Make it explicit that the format attributes may define overlapping bit ranges. Unfortunately this was left unspecified originally, and all the examples show non-overlapping ranges. I don't believe this is an ABI change, as we are defining something that was previously undefined, but others may disagree. The POWER8 PMU would like to define overlapping ranges, as bit ranges in the event code have different meanings for certain events. It will also allow us to define an overarching "event" field, that encompasses all others. As far as I can see perf is comfortable with this change, however I am not sure if there are any other users of the interface. Signed-off-by: Michael Ellerman <michael@xxxxxxxxxxxxxx> --- Documentation/ABI/testing/sysfs-bus-event_source-devices-format | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-bus-event_source-devices-format b/Documentation/ABI/testing/sysfs-bus-event_source-devices-format index 079afc7..77f47ff 100644 --- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-format +++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-format @@ -9,6 +9,12 @@ Description: we want to export, so that userspace can deal with sane name/value pairs. + Userspace must be prepared for the possibility that attributes + define overlapping bit ranges. For example: + attr1 = 'config:0-23' + attr2 = 'config:0-7' + attr3 = 'config:12-35' + Example: 'config1:1,6-10,44' Defines contents of attribute that occupies bits 1,6-10,44 of perf_event_attr::config1. -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
