perf test: Add workload-ctl option

Add a --workload-ctl=fifo:ctl-fifo[,ack-fifo] option for 'perf test
-w'. When set, run_workload() opens the named FIFO, writes enable before
invoking the builtin workload, writes disable before returning, and
waits for ack responses when an ack FIFO is provided to ensure that the
workload doesn't run until the events are enabled.

This can be used to limit the scope of the recording to only the
workload execution and avoid recording Perf setup and teardown code if
Perf record is started with events disabled (-D 1).

Assisted-by: Codex:GPT-5.5
Signed-off-by: James Clark <james.clark@linaro.org>
Cc: Amir Ayupov <aaupov@meta.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leo Yan <leo.yan@arm.com>
Cc: Mike Leach <mike.leach@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paschalis Mpeis <Paschalis.Mpeis@arm.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/tools/perf/Documentation/perf-test.txt b/tools/perf/Documentation/perf-test.txt
index 32da0d1fa86a..2f4a91f5b9dc 100644
--- a/tools/perf/Documentation/perf-test.txt
+++ b/tools/perf/Documentation/perf-test.txt
@@ -69,3 +69,15 @@ OPTIONS
 
 --list-workloads::
 	List the available workloads to use with -w/--workload.
+
+--record-ctl=fifo:ctl-fifo[,ack-fifo]::
+	This option is used to communicate with a perf record session in order
+	to control the recording scope to only the workload and avoid recording
+	setup and teardown code. When specifying this option, the same FIFO path
+	must be specified in the record session via:
+
+	  perf record -D -1 --control=fifo:ctl-fifo[,ack-fifo] ...
+
+	Perf test sends 'enable' and 'disable' commands through ctl-fifo to
+	control event recording. If 'ack-fifo' is provided, the workload runner
+	waits for an 'ack' response after each command.