[v18,10/18] trace-cmd: Store the session tracing ID in the trace.dat file
diff mbox series

Message ID 20191213153029.133570-11-tz.stoyanov@gmail.com
State Superseded
Headers show
Series
  • Timestamp synchronization of host - guest tracing session
Related show

Commit Message

Tzvetomir Stoyanov (VMware) Dec. 13, 2019, 3:30 p.m. UTC
The ID of the current tracing session is stored in the trace.dat file.
A new file option is introduced:
	TRACECMD_OPTION_TRACEID
The data is stored in the file as NULL terminated string:
	"\nTraceID: %llu\n"
A new libtracecmd API is introduced, to get the ID when the trace.dat file is read:
	unsigned long long tracecmd_get_traceid(struct tracecmd_input *handle);

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 include/trace-cmd/trace-cmd.h |  2 ++
 lib/trace-cmd/trace-input.c   | 25 +++++++++++++++++++++++++
 tracecmd/trace-record.c       | 15 +++++++++++++++
 3 files changed, 42 insertions(+)

Comments

Steven Rostedt Dec. 20, 2019, 8:04 p.m. UTC | #1
On Fri, 13 Dec 2019 17:30:21 +0200
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:

> The ID of the current tracing session is stored in the trace.dat file.
> A new file option is introduced:
> 	TRACECMD_OPTION_TRACEID
> The data is stored in the file as NULL terminated string:
> 	"\nTraceID: %llu\n"

If the trace ID is just a 64 bit number, why is it stored in the file
as a string?

-- Steve


> A new libtracecmd API is introduced, to get the ID when the trace.dat file is read:
> 	unsigned long long tracecmd_get_traceid(struct tracecmd_input *handle);
> 
> Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
> ---
>  include/trace-cmd/trace-cmd.h |  2 ++
>  lib/trace-cmd/trace-input.c   | 25 +++++++++++++++++++++++++
>  tracecmd/trace-record.c       | 15 +++++++++++++++
>  3 files changed, 42 insertions(+)
> 
> diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
> index ad69313..6cc2913 100644
> --- a/include/trace-cmd/trace-cmd.h
> +++ b/include/trace-cmd/trace-cmd.h
> @@ -86,6 +86,7 @@ enum {
>  	TRACECMD_OPTION_CPUCOUNT,
>  	TRACECMD_OPTION_VERSION,
>  	TRACECMD_OPTION_PROCMAPS,
> +	TRACECMD_OPTION_TRACEID,
>  };
>  
>  enum {
> @@ -128,6 +129,7 @@ int tracecmd_copy_headers(struct tracecmd_input *handle, int fd);
>  void tracecmd_set_flag(struct tracecmd_input *handle, int flag);
>  void tracecmd_clear_flag(struct tracecmd_input *handle, int flag);
>  unsigned long tracecmd_get_flags(struct tracecmd_input *handle);
> +unsigned long long tracecmd_get_traceid(struct tracecmd_input *handle);
>  
>  void tracecmd_parse_trace_clock(struct tracecmd_input *handle, char *file, int size);
>  
> diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
> index 91362f3..40d9825 100644
> --- a/lib/trace-cmd/trace-input.c
> +++ b/lib/trace-cmd/trace-input.c
> @@ -79,6 +79,7 @@ struct tracecmd_input {
>  	struct tep_plugin_list	*plugin_list;
>  	struct tracecmd_input	*parent;
>  	unsigned long		flags;
> +	unsigned long long	trace_id;
>  	int			fd;
>  	int			long_size;
>  	int			page_size;
> @@ -2169,6 +2170,15 @@ static void procmap_free(struct pid_addr_maps *maps)
>  	free(maps);
>  }
>  
> +static int trace_traceid_load(struct tracecmd_input *handle, char *buf)
> +{
> +
> +	if (sscanf(buf, "%*s %llu", &handle->trace_id) == 1)
> +		return 0;
> +
> +	return -1;
> +}
> +
>  #define STR_PROCMAP_LINE_MAX	(PATH_MAX+22)
>  static int trace_pid_map_load(struct tracecmd_input *handle, char *buf)
>  {
> @@ -2406,6 +2416,10 @@ static int handle_options(struct tracecmd_input *handle)
>  			if (buf[size-1] == '\0')
>  				trace_pid_map_load(handle, buf);
>  			break;
> +		case TRACECMD_OPTION_TRACEID:
> +			if (buf[size-1] == '\0')
> +				trace_traceid_load(handle, buf);
> +			break;
>  		default:
>  			warning("unknown option %d", option);
>  			break;
> @@ -3507,3 +3521,14 @@ void tracecmd_set_show_data_func(struct tracecmd_input *handle,
>  {
>  	handle->show_data_func = func;
>  }
> +
> +/**
> + * tracecmd_get_traceid - get the trace id of the session
> + * @handle: input handle for the trace.dat file
> + *
> + * Returns the trace id, written in the trace file
> + */
> +unsigned long long tracecmd_get_traceid(struct tracecmd_input *handle)
> +{
> +	return handle->trace_id;
> +}
> diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
> index 7089f7b..b65aeb2 100644
> --- a/tracecmd/trace-record.c
> +++ b/tracecmd/trace-record.c
> @@ -3714,6 +3714,19 @@ add_pid_maps(struct tracecmd_output *handle, struct buffer_instance *instance)
>  	trace_seq_destroy(&s);
>  }
>  
> +static void
> +add_trace_id(struct tracecmd_output *handle, struct buffer_instance *instance)
> +{
> +	char *str = NULL;
> +	int len;
> +
> +	len = asprintf(&str, "\nTraceID: %llu\n", instance->trace_id);
> +	if (len < 1)
> +		return;
> +	tracecmd_add_option(handle, TRACECMD_OPTION_TRACEID, len + 1, str);
> +	free(str);
> +}
> +
>  static void
>  add_buffer_stat(struct tracecmd_output *handle, struct buffer_instance *instance)
>  {
> @@ -3817,6 +3830,8 @@ static void add_options(struct tracecmd_output *handle, struct common_record_con
>  	add_option_hooks(handle);
>  	add_uname(handle);
>  	add_version(handle);
> +	if (!no_top_instance())
> +		add_trace_id(handle, &top_instance);
>  }
>  
>  static void write_guest_file(struct buffer_instance *instance)
Tzvetomir Stoyanov (VMware) Jan. 6, 2020, 2:33 p.m. UTC | #2
On Fri, Dec 20, 2019 at 10:04 PM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Fri, 13 Dec 2019 17:30:21 +0200
> "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:
>
> > The ID of the current tracing session is stored in the trace.dat file.
> > A new file option is introduced:
> >       TRACECMD_OPTION_TRACEID
> > The data is stored in the file as NULL terminated string:
> >       "\nTraceID: %llu\n"
>
> If the trace ID is just a 64 bit number, why is it stored in the file
> as a string?
>

The only reason for this is to avoid endian long long conversions,
and to simplify reading of trace.dat file, for debug purposes.

> -- Steve
>
>
> > A new libtracecmd API is introduced, to get the ID when the trace.dat file is read:
> >       unsigned long long tracecmd_get_traceid(struct tracecmd_input *handle);
> >
> > Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
> > ---
> >  include/trace-cmd/trace-cmd.h |  2 ++
> >  lib/trace-cmd/trace-input.c   | 25 +++++++++++++++++++++++++
> >  tracecmd/trace-record.c       | 15 +++++++++++++++
> >  3 files changed, 42 insertions(+)
> >
> > diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
> > index ad69313..6cc2913 100644
> > --- a/include/trace-cmd/trace-cmd.h
> > +++ b/include/trace-cmd/trace-cmd.h
> > @@ -86,6 +86,7 @@ enum {
> >       TRACECMD_OPTION_CPUCOUNT,
> >       TRACECMD_OPTION_VERSION,
> >       TRACECMD_OPTION_PROCMAPS,
> > +     TRACECMD_OPTION_TRACEID,
> >  };
> >
> >  enum {
> > @@ -128,6 +129,7 @@ int tracecmd_copy_headers(struct tracecmd_input *handle, int fd);
> >  void tracecmd_set_flag(struct tracecmd_input *handle, int flag);
> >  void tracecmd_clear_flag(struct tracecmd_input *handle, int flag);
> >  unsigned long tracecmd_get_flags(struct tracecmd_input *handle);
> > +unsigned long long tracecmd_get_traceid(struct tracecmd_input *handle);
> >
> >  void tracecmd_parse_trace_clock(struct tracecmd_input *handle, char *file, int size);
> >
> > diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
> > index 91362f3..40d9825 100644
> > --- a/lib/trace-cmd/trace-input.c
> > +++ b/lib/trace-cmd/trace-input.c
> > @@ -79,6 +79,7 @@ struct tracecmd_input {
> >       struct tep_plugin_list  *plugin_list;
> >       struct tracecmd_input   *parent;
> >       unsigned long           flags;
> > +     unsigned long long      trace_id;
> >       int                     fd;
> >       int                     long_size;
> >       int                     page_size;
> > @@ -2169,6 +2170,15 @@ static void procmap_free(struct pid_addr_maps *maps)
> >       free(maps);
> >  }
> >
> > +static int trace_traceid_load(struct tracecmd_input *handle, char *buf)
> > +{
> > +
> > +     if (sscanf(buf, "%*s %llu", &handle->trace_id) == 1)
> > +             return 0;
> > +
> > +     return -1;
> > +}
> > +
> >  #define STR_PROCMAP_LINE_MAX (PATH_MAX+22)
> >  static int trace_pid_map_load(struct tracecmd_input *handle, char *buf)
> >  {
> > @@ -2406,6 +2416,10 @@ static int handle_options(struct tracecmd_input *handle)
> >                       if (buf[size-1] == '\0')
> >                               trace_pid_map_load(handle, buf);
> >                       break;
> > +             case TRACECMD_OPTION_TRACEID:
> > +                     if (buf[size-1] == '\0')
> > +                             trace_traceid_load(handle, buf);
> > +                     break;
> >               default:
> >                       warning("unknown option %d", option);
> >                       break;
> > @@ -3507,3 +3521,14 @@ void tracecmd_set_show_data_func(struct tracecmd_input *handle,
> >  {
> >       handle->show_data_func = func;
> >  }
> > +
> > +/**
> > + * tracecmd_get_traceid - get the trace id of the session
> > + * @handle: input handle for the trace.dat file
> > + *
> > + * Returns the trace id, written in the trace file
> > + */
> > +unsigned long long tracecmd_get_traceid(struct tracecmd_input *handle)
> > +{
> > +     return handle->trace_id;
> > +}
> > diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
> > index 7089f7b..b65aeb2 100644
> > --- a/tracecmd/trace-record.c
> > +++ b/tracecmd/trace-record.c
> > @@ -3714,6 +3714,19 @@ add_pid_maps(struct tracecmd_output *handle, struct buffer_instance *instance)
> >       trace_seq_destroy(&s);
> >  }
> >
> > +static void
> > +add_trace_id(struct tracecmd_output *handle, struct buffer_instance *instance)
> > +{
> > +     char *str = NULL;
> > +     int len;
> > +
> > +     len = asprintf(&str, "\nTraceID: %llu\n", instance->trace_id);
> > +     if (len < 1)
> > +             return;
> > +     tracecmd_add_option(handle, TRACECMD_OPTION_TRACEID, len + 1, str);
> > +     free(str);
> > +}
> > +
> >  static void
> >  add_buffer_stat(struct tracecmd_output *handle, struct buffer_instance *instance)
> >  {
> > @@ -3817,6 +3830,8 @@ static void add_options(struct tracecmd_output *handle, struct common_record_con
> >       add_option_hooks(handle);
> >       add_uname(handle);
> >       add_version(handle);
> > +     if (!no_top_instance())
> > +             add_trace_id(handle, &top_instance);
> >  }
> >
> >  static void write_guest_file(struct buffer_instance *instance)
>

Patch
diff mbox series

diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
index ad69313..6cc2913 100644
--- a/include/trace-cmd/trace-cmd.h
+++ b/include/trace-cmd/trace-cmd.h
@@ -86,6 +86,7 @@  enum {
 	TRACECMD_OPTION_CPUCOUNT,
 	TRACECMD_OPTION_VERSION,
 	TRACECMD_OPTION_PROCMAPS,
+	TRACECMD_OPTION_TRACEID,
 };
 
 enum {
@@ -128,6 +129,7 @@  int tracecmd_copy_headers(struct tracecmd_input *handle, int fd);
 void tracecmd_set_flag(struct tracecmd_input *handle, int flag);
 void tracecmd_clear_flag(struct tracecmd_input *handle, int flag);
 unsigned long tracecmd_get_flags(struct tracecmd_input *handle);
+unsigned long long tracecmd_get_traceid(struct tracecmd_input *handle);
 
 void tracecmd_parse_trace_clock(struct tracecmd_input *handle, char *file, int size);
 
diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
index 91362f3..40d9825 100644
--- a/lib/trace-cmd/trace-input.c
+++ b/lib/trace-cmd/trace-input.c
@@ -79,6 +79,7 @@  struct tracecmd_input {
 	struct tep_plugin_list	*plugin_list;
 	struct tracecmd_input	*parent;
 	unsigned long		flags;
+	unsigned long long	trace_id;
 	int			fd;
 	int			long_size;
 	int			page_size;
@@ -2169,6 +2170,15 @@  static void procmap_free(struct pid_addr_maps *maps)
 	free(maps);
 }
 
+static int trace_traceid_load(struct tracecmd_input *handle, char *buf)
+{
+
+	if (sscanf(buf, "%*s %llu", &handle->trace_id) == 1)
+		return 0;
+
+	return -1;
+}
+
 #define STR_PROCMAP_LINE_MAX	(PATH_MAX+22)
 static int trace_pid_map_load(struct tracecmd_input *handle, char *buf)
 {
@@ -2406,6 +2416,10 @@  static int handle_options(struct tracecmd_input *handle)
 			if (buf[size-1] == '\0')
 				trace_pid_map_load(handle, buf);
 			break;
+		case TRACECMD_OPTION_TRACEID:
+			if (buf[size-1] == '\0')
+				trace_traceid_load(handle, buf);
+			break;
 		default:
 			warning("unknown option %d", option);
 			break;
@@ -3507,3 +3521,14 @@  void tracecmd_set_show_data_func(struct tracecmd_input *handle,
 {
 	handle->show_data_func = func;
 }
+
+/**
+ * tracecmd_get_traceid - get the trace id of the session
+ * @handle: input handle for the trace.dat file
+ *
+ * Returns the trace id, written in the trace file
+ */
+unsigned long long tracecmd_get_traceid(struct tracecmd_input *handle)
+{
+	return handle->trace_id;
+}
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 7089f7b..b65aeb2 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -3714,6 +3714,19 @@  add_pid_maps(struct tracecmd_output *handle, struct buffer_instance *instance)
 	trace_seq_destroy(&s);
 }
 
+static void
+add_trace_id(struct tracecmd_output *handle, struct buffer_instance *instance)
+{
+	char *str = NULL;
+	int len;
+
+	len = asprintf(&str, "\nTraceID: %llu\n", instance->trace_id);
+	if (len < 1)
+		return;
+	tracecmd_add_option(handle, TRACECMD_OPTION_TRACEID, len + 1, str);
+	free(str);
+}
+
 static void
 add_buffer_stat(struct tracecmd_output *handle, struct buffer_instance *instance)
 {
@@ -3817,6 +3830,8 @@  static void add_options(struct tracecmd_output *handle, struct common_record_con
 	add_option_hooks(handle);
 	add_uname(handle);
 	add_version(handle);
+	if (!no_top_instance())
+		add_trace_id(handle, &top_instance);
 }
 
 static void write_guest_file(struct buffer_instance *instance)