![Michael Ellerman](/assets/img/avatar_default.png)
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@ellerman.id.au> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/1368199980-20283-1-git-send-email-jolsa@redhat.com Signed-off-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
21 lines
704 B
Plaintext
21 lines
704 B
Plaintext
Where: /sys/bus/event_source/devices/<dev>/format
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Date: January 2012
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Kernel Version: 3.3
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Contact: Jiri Olsa <jolsa@redhat.com>
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Description:
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Attribute group to describe the magic bits that go into
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perf_event_attr::config[012] for a particular pmu.
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Each attribute of this group defines the 'hardware' bitmask
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we want to export, so that userspace can deal with sane
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name/value pairs.
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Userspace must be prepared for the possibility that attributes
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define overlapping bit ranges. For example:
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attr1 = 'config:0-23'
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attr2 = 'config:0-7'
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attr3 = 'config:12-35'
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Example: 'config1:1,6-10,44'
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Defines contents of attribute that occupies bits 1,6-10,44 of
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perf_event_attr::config1.
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