[PATCH v6 0/2] perf: add support for logging debug messages to file

[PATCH v6 0/2] perf: add support for logging debug messages to file

[Changbin Du]

When in TUI mode, it is impossible to show all the debug messages to
console. This make it hard to debug perf issues using debug messages.
This patch adds support for logging debug messages to file to resolve
this problem.

v6:
  o rebase to perf/core.
v5:
  o doc default log path.
v4:
  o fix another segfault.
v3:
  o fix a segfault issue.
v2:
  o specific all debug options one time.

Changbin Du (2):
  perf: support multiple debug options separated by ','
  perf: add support for logging debug messages to file

 tools/perf/Documentation/perf.txt |  20 +++--
 tools/perf/util/debug.c           | 127 ++++++++++++++++++++----------
 2 files changed, 96 insertions(+), 51 deletions(-)

-- 
2.20.1

[PATCH v6 1/2] perf: support multiple debug options separated by ','

[Changbin Du]

This patch adds support for multiple debug options separated by ',' and
non-int values.
	--debug verbose=2,stderr

Signed-off-by: Changbin Du <changbin.du@gmail.com>
---
 tools/perf/Documentation/perf.txt | 13 +++--
 tools/perf/util/debug.c           | 89 ++++++++++++++++---------------
 2 files changed, 53 insertions(+), 49 deletions(-)

diff --git a/tools/perf/Documentation/perf.txt b/tools/perf/Documentation/perf.txt
index 3f37ded13f8c..fd8d790f68a7 100644
--- a/tools/perf/Documentation/perf.txt
+++ b/tools/perf/Documentation/perf.txt
@@ -19,13 +19,12 @@ OPTIONS
 	  --debug verbose=2 # sets verbose = 2
 
 	List of debug variables allowed to set:
-	  verbose          - general debug messages
-	  ordered-events   - ordered events object debug messages
-	  data-convert     - data convert command debug messages
-	  stderr           - write debug output (option -v) to stderr
-	                     in browser mode
-	  perf-event-open  - Print perf_event_open() arguments and
-			     return value
+	  verbose=level		- general debug messages
+	  ordered-events=level	- ordered events object debug messages
+	  data-convert=level	- data convert command debug messages
+	  stderr		- write debug output (option -v) to stderr
+	  perf-event-open	- Print perf_event_open() arguments and
+	                          return value in browser mode
 
 --buildid-dir::
 	Setup buildid cache directory. It has higher priority than
diff --git a/tools/perf/util/debug.c b/tools/perf/util/debug.c
index adb656745ecc..929da46ece92 100644
--- a/tools/perf/util/debug.c
+++ b/tools/perf/util/debug.c
@@ -27,7 +27,7 @@ int verbose;
 int debug_peo_args;
 bool dump_trace = false, quiet = false;
 int debug_ordered_events;
-static int redirect_to_stderr;
+static bool redirect_to_stderr;
 int debug_data_convert;
 
 int veprintf(int level, int var, const char *fmt, va_list args)
@@ -173,42 +173,18 @@ void trace_event(union perf_event *event)
 		     trace_event_printer, event);
 }
 
-static struct debug_variable {
-	const char *name;
-	int *ptr;
-} debug_variables[] = {
-	{ .name = "verbose",		.ptr = &verbose },
-	{ .name = "ordered-events",	.ptr = &debug_ordered_events},
-	{ .name = "stderr",		.ptr = &redirect_to_stderr},
-	{ .name = "data-convert",	.ptr = &debug_data_convert },
-	{ .name = "perf-event-open",	.ptr = &debug_peo_args },
-	{ .name = NULL, }
-};
-
-int perf_debug_option(const char *str)
+static int str2loglevel(const char *vstr)
 {
-	struct debug_variable *var = &debug_variables[0];
-	char *vstr, *s = strdup(str);
 	int v = 1;
-
-	vstr = strchr(s, '=');
-	if (vstr)
-		*vstr++ = 0;
-
-	while (var->name) {
-		if (!strcmp(s, var->name))
-			break;
-		var++;
-	}
-
-	if (!var->name) {
-		pr_err("Unknown debug variable name '%s'\n", s);
-		free(s);
-		return -1;
-	}
+	char *endptr;
 
 	if (vstr) {
-		v = atoi(vstr);
+		v = strtol(vstr, &endptr,0);
+		if (vstr == endptr) {
+			fprintf(stderr, "warning: '%s' is not a digit\n", vstr);
+			return -1;
+		}
+
 		/*
 		 * Allow only values in range (0, 10),
 		 * otherwise set 0.
@@ -219,20 +195,49 @@ int perf_debug_option(const char *str)
 	if (quiet)
 		v = -1;
 
-	*var->ptr = v;
-	free(s);
+	return v;
+}
+
+int perf_debug_option(const char *str)
+{
+	char *sep, *vstr;
+	char *dstr = strdup(str);
+	char *opt = dstr;
+
+	do {
+		if ((sep = strchr(opt, ',')) != NULL)
+			*sep = '\0';
+
+		vstr = strchr(opt, '=');
+		if (vstr)
+			*vstr++ = 0;
+
+		if (!strcmp(opt, "verbose"))
+			verbose = str2loglevel(vstr);
+		else if (!strcmp(opt, "ordered-events"))
+			debug_ordered_events = str2loglevel(vstr);
+		else if (!strcmp(opt, "data-convert"))
+			debug_data_convert = str2loglevel(vstr);
+		else if (!strcmp(opt, "stderr"))
+			redirect_to_stderr = true;
+		else if (!strcmp(opt, "perf-event-open"))
+			debug_peo_args = true;
+		else {
+			fprintf(stderr, "unkown debug option '%s'\n", opt);
+			free(dstr);
+			return -1;
+		}
+
+		opt = sep + 1;
+	} while (sep && sep[1]);
+
+	free(dstr);
 	return 0;
 }
 
 int perf_quiet_option(void)
 {
-	struct debug_variable *var = &debug_variables[0];
-
-	/* disable all debug messages */
-	while (var->name) {
-		*var->ptr = -1;
-		var++;
-	}
+	verbose = debug_ordered_events = debug_data_convert = -1;
 
 	return 0;
 }
-- 
2.20.1

Re: [PATCH v6 1/2] perf: support multiple debug options separated by ','

[Ravi Bangoria]

On 11/25/19 8:44 PM, Changbin Du wrote:
>   	List of debug variables allowed to set:
> -	  verbose          - general debug messages
> -	  ordered-events   - ordered events object debug messages
> -	  data-convert     - data convert command debug messages
> -	  stderr           - write debug output (option -v) to stderr
> -	                     in browser mode
> -	  perf-event-open  - Print perf_event_open() arguments and
> -			     return value
> +	  verbose=level		- general debug messages
> +	  ordered-events=level	- ordered events object debug messages
> +	  data-convert=level	- data convert command debug messages
> +	  stderr		- write debug output (option -v) to stderr
> +	  perf-event-open	- Print perf_event_open() arguments and
> +	                          return value in browser mode
Shouldn't this be:

	  stderr		- write debug output (option -v) to stderr
	  			  in browser mode
	  perf-event-open	- Print perf_event_open() arguments and
	                          return value

-Ravi

Re: [PATCH v6 1/2] perf: support multiple debug options separated by ','

[Changbin Du]

On Tue, Nov 26, 2019 at 11:10:45AM +0530, Ravi Bangoria wrote:
> 
> 
> On 11/25/19 8:44 PM, Changbin Du wrote:
> >   	List of debug variables allowed to set:
> > -	  verbose          - general debug messages
> > -	  ordered-events   - ordered events object debug messages
> > -	  data-convert     - data convert command debug messages
> > -	  stderr           - write debug output (option -v) to stderr
> > -	                     in browser mode
> > -	  perf-event-open  - Print perf_event_open() arguments and
> > -			     return value
> > +	  verbose=level		- general debug messages
> > +	  ordered-events=level	- ordered events object debug messages
> > +	  data-convert=level	- data convert command debug messages
> > +	  stderr		- write debug output (option -v) to stderr
> > +	  perf-event-open	- Print perf_event_open() arguments and
> > +	                          return value in browser mode
> Shouldn't this be:
> 
> 	  stderr		- write debug output (option -v) to stderr
> 	  			  in browser mode
> 	  perf-event-open	- Print perf_event_open() arguments and
> 	                          return value
> 
This is an accident when rebasing. Thank you.

> -Ravi
> 

-- 
Cheers,
Changbin Du

Re: [PATCH v6 1/2] perf: support multiple debug options separated by ','

[Jiri Olsa]

On Mon, Nov 25, 2019 at 11:14:45PM +0800, Changbin Du wrote:
> This patch adds support for multiple debug options separated by ',' and
> non-int values.
> 	--debug verbose=2,stderr
> 
> Signed-off-by: Changbin Du <changbin.du@gmail.com>
> ---
>  tools/perf/Documentation/perf.txt | 13 +++--
>  tools/perf/util/debug.c           | 89 ++++++++++++++++---------------
>  2 files changed, 53 insertions(+), 49 deletions(-)
> 
> diff --git a/tools/perf/Documentation/perf.txt b/tools/perf/Documentation/perf.txt
> index 3f37ded13f8c..fd8d790f68a7 100644
> --- a/tools/perf/Documentation/perf.txt
> +++ b/tools/perf/Documentation/perf.txt
> @@ -19,13 +19,12 @@ OPTIONS
>  	  --debug verbose=2 # sets verbose = 2
>  
>  	List of debug variables allowed to set:
> -	  verbose          - general debug messages
> -	  ordered-events   - ordered events object debug messages
> -	  data-convert     - data convert command debug messages
> -	  stderr           - write debug output (option -v) to stderr
> -	                     in browser mode
> -	  perf-event-open  - Print perf_event_open() arguments and
> -			     return value
> +	  verbose=level		- general debug messages
> +	  ordered-events=level	- ordered events object debug messages
> +	  data-convert=level	- data convert command debug messages
> +	  stderr		- write debug output (option -v) to stderr
> +	  perf-event-open	- Print perf_event_open() arguments and
> +	                          return value in browser mode

it's just the list and the doc says user can use values
there, so no need for the '=level' there

also we allow this:
  perf --debug stderr=9 record ls

so I thinks we should keep it general in documentation,
eventhough it will always mean just stderr=true for any
value

jirka

Re: [PATCH v6 1/2] perf: support multiple debug options separated by ','

[Changbin Du]

On Tue, Nov 26, 2019 at 10:45:08AM +0100, Jiri Olsa wrote:
> On Mon, Nov 25, 2019 at 11:14:45PM +0800, Changbin Du wrote:
> > This patch adds support for multiple debug options separated by ',' and
> > non-int values.
> > 	--debug verbose=2,stderr
> > 
> > Signed-off-by: Changbin Du <changbin.du@gmail.com>
> > ---
> >  tools/perf/Documentation/perf.txt | 13 +++--
> >  tools/perf/util/debug.c           | 89 ++++++++++++++++---------------
> >  2 files changed, 53 insertions(+), 49 deletions(-)
> > 
> > diff --git a/tools/perf/Documentation/perf.txt b/tools/perf/Documentation/perf.txt
> > index 3f37ded13f8c..fd8d790f68a7 100644
> > --- a/tools/perf/Documentation/perf.txt
> > +++ b/tools/perf/Documentation/perf.txt
> > @@ -19,13 +19,12 @@ OPTIONS
> >  	  --debug verbose=2 # sets verbose = 2
> >  
> >  	List of debug variables allowed to set:
> > -	  verbose          - general debug messages
> > -	  ordered-events   - ordered events object debug messages
> > -	  data-convert     - data convert command debug messages
> > -	  stderr           - write debug output (option -v) to stderr
> > -	                     in browser mode
> > -	  perf-event-open  - Print perf_event_open() arguments and
> > -			     return value
> > +	  verbose=level		- general debug messages
> > +	  ordered-events=level	- ordered events object debug messages
> > +	  data-convert=level	- data convert command debug messages
> > +	  stderr		- write debug output (option -v) to stderr
> > +	  perf-event-open	- Print perf_event_open() arguments and
> > +	                          return value in browser mode
> 
> it's just the list and the doc says user can use values
> there, so no need for the '=level' there
> 
> also we allow this:
>   perf --debug stderr=9 record ls
> 
> so I thinks we should keep it general in documentation,
> eventhough it will always mean just stderr=true for any
> value
>
I changed them as below. For stderr and perf_event_open, the value is ignored
even it is given.

--debug::
	Setup debug variable (see list below). The range of 'level' value
	is (0, 10). Use like:
	  --debug verbose   # sets verbose = 1
	  --debug verbose=2,file=~/perf.log
	                    # sets verbose = 2 and save log to file

	List of debug variables allowed to set:
	  verbose[=level]	- general debug messages
	  ordered-events[=level]- ordered events object debug messages
	  data-convert[=level]	- data convert command debug messages
	  stderr		- write debug output (option -v) to stderr
	                          in browser mode
	  perf-event-open	- Print perf_event_open() arguments and
	                          return value

> jirka
> 

-- 
Cheers,
Changbin Du

[PATCH v6 2/2] perf: add support for logging debug messages to file

[Changbin Du]

When in TUI mode, it is impossible to show all the debug messages to
console. This make it hard to debug perf issues using debug messages.
This patch adds support for logging debug messages to file to resolve
this problem.

The usage is:
perf -debug verbose=2,file=~/perf.log COMMAND

Signed-off-by: Changbin Du <changbin.du@gmail.com>

---
v5: doc default log path.
v4: fix another segfault.
v3: fix a segfault issue.
---
 tools/perf/Documentation/perf.txt | 15 +++++++----
 tools/perf/util/debug.c           | 44 ++++++++++++++++++++++++++++---
 2 files changed, 50 insertions(+), 9 deletions(-)

diff --git a/tools/perf/Documentation/perf.txt b/tools/perf/Documentation/perf.txt
index fd8d790f68a7..a47933b53fbe 100644
--- a/tools/perf/Documentation/perf.txt
+++ b/tools/perf/Documentation/perf.txt
@@ -16,15 +16,20 @@ OPTIONS
 	Setup debug variable (see list below) in value
 	range (0, 10). Use like:
 	  --debug verbose   # sets verbose = 1
-	  --debug verbose=2 # sets verbose = 2
+	  --debug verbose=2,file=~/perf.log
+	                    # sets verbose = 2 and save log to file
 
 	List of debug variables allowed to set:
-	  verbose=level		- general debug messages
-	  ordered-events=level	- ordered events object debug messages
-	  data-convert=level	- data convert command debug messages
-	  stderr		- write debug output (option -v) to stderr
+	  verbose=level         - general debug messages
+	  ordered-events=level  - ordered events object debug messages
+	  data-convert=level    - data convert command debug messages
+	  stderr                - write debug output (option -v) to stderr
+	                          in browser mode
 	  perf-event-open	- Print perf_event_open() arguments and
 	                          return value in browser mode
+	  file[=path]           - write debug output to log file, default
+	                          'perf.log' (stderr and file options are
+	                          exclusive)
 
 --buildid-dir::
 	Setup buildid cache directory. It has higher priority than
diff --git a/tools/perf/util/debug.c b/tools/perf/util/debug.c
index 929da46ece92..21bc889976bc 100644
--- a/tools/perf/util/debug.c
+++ b/tools/perf/util/debug.c
@@ -6,6 +6,7 @@
 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <errno.h>
 #include <sys/wait.h>
 #include <api/debug.h>
 #include <linux/kernel.h>
@@ -27,7 +28,7 @@ int verbose;
 int debug_peo_args;
 bool dump_trace = false, quiet = false;
 int debug_ordered_events;
-static bool redirect_to_stderr;
+static FILE *log_file;
 int debug_data_convert;
 
 int veprintf(int level, int var, const char *fmt, va_list args)
@@ -35,8 +36,10 @@ int veprintf(int level, int var, const char *fmt, va_list args)
 	int ret = 0;
 
 	if (var >= level) {
-		if (use_browser >= 1 && !redirect_to_stderr)
+		if (use_browser >= 1 && !log_file)
 			ui_helpline__vshow(fmt, args);
+		else if (log_file)
+			ret = vfprintf(log_file, fmt, args);
 		else
 			ret = vfprintf(stderr, fmt, args);
 	}
@@ -198,6 +201,24 @@ static int str2loglevel(const char *vstr)
 	return v;
 }
 
+static void flush_log(void)
+{
+	if (log_file)
+		fflush(log_file);
+}
+
+static void set_log_output(FILE *f)
+{
+	if (f == log_file)
+		return;
+
+	if (log_file && log_file != stderr)
+		fclose(log_file);
+
+	log_file = f;
+	atexit(flush_log);
+}
+
 int perf_debug_option(const char *str)
 {
 	char *sep, *vstr;
@@ -219,10 +240,25 @@ int perf_debug_option(const char *str)
 		else if (!strcmp(opt, "data-convert"))
 			debug_data_convert = str2loglevel(vstr);
 		else if (!strcmp(opt, "stderr"))
-			redirect_to_stderr = true;
+			set_log_output(stderr);
 		else if (!strcmp(opt, "perf-event-open"))
 			debug_peo_args = true;
-		else {
+		else if (!strcmp(opt, "file")) {
+			FILE *f;
+
+			if (!vstr)
+				vstr = (char *)"perf.log";
+
+			f = fopen(vstr, "a");
+			if (!f) {
+				pr_err("Can not create log file: %s\n",
+				       strerror(errno));
+				free(dstr);
+				return -1;
+			}
+			fprintf(f, "\n===========perf log===========\n");
+			set_log_output(f);
+		} else {
 			fprintf(stderr, "unkown debug option '%s'\n", opt);
 			free(dstr);
 			return -1;
-- 
2.20.1

Re: [PATCH v6 2/2] perf: add support for logging debug messages to file

[Jiri Olsa]

On Mon, Nov 25, 2019 at 11:14:46PM +0800, Changbin Du wrote:
> When in TUI mode, it is impossible to show all the debug messages to
> console. This make it hard to debug perf issues using debug messages.
> This patch adds support for logging debug messages to file to resolve
> this problem.
> 
> The usage is:
> perf -debug verbose=2,file=~/perf.log COMMAND
> 
> Signed-off-by: Changbin Du <changbin.du@gmail.com>
> 
> ---
> v5: doc default log path.
> v4: fix another segfault.
> v3: fix a segfault issue.
> ---
>  tools/perf/Documentation/perf.txt | 15 +++++++----
>  tools/perf/util/debug.c           | 44 ++++++++++++++++++++++++++++---
>  2 files changed, 50 insertions(+), 9 deletions(-)
> 
> diff --git a/tools/perf/Documentation/perf.txt b/tools/perf/Documentation/perf.txt
> index fd8d790f68a7..a47933b53fbe 100644
> --- a/tools/perf/Documentation/perf.txt
> +++ b/tools/perf/Documentation/perf.txt
> @@ -16,15 +16,20 @@ OPTIONS
>  	Setup debug variable (see list below) in value
>  	range (0, 10). Use like:
>  	  --debug verbose   # sets verbose = 1
> -	  --debug verbose=2 # sets verbose = 2
> +	  --debug verbose=2,file=~/perf.log
> +	                    # sets verbose = 2 and save log to file
>  
>  	List of debug variables allowed to set:
> -	  verbose=level		- general debug messages
> -	  ordered-events=level	- ordered events object debug messages
> -	  data-convert=level	- data convert command debug messages
> -	  stderr		- write debug output (option -v) to stderr
> +	  verbose=level         - general debug messages
> +	  ordered-events=level  - ordered events object debug messages
> +	  data-convert=level    - data convert command debug messages
> +	  stderr                - write debug output (option -v) to stderr
> +	                          in browser mode

hum, why is this changed in this patch?

jirka

>  	  perf-event-open	- Print perf_event_open() arguments and
>  	                          return value in browser mode
> +	  file[=path]           - write debug output to log file, default
> +	                          'perf.log' (stderr and file options are
> +	                          exclusive)
>  
>  --buildid-dir::
>  	Setup buildid cache directory. It has higher priority than
> diff --git a/tools/perf/util/debug.c b/tools/perf/util/debug.c
> index 929da46ece92..21bc889976bc 100644
> --- a/tools/perf/util/debug.c
> +++ b/tools/perf/util/debug.c
> @@ -6,6 +6,7 @@
>  #include <stdarg.h>
>  #include <stdio.h>
>  #include <stdlib.h>
> +#include <errno.h>
>  #include <sys/wait.h>
>  #include <api/debug.h>
>  #include <linux/kernel.h>
> @@ -27,7 +28,7 @@ int verbose;
>  int debug_peo_args;
>  bool dump_trace = false, quiet = false;
>  int debug_ordered_events;
> -static bool redirect_to_stderr;
> +static FILE *log_file;
>  int debug_data_convert;
>  
>  int veprintf(int level, int var, const char *fmt, va_list args)
> @@ -35,8 +36,10 @@ int veprintf(int level, int var, const char *fmt, va_list args)
>  	int ret = 0;
>  
>  	if (var >= level) {
> -		if (use_browser >= 1 && !redirect_to_stderr)
> +		if (use_browser >= 1 && !log_file)
>  			ui_helpline__vshow(fmt, args);
> +		else if (log_file)
> +			ret = vfprintf(log_file, fmt, args);
>  		else
>  			ret = vfprintf(stderr, fmt, args);
>  	}
> @@ -198,6 +201,24 @@ static int str2loglevel(const char *vstr)
>  	return v;
>  }
>  
> +static void flush_log(void)
> +{
> +	if (log_file)
> +		fflush(log_file);
> +}
> +
> +static void set_log_output(FILE *f)
> +{
> +	if (f == log_file)
> +		return;
> +
> +	if (log_file && log_file != stderr)
> +		fclose(log_file);
> +
> +	log_file = f;
> +	atexit(flush_log);
> +}
> +
>  int perf_debug_option(const char *str)
>  {
>  	char *sep, *vstr;
> @@ -219,10 +240,25 @@ int perf_debug_option(const char *str)
>  		else if (!strcmp(opt, "data-convert"))
>  			debug_data_convert = str2loglevel(vstr);
>  		else if (!strcmp(opt, "stderr"))
> -			redirect_to_stderr = true;
> +			set_log_output(stderr);
>  		else if (!strcmp(opt, "perf-event-open"))
>  			debug_peo_args = true;
> -		else {
> +		else if (!strcmp(opt, "file")) {
> +			FILE *f;
> +
> +			if (!vstr)
> +				vstr = (char *)"perf.log";
> +
> +			f = fopen(vstr, "a");
> +			if (!f) {
> +				pr_err("Can not create log file: %s\n",
> +				       strerror(errno));
> +				free(dstr);
> +				return -1;
> +			}
> +			fprintf(f, "\n===========perf log===========\n");
> +			set_log_output(f);
> +		} else {
>  			fprintf(stderr, "unkown debug option '%s'\n", opt);
>  			free(dstr);
>  			return -1;
> -- 
> 2.20.1
>