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    SubjectRe: [rfc] Describe events in a structured way via sysfs
    On 20.07.10 01:48:28, Lin Ming wrote:
    The caller reads config and type and pass them into perf_event_attr.
    >
    > 1. Hardware events
    > /sys/devices/system/cpu/cpu0...cpuN/events
    > |-- L1-dcache-load-misses ===> event name
    > | |-- config ===> config value for the event
    > | `-- type ===> event type

    Wouldn't it be much easier to have a unique sysfs id (could be an
    u64):

    > |-- L1-dcache-load-misses ===> event name
    > | `-- id ===> event id

    ... and then extend the syscall to enable an event by its sysfs id:

    memset(&attr, 0, sizeof(attr));
    attr.type = PERF_TYPE_SYSFS;
    attr.sysfs_id = sysfs_id;
    attr.sample_type = PERF_SAMPLE_CPU | PERF_SAMPLE_RAW;
    attr.config = config;
    ...

    The kerrnel then knows which event is meant and the don't have to
    provide event specific paramaters such as type/config that requires an
    event specific setup. The advantage would be that we can open an event
    file descriptor of every kind of event in a standardized way.

    -Robert

    --
    Advanced Micro Devices, Inc.
    Operating System Research Center



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