[v8,21/25] trace-cmd library: Handle latency trace in version 7 files

Commit Message

Tzvetomir Stoyanov (VMware) Jan. 19, 2022, 8:25 a.m. UTC

Latency trace data is saved the same was as flyrecord buffer data
in trace files version 7. There is a BUFFER_TEXT option which holds the
latency specific trace metadata and points to the section in the file
with the trace data. A new API is added to read latency data:
 tracecmd_latency_data_read()

Signed-off-by: Tzvetomir Stoyanov (VMware) <[e-mail]>
---
 .../include/private/trace-cmd-private.h       |  5 +++-
 lib/trace-cmd/trace-input.c                   | 29 ++++++++++++++++++-
 lib/trace-cmd/trace-output.c                  |  5 +++-
 tracecmd/trace-record.c                       |  3 +-
 4 files changed, 38 insertions(+), 4 deletions(-)

Patch

diff --git a/lib/trace-cmd/include/private/trace-cmd-private.h b/lib/trace-cmd/include/private/trace-cmd-private.h
index 94b33949..1efafba1 100644
--- a/lib/trace-cmd/include/private/trace-cmd-private.h
+++ b/lib/trace-cmd/include/private/trace-cmd-private.h
@@ -227,6 +227,8 @@  tracecmd_peek_data_ref(struct tracecmd_input *handle, int cpu)
 	return rec;
 }
 
+int tracecmd_latency_data_read(struct tracecmd_input *handle, char **buf, size_t *size);
+
 struct tep_record *
 tracecmd_read_prev(struct tracecmd_input *handle, struct tep_record *record);
 
@@ -301,7 +303,8 @@  int tracecmd_output_write_headers(struct tracecmd_output *handle,
 
 struct tracecmd_output *tracecmd_output_create(const char *output_file);
 struct tracecmd_output *tracecmd_output_create_fd(int fd);
-struct tracecmd_output *tracecmd_create_file_latency(const char *output_file, int cpus);
+struct tracecmd_output *tracecmd_create_file_latency(const char *output_file, int cpus,
+						     int file_version);
 
 struct tracecmd_option *tracecmd_add_option(struct tracecmd_output *handle,
 					    unsigned short id, int size,
diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
index 103ff7bf..6f540c90 100644
--- a/lib/trace-cmd/trace-input.c
+++ b/lib/trace-cmd/trace-input.c
@@ -3214,6 +3214,24 @@  static int read_options_type(struct tracecmd_input *handle)
 	return 0;
 }
 
+int tracecmd_latency_data_read(struct tracecmd_input *handle, char **buf, size_t *size)
+{
+	if (!handle || !buf || !size)
+		return -1;
+	if (handle->file_state != TRACECMD_FILE_CPU_LATENCY)
+		return -1;
+
+	/* Read data from a file */
+	if (!(*buf)) {
+		*size = BUFSIZ;
+		*buf = malloc(*size);
+		if (!(*buf))
+			return -1;
+	}
+
+	return do_read(handle, *buf, *size);
+}
+
 static int init_cpu_data(struct tracecmd_input *handle)
 {
 	enum kbuffer_long_size long_size;
@@ -3276,6 +3294,12 @@  static int init_cpu_data(struct tracecmd_input *handle)
 	return -1;
 }
 
+int init_latency_data(struct tracecmd_input *handle)
+{
+	/* To do */
+	return 0;
+}
+
 static int init_buffer_cpu_data(struct tracecmd_input *handle, struct input_buffer_instance *buffer)
 {
 	unsigned long long offset;
@@ -3290,7 +3314,10 @@  static int init_buffer_cpu_data(struct tracecmd_input *handle, struct input_buff
 		return -1;
 	if (read_section_header(handle, &id, &flags, NULL, NULL))
 		return -1;
-
+	if (buffer->latency) {
+		handle->file_state = TRACECMD_FILE_CPU_LATENCY;
+		return init_latency_data(handle) == 0 ? 1 : -1;
+	}
 	handle->file_state = TRACECMD_FILE_CPU_FLYRECORD;
 	handle->cpus = buffer->cpus;
 	if (handle->max_cpu < handle->cpus)
diff --git a/lib/trace-cmd/trace-output.c b/lib/trace-cmd/trace-output.c
index fe4fcf64..15baef8f 100644
--- a/lib/trace-cmd/trace-output.c
+++ b/lib/trace-cmd/trace-output.c
@@ -1890,7 +1890,8 @@  out_add_buffer_option(struct tracecmd_output *handle, const char *name,
 	return option;
 }
 
-struct tracecmd_output *tracecmd_create_file_latency(const char *output_file, int cpus)
+struct tracecmd_output *tracecmd_create_file_latency(const char *output_file, int cpus,
+						     int file_version)
 {
 	enum tracecmd_section_flags flags = 0;
 	struct tracecmd_output *handle;
@@ -1901,6 +1902,8 @@  struct tracecmd_output *tracecmd_create_file_latency(const char *output_file, in
 	if (!handle)
 		return NULL;
 
+	if (file_version && tracecmd_output_set_version(handle, file_version))
+		goto out_free;
 	if (tracecmd_output_write_headers(handle, NULL))
 		goto out_free;
 	/*
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index f599610e..2dea79dc 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -4501,7 +4501,8 @@  static void record_data(struct common_record_context *ctx)
 		return;
 
 	if (latency) {
-		handle = tracecmd_create_file_latency(ctx->output, local_cpu_count);
+		handle = tracecmd_create_file_latency(ctx->output, local_cpu_count,
+						      ctx->file_version);
 		tracecmd_set_quiet(handle, quiet);
 	} else {
 		if (!local_cpu_count)