This series replaces the cpu_frequency trace event with a new trace event,
policy_frequency. Since by definition all CPUs in a policy are of the same
frequency, we can emit a frequency change per policy instead of per CPU.
This saves some compute and memory from the kernel side, while simplifying
analysis from the post-processing of the trace log side.
Any process that relied on cpu_frequency trace event needs to switch to the
new policy_frequency trace event in order to maintain functionality. The
decision of replacing instead of adding the trace event is intentional. Since
emitting once per policy instead of once per CPU is anyways a semantics change
that would require a tooling update, the trace event was also appropriately
renamed. The presence of the policy_frequency event in a trace log is a clear
and obvious signal for tooling to determine kernel version and which trace
event to parse.
1/2: Replaces trace_cpu_frequency with trace_policy_frequency
2/2: Corresponding documentation patch that updates references to
cpu_frequency with policy_frequency
Changes in v3:
- Resending v2 properly (accidentally ommited cover letter in v2)
Changes in v2:
- Replaced trace_cpu_frequency with trace_policy_frequency (per Christian
and Viresh)
- Updated references to cpu_frequency in documentation with
policy_frequency
- v1 link:
https://lore.kernel.org/all/[email protected]
Samuel Wu (2):
cpufreq: Replace trace_cpu_frequency with trace_policy_frequency
cpufreq: Documentation update for trace_policy_frequency
Documentation/admin-guide/pm/amd-pstate.rst | 10 ++++----
Documentation/admin-guide/pm/intel_pstate.rst | 14 +++++------
Documentation/trace/events-power.rst | 2 +-
drivers/cpufreq/cpufreq.c | 14 ++---------
drivers/cpufreq/intel_pstate.c | 6 +++--
include/trace/events/power.h | 24 ++++++++++++++++---
kernel/trace/power-traces.c | 2 +-
samples/bpf/cpustat_kern.c | 8 +++----
samples/bpf/cpustat_user.c | 6 ++---
tools/perf/builtin-timechart.c | 12 +++++-----
10 files changed, 54 insertions(+), 44 deletions(-)
--
2.52.0.107.ga0afd4fd5b-goog
