[v8,11/25] trace-cmd library: Fit CPU latency trace data in the new trace file version 7 format

Commit Message

Tzvetomir Stoyanov (VMware) Jan. 19, 2022, 8:24 a.m. UTC

Trace file version 7 format is based on sections. To fit the latency
trace data in this structure, a new section and option for it is
defined:
  BUFFER_TEXT

It is similar to the BUFFER section which holds the flyrecord binary
data, but has a latency specific design for text data. The BUFFER_TEXT
section has:
 - section header, as all other sections
 - compression of the trace data, optional
 - corresponding trace option, pointing to the section

Signed-off-by: Tzvetomir Stoyanov (VMware) <[e-mail]>
---
 .../include/private/trace-cmd-private.h       |  1 +
 lib/trace-cmd/trace-output.c                  | 20 +++++++++++++++++--
 2 files changed, 19 insertions(+), 2 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 eaf51f5f..953297f3 100644
--- a/lib/trace-cmd/include/private/trace-cmd-private.h
+++ b/lib/trace-cmd/include/private/trace-cmd-private.h
@@ -150,6 +150,7 @@  enum {
 	TRACECMD_OPTION_KALLSYMS,
 	TRACECMD_OPTION_PRINTK,
 	TRACECMD_OPTION_CMDLINES,
+	TRACECMD_OPTION_BUFFER_TEXT,
 	TRACECMD_OPTION_MAX,
 };
 
diff --git a/lib/trace-cmd/trace-output.c b/lib/trace-cmd/trace-output.c
index 30bf0dd1..7e1849c8 100644
--- a/lib/trace-cmd/trace-output.c
+++ b/lib/trace-cmd/trace-output.c
@@ -1892,7 +1892,9 @@  out_add_buffer_option(struct tracecmd_output *handle, const char *name,
 
 struct tracecmd_output *tracecmd_create_file_latency(const char *output_file, int cpus)
 {
+	enum tracecmd_section_flags flags = 0;
 	struct tracecmd_output *handle;
+	tsize_t offset;
 	char *path;
 
 	handle = tracecmd_output_create(output_file);
@@ -1909,7 +1911,8 @@  struct tracecmd_output *tracecmd_create_file_latency(const char *output_file, in
 
 	if (tracecmd_write_cpus(handle, cpus) < 0)
 		goto out_free;
-
+	if (tracecmd_write_buffer_info(handle) < 0)
+		goto out_free;
 	if (tracecmd_write_options(handle) < 0)
 		goto out_free;
 
@@ -1919,19 +1922,32 @@  struct tracecmd_output *tracecmd_create_file_latency(const char *output_file, in
 		goto out_free;
 	}
 
-	if (do_write_check(handle, "latency  ", 10))
+	if (!HAS_SECTIONS(handle) && do_write_check(handle, "latency  ", 10))
 		goto out_free;
 
 	path = get_tracing_file(handle, "trace");
 	if (!path)
 		goto out_free;
 
+	offset = do_lseek(handle, 0, SEEK_CUR);
+	if (HAS_SECTIONS(handle) &&
+	    !out_add_buffer_option(handle, "", TRACECMD_OPTION_BUFFER_TEXT, offset, 0, NULL))
+		goto out_free;
+
+	offset = out_write_section_header(handle, TRACECMD_OPTION_BUFFER_TEXT,
+					  "buffer latency", flags, false);
+
 	copy_file(handle, path);
+	if (out_update_section_header(handle, offset))
+		goto out_free;
 
 	put_tracing_file(path);
 
 	handle->file_state = TRACECMD_FILE_CPU_LATENCY;
 
+	if (HAS_SECTIONS(handle))
+		tracecmd_write_options(handle);
+
 	return handle;
 
 out_free: