The memory event can deliver two benefits:
- The first benefit is the memory event can give out global view for
memory accessing, rather than organizing events with scatter mode
(e.g. uses separate event for L1 cache, last level cache, etc) which
which can only display a event for single memory type, memory events
include all memory accessing so it can display the data accessing
cross memory levels in the same view;
- The second benefit is the sample generation might introduce a big
overhead and need to wait for long time for Perf reporting, we can
specify itrace option '--itrace=M' to filter out other events and only
output memory events, this can significantly reduce the overhead
caused by generating samples.
This patch is to enable memory event for Arm SPE.
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: James Clark <james.clark@arm.com>
Tested-by: James Clark <james.clark@arm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Al Grant <al.grant@arm.com>
Cc: Andre Przywara <andre.przywara@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wei Li <liwei391@huawei.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20210211133856.2137-5-james.clark@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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