On Mon, Jan 23, 2023 at 5:26 AM John Garry [off-list ref] wrote:

On 21/12/2022 22:34, Ian Rogers wrote:

quoted

Add an optimization to jevents using the metric code, rewrite metrics
in terms of each other in order to minimize size and improve
readability. For example, on Power8
other_stall_cpi is rewritten from:
"PM_CMPLU_STALL / PM_RUN_INST_CMPL - PM_CMPLU_STALL_BRU_CRU / PM_RUN_INST_CMPL - PM_CMPLU_STALL_FXU / PM_RUN_INST_CMPL - PM_CMPLU_STALL_VSU / PM_RUN_INST_CMPL - PM_CMPLU_STALL_LSU / PM_RUN_INST_CMPL - PM_CMPLU_STALL_NTCG_FLUSH / PM_RUN_INST_CMPL - PM_CMPLU_STALL_NO_NTF / PM_RUN_INST_CMPL"
to:
"stall_cpi - bru_cru_stall_cpi - fxu_stall_cpi - vsu_stall_cpi - lsu_stall_cpi - ntcg_flush_cpi - no_ntf_stall_cpi"
Which more closely matches the definition on Power9.

A limitation of the substitutions are that they depend on strict
equality and the shape of the tree. This means that for "a + b + c"
then a substitution of "a + b" will succeed while "b + c" will fail
(the LHS for "+ c" is "a + b" not just "b").

Separate out the events and metrics in the pmu-events tables saving
14.8% in the table size while making it that metrics no longer need to
iterate over all events and vice versa. These changes remove evsel's
direct metric support as the pmu_event no longer has a metric to
populate it. This is a minor issue as the code wasn't working
properly, metrics for this are rare and can still be properly ran
using '-M'.

Add an ability to just build certain models into the jevents generated
pmu-metrics.c code. This functionality is appropriate for operating
systems like ChromeOS, that aim to minimize binary size and know all
the target CPU models.

 From a glance, this does not look like it would work for arm64. As I
see in the code, we check the model in the arch folder for the test to
see if built. For arm64, as it uses arch/implementator/model folder org,
and not just arch/model (like x86)

So on the assumption that it does not work for arm64 (or just any arch
which uses arch/implementator/model folder org), it would be nice to
have that feature also. Or maybe also support not just specifying model
but also implementator.

Hmm.. this is tricky as x86 isn't following the implementor pattern. I
will tweak the comment for the ARM64 case where --model will select an
implementor.

quoted

v2. Rebase. Modify the code that skips rewriting a metric with the
     same name with itself, to make the name check case insensitive.

Unfortunately you might need another rebase as this does not apply to
acme perf/core (if that is what you want), now for me at:

5670ebf54bd2 (HEAD, origin/tmp.perf/core, origin/perf/core, perf/core)
perf cs-etm: Ensure that Coresight timestamps don't go backwards

Will do, thanks!
Ian

quoted

Ian Rogers (9):
   perf jevents metric: Correct Function equality
   perf jevents metric: Add ability to rewrite metrics in terms of others
   perf jevents: Rewrite metrics in the same file with each other
   perf pmu-events: Separate metric out of pmu_event
   perf stat: Remove evsel metric_name/expr
   perf jevents: Combine table prefix and suffix writing
   perf pmu-events: Introduce pmu_metrics_table
   perf jevents: Generate metrics and events as separate tables
   perf jevents: Add model list option

Thanks,
John