[PATCH v4 4/4] perf record: implement --affinity=node|cpu option

[Alexey Budankov]

Implement --affinity=node|cpu option for the record mode defaulting
to system affinity mask bouncing.

Signed-off-by: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx>
---
changes in v3:
- adjusted indentation at record__parse_affinity()
---
 tools/perf/Documentation/perf-record.txt |  5 +++++
 tools/perf/builtin-record.c              | 20 ++++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index d232b13ea713..efb839784f32 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -440,6 +440,11 @@ Use <n> control blocks in asynchronous (Posix AIO) trace writing mode (default:
 Asynchronous mode is supported only when linking Perf tool with libc library
 providing implementation for Posix AIO API.
 
+--affinity=mode::
+Set affinity mask of trace reading thread according to the policy defined by 'mode' value:
+  node - thread affinity mask is set to NUMA node cpu mask of the processed mmap buffer
+  cpu  - thread affinity mask is set to cpu of the processed mmap buffer
+
 --all-kernel::
 Configure all used events to run in kernel space.
 
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 553c2fabf3c1..94a966ba9a6f 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -1659,6 +1659,23 @@ static int parse_clockid(const struct option *opt, const char *str, int unset)
 	return -1;
 }
 
+static int record__parse_affinity(const struct option *opt, const char *str, int unset)
+{
+	struct record_opts *opts = (struct record_opts *)opt->value;
+
+	if (unset)
+		return 0;
+
+	if (str) {
+		if (!strcasecmp(str, "node"))
+			opts->affinity = PERF_AFFINITY_NODE;
+		else if (!strcasecmp(str, "cpu"))
+			opts->affinity = PERF_AFFINITY_CPU;
+	}
+
+	return 0;
+}
+
 static int record__parse_mmap_pages(const struct option *opt,
 				    const char *str,
 				    int unset __maybe_unused)
@@ -1966,6 +1983,9 @@ static struct option __record_options[] = {
 		     &nr_cblocks_default, "n", "Use <n> control blocks in asynchronous trace writing mode (default: 1, max: 4)",
 		     record__aio_parse),
 #endif
+	OPT_CALLBACK(0, "affinity", &record.opts, "node|cpu",
+		     "Set affinity mask of trace reading thread to NUMA node cpu mask or cpu of processed mmap buffer",
+		     record__parse_affinity),
 	OPT_END()
 };