perf Documentation: Add event parameters
Event parameters are a basic way for partial events to be specified in sysfs with per-event names given to the fields that need to be filled in when using a particular event. It is intended for supporting cases where the single 'cpu' parameter is insufficient. For example, POWER 8 has events for physical sockets/cores/cpus that are accessible from with virtual machines. To keep using the single 'cpu' parameter we'd need to perform a mapping between Linux's cpus and the physical machine's cpus (in this case Linux is running under a hypervisor). This isn't possible because bindings between our cpus and physical cpus may not be fixed, and we probably won't have a "cpu" on each physical cpu. Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com> Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Cody P Schafer <dev@codyps.com> Cc: Haren Myneni <hbabu@us.ibm.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/1420679633-28856-4-git-send-email-sukadev@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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@ -52,12 +52,18 @@ Description: Per-pmu performance monitoring events specific to the running syste
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event=0x2abc
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event=0x423,inv,cmask=0x3
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domain=0x1,offset=0x8,starting_index=0xffff
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domain=0x1,offset=0x8,core=?
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Each of the assignments indicates a value to be assigned to a
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particular set of bits (as defined by the format file
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corresponding to the <term>) in the perf_event structure passed
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to the perf_open syscall.
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In the case of the last example, a value replacing "?" would
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need to be provided by the user selecting the particular event.
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This is referred to as "event parameterization". Event
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parameters have the format 'param=?'.
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What: /sys/bus/event_source/devices/<pmu>/events/<event>.unit
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Date: 2014/02/24
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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