Re: [PATCH v7 0/4] Add support for parametrized events

On Wed, Jan 07, 2015 at 05:13:49PM -0800, Sukadev Bhattiprolu wrote:

Description of "event parameters" from the documentation patch:

    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.

Description of the sysfs contents when events are parameterized (copied from an
included patch):

	Examples:

		domain=0x1,offset=0x8,core=?

	In the case of the last example, a value replacing "?" would need
	to be provided by the user selecting the particular event. This is
	refered to as "event parameterization". All non-numerical values
	indicate an event parameter.

Notes on how perf-list displays parameterized events

	PARAMETERIZED EVENTS
	--------------------

	Some pmu events listed by 'perf list' will be displayed with '$xyz' in
	them. For example:

	  hv_24x7/HPM_THREAD_NAP_CCYC__PHYS_CORE,core=?/

	This means that when provided as an event, a value for ? must also
	be supplied. For example:

	  perf stat  -e \
	  	'hv_24x7/HPM_THREAD_NAP_CCYC__PHYS_CORE,core=2' ...

Changelog[v7]
	[Jiri Olsa] Nit: Add braces for clarity.
	[Jiri Olsa] Add a check to make sure that sysfs entries have with
	parameters exactly match '=?'.

for the patchset:

Acked-by: Jiri Olsa <jolsa@kernel.org>

thanks,
jirka