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 '$xyz' in
them. For example:
hv_24x7/HPM_THREAD_NAP_CCYC__PHYS_CORE,core=?/
This means that when provided as an event, a value for ? must also
be supplied. For example:
perf stat -e \
'hv_24x7/HPM_THREAD_NAP_CCYC__PHYS_CORE,core=2' ...
Changelog[v6]
[Jiri Olsa, Sukadev Bhattiprolu] Rather than display
'starting_index=$core' in perf.list and sysfs and expect user to
specify a value for 'starting_index', replace 'starting_index' with
what it really means for the event. i.e for an event, if starting_index
refers to 'core' then display 'core=?' in both perf list and sysfs (see
examples above).
Changelog[v5]
- [Jiri Olsa, Peter Zijlstra] Use '$arg' notation rather than ?
to indicate event parameters.
- [Michael Ellerman] Separate the kernel and tool patches in the
patchset into different patchsets.
Changelog[v4]
- [Jiri Olsa] Rebase to perf/core tree (fix small merge conflict)
Changelog[v3]
- [Jiri Olsa] Changed the event parameters are specified. If
event file specifes 'param=val' make the usage 'param=123'
rather than 'val=123'. (patch 1,2/10)
- Shortened event names using "PHYS" and "VCPU" (patch 4/10)
- Print help message if invalid parameter is specified or required
parameter is missing.
- Moved 3 patches that are unrelated to parametrized events into
a separate patchset.
- Reordered patches so code changes come first.
Changelog[v2]
- [Joe Perches, David Laight] Use beNN_to_cpu() instead of guessing
the size from type.
- Use kmem_cache_free() to free page allocated with kmem_cache_alloc().
- Rebase to recent kernel
Cody P Schafer (4):
tools/perf: support parsing parameterized events
tools/perf: extend format_alias() to include event parameters
perf Documentation: add event parameters
tools/perf: Document parameterized and symbolic events
.../testing/sysfs-bus-event_source-devices-events | 6 ++
tools/perf/Documentation/perf-list.txt | 13 +++
tools/perf/Documentation/perf-record.txt | 12 +++
tools/perf/Documentation/perf-stat.txt | 20 ++++-
tools/perf/util/parse-events.h | 1 +
tools/perf/util/pmu.c | 92 +++++++++++++++++++---
6 files changed, 128 insertions(+), 16 deletions(-)
--
1.8.3.1
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