here is what I'm planing to do in V2.
With the V2 platform-specific patch, uncore driver will only create a meaningful uncore name, e.g., uncore_cha_0.
An attribute "caps/pmu_name" is also created to indicate the previous name. For example,
$ cat /sys/devices/uncore_cha_0/caps/pmu_name type_0_0
If any users use the old numeric name, they have to update either their script or a perf tool which supports "caps/pmu_name".
In the future, if the users already use a perf tool which supports "caps/pmu_name", nothing needs to be updated. The old numeric name should just work.
Thanks, Kan
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