Thread (30 messages) 30 messages, 4 authors, 2023-02-04

Re: [PATCH v5 00/15] jevents/pmu-events improvements

From: John Garry <john.g.garry@oracle.com>
Date: 2023-01-27 13:21:41
Also in: linux-arm-kernel, linux-perf-users, lkml

On 26/01/2023 23:36, Ian Rogers wrote:

Hi Ian,

At a glance, none of this series has your Signed-off-by tag..

Thanks,
John
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.
  
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help