* [PATCH v3 lttng-ust 1/2] Introduce vtracef
@ 2020-02-24 17:34 Maxime Roussin-Belanger
2020-02-24 17:34 ` [PATCH v3 lttng-ust 2/2] Introduce vtracelog Maxime Roussin-Belanger
` (3 more replies)
0 siblings, 4 replies; 7+ messages in thread
From: Maxime Roussin-Belanger @ 2020-02-24 17:34 UTC (permalink / raw)
To: lttng-dev
vtracef accepts a va_list argument to simplify
tracing functions which use a va_list
Here's an example from wpa_supplicant that I wanted to
trace:
void wpa_debug(int level, const char* fmt, ...)
{
va_list ap;
va_start(ap, fmt);
...
// The call I want to easily trace with vtracef
vprintf(fmt, ap);
...
va_end(ap);
}
wpa_debug is used a fair amount and it would be annoying to
replace all the wpa_debug calls with tracef.
With vtracef, it simplifies the find and replace effort by
only changing it at one place.
Signed-off-by: Maxime Roussin-Belanger <maxime.roussinbelanger@gmail.com>
---
Changes in v3:
* Fix coding style patch
doc/examples/demo-tracef/Makefile | 14 +++++-
doc/examples/demo-tracef/demo-vtracef.c | 59 +++++++++++++++++++++++++
doc/man/tracef-tracelog-limitations.txt | 3 ++
doc/man/tracef.3.txt | 11 ++---
include/lttng/tracef.h | 8 ++++
liblttng-ust/tracef.c | 18 +++++---
6 files changed, 100 insertions(+), 13 deletions(-)
create mode 100644 doc/examples/demo-tracef/demo-vtracef.c
diff --git a/doc/examples/demo-tracef/Makefile b/doc/examples/demo-tracef/Makefile
index ee207843..809aac19 100644
--- a/doc/examples/demo-tracef/Makefile
+++ b/doc/examples/demo-tracef/Makefile
@@ -20,18 +20,28 @@ LIBS = -ldl -llttng-ust # On Linux
LOCAL_CPPFLAGS += -I.
AM_V_P := :
-all: demo-tracef
+all: demo-tracef demo-vtracef
demo-tracef.o: demo-tracef.c
@if $(AM_V_P); then set -x; else echo " CC $@"; fi; \
$(CC) $(CPPFLAGS) $(LOCAL_CPPFLAGS) $(AM_CFLAGS) $(AM_CPPFLAGS) \
$(CFLAGS) -c -o $@ $<
demo-tracef: demo-tracef.o
@if $(AM_V_P); then set -x; else echo " CCLD $@"; fi; \
$(CC) $(LDFLAGS) $(AM_CFLAGS) $(AM_LDFLAGS) $(CFLAGS) \
-o $@ $< $(LIBS)
+demo-vtracef.o: demo-vtracef.c
+ @if $(AM_V_P); then set -x; else echo " CC $@"; fi; \
+ $(CC) $(CPPFLAGS) $(LOCAL_CPPFLAGS) $(AM_CFLAGS) $(AM_CPPFLAGS) \
+ $(CFLAGS) -c -o $@ $<
+
+demo-vtracef: demo-vtracef.o
+ @if $(AM_V_P); then set -x; else echo " CCLD $@"; fi; \
+ $(CC) $(LDFLAGS) $(AM_CFLAGS) $(AM_LDFLAGS) $(CFLAGS) \
+ -o $@ $< $(LIBS)
+
.PHONY: clean
clean:
- rm -f *.o *.a demo-tracef
+ rm -f *.o *.a demo-tracef demo-vtracef
diff --git a/doc/examples/demo-tracef/demo-vtracef.c b/doc/examples/demo-tracef/demo-vtracef.c
new file mode 100644
index 00000000..224e9292
--- /dev/null
+++ b/doc/examples/demo-tracef/demo-vtracef.c
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2020 Maxime Roussin-Belanger <maxime.roussinbelanger@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; version 2.1 of
+ * the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdarg.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include <lttng/tracef.h>
+
+
+void print_debug(const char* msg, ...)
+{
+ va_list ap;
+ va_start(ap, msg);
+
+ vtracef(msg, ap);
+
+ va_end(ap);
+}
+
+int main(int argc, char **argv)
+{
+ int i;
+ int delay = 0;
+ const char *str = "mystring test";
+ long l = 0x42;
+
+ if (argc == 2)
+ delay = atoi(argv[1]);
+
+ fprintf(stderr, "Demo program starting.\n");
+
+ sleep(delay);
+
+ fprintf(stderr, "Tracing... ");
+
+ for (i = 0; i < 5; i++) {
+ print_debug("This is a \"%s\" formatted %d event %lx", str, i, l);
+ }
+
+ fprintf(stderr, " done.\n");
+ return 0;
+}
diff --git a/doc/man/tracef-tracelog-limitations.txt b/doc/man/tracef-tracelog-limitations.txt
index a9491903..ad4130dd 100644
--- a/doc/man/tracef-tracelog-limitations.txt
+++ b/doc/man/tracef-tracelog-limitations.txt
@@ -21,4 +21,7 @@ Thus, +{macro-name}()+ is useful for quick prototyping and debugging, but
should not be considered for any permanent/serious application
instrumentation.
++v{macro-name}()+ does not have a `STAP_PROBEV()` call, because `STAP_PROBEV()`
+does not support `va_list`. If you need it, you should emit this call yourself.
+
See man:lttng-ust(3) to learn more about custom tracepoint providers.
diff --git a/doc/man/tracef.3.txt b/doc/man/tracef.3.txt
index 1068afad..2894ca45 100644
--- a/doc/man/tracef.3.txt
+++ b/doc/man/tracef.3.txt
@@ -5,43 +5,44 @@ tracef(3)
NAME
----
-tracef - LTTng-UST printf(3)-like interface
+tracef, vtracef - LTTng-UST printf(3)-like interface
SYNOPSIS
--------
[verse]
*#include <lttng/tracef.h>*
[verse]
#define *tracef*('fmt', ...)
+#define *vtracef*('fmt', 'va_list' ap)
Link with `-llttng-ust`.
DESCRIPTION
-----------
The LTTng-UST `tracef()` API allows you to trace your application with
the help of a simple man:printf(3)-like macro. The 'fmt' argument is
passed directly to the 'fmt' parameter of man:vasprintf(3), as well as
the optional parameters following 'fmt'.
-To use `tracef()`, include `<lttng/tracef.h>` where you need it, and
-link your application with `liblttng-ust`. See the <<example,EXAMPLE>>
+To use `tracef()` or `vtracef()`, include `<lttng/tracef.h>` where you need it,
+and link your application with `liblttng-ust`. See the <<example,EXAMPLE>>
section below for a complete usage example.
-Once your application is instrumented with `tracef()` calls and
+Once your application is instrumented with `tracef()` or `vtracef()` calls and
ready to run, use man:lttng-enable-event(1) to enable the
`lttng_ust_tracef:*` event.
The `tracef()` events contain a single field, named `msg`, which is the
formatted string output.
If you need to attach a specific log level to a `tracef()` call, use
man:tracelog(3) instead.
See also the <<limitations,LIMITATIONS>> section below for important
-limitations to consider when using `tracef()`.
+limitations to consider when using `tracef()` or `vtracef()`.
[[example]]
diff --git a/include/lttng/tracef.h b/include/lttng/tracef.h
index 0c59c9ae..854ccdce 100644
--- a/include/lttng/tracef.h
+++ b/include/lttng/tracef.h
@@ -32,13 +32,21 @@ extern "C" {
extern
void _lttng_ust_tracef(const char *fmt, ...);
+extern
+void _lttng_ust_vtracef(const char *fmt, va_list ap);
+
#define tracef(fmt, ...) \
do { \
LTTNG_STAP_PROBEV(tracepoint_lttng_ust_tracef, event, ## __VA_ARGS__); \
if (caa_unlikely(__tracepoint_lttng_ust_tracef___event.state)) \
_lttng_ust_tracef(fmt, ## __VA_ARGS__); \
} while (0)
+#define vtracef(fmt, ap) \
+ do { \
+ if (caa_unlikely(__tracepoint_lttng_ust_tracef___event.state)) \
+ _lttng_ust_vtracef(fmt, ap); \
+ } while (0)
#ifdef __cplusplus
}
#endif
diff --git a/liblttng-ust/tracef.c b/liblttng-ust/tracef.c
index ea98e43e..1311f0d5 100644
--- a/liblttng-ust/tracef.c
+++ b/liblttng-ust/tracef.c
@@ -29,20 +29,26 @@
#define TRACEPOINT_DEFINE
#include "lttng-ust-tracef-provider.h"
-void _lttng_ust_tracef(const char *fmt, ...)
+void _lttng_ust_vtracef(const char *fmt, va_list ap)
{
- va_list ap;
char *msg;
- int len;
-
- va_start(ap, fmt);
- len = vasprintf(&msg, fmt, ap);
+ const int len = vasprintf(&msg, fmt, ap);
/* len does not include the final \0 */
if (len < 0)
goto end;
__tracepoint_cb_lttng_ust_tracef___event(msg, len,
LTTNG_UST_CALLER_IP());
free(msg);
end:
+ return;
+}
+
+void _lttng_ust_tracef(const char *fmt, ...)
+{
+ va_list ap;
+
+ va_start(ap, fmt);
+ _lttng_ust_vtracef(fmt, ap);
+
va_end(ap);
}
--
2.20.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH v3 lttng-ust 2/2] Introduce vtracelog
2020-02-24 17:34 [PATCH v3 lttng-ust 1/2] Introduce vtracef Maxime Roussin-Belanger
@ 2020-02-24 17:34 ` Maxime Roussin-Belanger
2020-02-26 21:15 ` Mathieu Desnoyers
2020-02-26 21:07 ` [PATCH v3 lttng-ust 1/2] Introduce vtracef Mathieu Desnoyers
` (2 subsequent siblings)
3 siblings, 1 reply; 7+ messages in thread
From: Maxime Roussin-Belanger @ 2020-02-24 17:34 UTC (permalink / raw)
To: lttng-dev
vtracelog works the same as vtracef, but takes a log level
as a parameter and has the same limitations.
Signed-off-by: Maxime Roussin-Belanger <maxime.roussinbelanger@gmail.com>
---
Changes in v3:
* Add this patch
doc/examples/demo-tracelog/Makefile | 14 +++++-
doc/examples/demo-tracelog/demo-vtracelog.c | 53 +++++++++++++++++++++
doc/man/tracelog.3.txt | 9 ++--
include/lttng/tracelog.h | 7 +++
liblttng-ust/tracelog.c | 24 ++++++----
5 files changed, 93 insertions(+), 14 deletions(-)
create mode 100644 doc/examples/demo-tracelog/demo-vtracelog.c
diff --git a/doc/examples/demo-tracelog/Makefile b/doc/examples/demo-tracelog/Makefile
index 0d9a20aa..623979d3 100644
--- a/doc/examples/demo-tracelog/Makefile
+++ b/doc/examples/demo-tracelog/Makefile
@@ -20,18 +20,28 @@ LIBS = -ldl -llttng-ust # On Linux
LOCAL_CPPFLAGS += -I.
AM_V_P := :
-all: demo-tracelog
+all: demo-tracelog demo-vtracelog
demo-tracelog.o: demo-tracelog.c
@if $(AM_V_P); then set -x; else echo " CC $@"; fi; \
$(CC) $(CPPFLAGS) $(LOCAL_CPPFLAGS) $(AM_CFLAGS) $(AM_CPPFLAGS) \
$(CFLAGS) -c -o $@ $<
demo-tracelog: demo-tracelog.o
@if $(AM_V_P); then set -x; else echo " CCLD $@"; fi; \
$(CC) $(LDFLAGS) $(AM_CFLAGS) $(AM_LDFLAGS) $(CFLAGS) \
-o $@ $< $(LIBS)
+demo-vtracelog.o: demo-vtracelog.c
+ @if $(AM_V_P); then set -x; else echo " CC $@"; fi; \
+ $(CC) $(CPPFLAGS) $(LOCAL_CPPFLAGS) $(AM_CFLAGS) $(AM_CPPFLAGS) \
+ $(CFLAGS) -c -o $@ $<
+
+demo-vtracelog: demo-vtracelog.o
+ @if $(AM_V_P); then set -x; else echo " CCLD $@"; fi; \
+ $(CC) $(LDFLAGS) $(AM_CFLAGS) $(AM_LDFLAGS) $(CFLAGS) \
+ -o $@ $< $(LIBS)
+
.PHONY: clean
clean:
- rm -f *.o *.a demo-tracelog
+ rm -f *.o *.a demo-tracelog demo-vtracelog
diff --git a/doc/examples/demo-tracelog/demo-vtracelog.c b/doc/examples/demo-tracelog/demo-vtracelog.c
new file mode 100644
index 00000000..5e7f3884
--- /dev/null
+++ b/doc/examples/demo-tracelog/demo-vtracelog.c
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2020 Maxime Roussin-Belanger <maxime.roussinbelanger@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; version 2.1 of
+ * the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include <lttng/tracelog.h>
+
+void print_debug(const char* msg, ...)
+{
+ va_list ap;
+ va_start(ap, msg);
+
+ vtracelog(TRACE_DEBUG, msg, ap);
+
+ va_end(ap);
+}
+
+int main(int argc, char **argv)
+{
+ int i;
+ int delay = 0;
+
+ if (argc == 2)
+ delay = atoi(argv[1]);
+
+ fprintf(stderr, "Demo program starting.\n");
+
+ sleep(delay);
+
+ fprintf(stderr, "Tracing... ");
+ for (i = 0; i < 5; i++) {
+ print_debug("Error condition %d", i);
+ }
+ fprintf(stderr, " done.\n");
+ return 0;
+}
diff --git a/doc/man/tracelog.3.txt b/doc/man/tracelog.3.txt
index 1281ce7c..5cf1953a 100644
--- a/doc/man/tracelog.3.txt
+++ b/doc/man/tracelog.3.txt
@@ -15,6 +15,7 @@ SYNOPSIS
[verse]
#define *tracelog*('level', 'fmt', ...)
+#define *vtracelog*('level', 'fmt', 'va_list' ap)
Link with `-llttng-ust`.
@@ -34,9 +35,9 @@ The available values for the 'level' parameter are:
include::log-levels.txt[]
-To use `tracelog()`, include `<lttng/tracelog.h>` where you need it, and
-link your application with `liblttng-ust`. See the <<example,EXAMPLE>>
-section below for a complete usage example.
+To use `tracelog()` or `vtracelog()`, include `<lttng/tracelog.h>` where you
+need it, and link your application with `liblttng-ust`.
+See the <<example,EXAMPLE>> section below for a complete usage example.
Once your application is instrumented with `tracelog()` calls and
ready to run, use man:lttng-enable-event(1) to enable the
@@ -67,7 +68,7 @@ If you do not need to attach a specific log level to a `tracelog()`
call, use man:tracef(3) instead.
See also the <<limitations,LIMITATIONS>> section below for important
-limitations to consider when using `tracelog()`.
+limitations to consider when using `tracelog()` or `vtracelog()`.
[[example]]
diff --git a/include/lttng/tracelog.h b/include/lttng/tracelog.h
index 4309d12e..7aa86809 100644
--- a/include/lttng/tracelog.h
+++ b/include/lttng/tracelog.h
@@ -59,6 +59,13 @@ TP_TRACELOG_CB_TEMPLATE(TRACE_DEBUG);
fmt, ## __VA_ARGS__); \
} while (0)
+#define vtracelog(level, fmt, ap) \
+ do { \
+ if (caa_unlikely(__tracepoint_lttng_ust_tracelog___##level.state)) \
+ _lttng_ust_tracelog_##level(__FILE__, __LINE__, __func__, \
+ fmt, ap); \
+ } while (0)
+
#ifdef __cplusplus
}
#endif
diff --git a/liblttng-ust/tracelog.c b/liblttng-ust/tracelog.c
index 65fc87ed..17546605 100644
--- a/liblttng-ust/tracelog.c
+++ b/liblttng-ust/tracelog.c
@@ -29,27 +29,35 @@
#define TRACEPOINT_DEFINE
#include "lttng-ust-tracelog-provider.h"
+
#define TRACELOG_CB(level) \
- void _lttng_ust_tracelog_##level(const char *file, \
+ void _lttng_ust_vtracelog_##level(const char *file, \
int line, const char *func, \
- const char *fmt, ...) \
+ const char *fmt, va_list ap) \
{ \
- va_list ap; \
- char *msg; \
- int len; \
+ char *msg; \
+ const int len = vasprintf(&msg, fmt, ap); \
\
- va_start(ap, fmt); \
- len = vasprintf(&msg, fmt, ap); \
/* len does not include the final \0 */ \
if (len < 0) \
goto end; \
__tracepoint_cb_lttng_ust_tracelog___##level(file, \
line, func, msg, len, \
LTTNG_UST_CALLER_IP()); \
free(msg); \
end: \
+ return; \
+ } \
+ \
+ void _lttng_ust_tracelog_##level(const char *file, \
+ int line, const char *func, \
+ const char *fmt, ...) \
+ { \
+ va_list ap; \
+ va_start(ap, fmt); \
+ _lttng_ust_vtracelog_##level(file, line, func, fmt, ap); \
va_end(ap); \
- }
+ } \
TRACELOG_CB(TRACE_EMERG)
TRACELOG_CB(TRACE_ALERT)
--
2.20.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH v3 lttng-ust 2/2] Introduce vtracelog
2020-02-24 17:34 ` [PATCH v3 lttng-ust 2/2] Introduce vtracelog Maxime Roussin-Belanger
@ 2020-02-26 21:15 ` Mathieu Desnoyers
0 siblings, 0 replies; 7+ messages in thread
From: Mathieu Desnoyers @ 2020-02-26 21:15 UTC (permalink / raw)
To: Maxime Roussin-Belanger; +Cc: lttng-dev
----- On Feb 24, 2020, at 12:34 PM, Maxime Roussin-Belanger maxime.roussinbelanger@gmail.com wrote:
[...]
> +int main(int argc, char **argv)
> +{
> + int i;
> + int delay = 0;
> +
> + if (argc == 2)
Check for argc > 2 as well here.
[...]
> diff --git a/liblttng-ust/tracelog.c b/liblttng-ust/tracelog.c
> index 65fc87ed..17546605 100644
> --- a/liblttng-ust/tracelog.c
> +++ b/liblttng-ust/tracelog.c
> @@ -29,27 +29,35 @@
> #define TRACEPOINT_DEFINE
> #include "lttng-ust-tracelog-provider.h"
>
> +
> #define TRACELOG_CB(level) \
> - void _lttng_ust_tracelog_##level(const char *file, \
> + void _lttng_ust_vtracelog_##level(const char *file, \
> int line, const char *func, \
> - const char *fmt, ...) \
> + const char *fmt, va_list ap) \
> { \
> - va_list ap; \
> - char *msg; \
> - int len; \
> + char *msg; \
> + const int len = vasprintf(&msg, fmt, ap); \
> \
> - va_start(ap, fmt); \
> - len = vasprintf(&msg, fmt, ap); \
> /* len does not include the final \0 */ \
> if (len < 0) \
> goto end; \
> __tracepoint_cb_lttng_ust_tracelog___##level(file, \
> line, func, msg, len, \
> LTTNG_UST_CALLER_IP()); \
Same as tracef: LTTNG_UST_CALLER_IP() does not have the expected behavior
for _lttng_ust_tracelog_##level anymore. And I would want to ensure we don't
add an additional call indirection in the generated text.
> free(msg); \
> end: \
> + return; \
> + } \
> + \
> + void _lttng_ust_tracelog_##level(const char *file, \
> + int line, const char *func, \
> + const char *fmt, ...) \
> + { \
> + va_list ap; \
> + va_start(ap, fmt); \
> + _lttng_ust_vtracelog_##level(file, line, func, fmt, ap); \
> va_end(ap); \
> - }
> + } \
I suspect you will want to remove the "\" on the last line here.
Thanks,
Mathieu
>
> TRACELOG_CB(TRACE_EMERG)
> TRACELOG_CB(TRACE_ALERT)
> --
> 2.20.1
>
> _______________________________________________
> lttng-dev mailing list
> lttng-dev@lists.lttng.org
> https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v3 lttng-ust 1/2] Introduce vtracef
2020-02-24 17:34 [PATCH v3 lttng-ust 1/2] Introduce vtracef Maxime Roussin-Belanger
2020-02-24 17:34 ` [PATCH v3 lttng-ust 2/2] Introduce vtracelog Maxime Roussin-Belanger
@ 2020-02-26 21:07 ` Mathieu Desnoyers
2020-02-26 21:10 ` Mathieu Desnoyers
2020-02-26 21:14 ` Mathieu Desnoyers
3 siblings, 0 replies; 7+ messages in thread
From: Mathieu Desnoyers @ 2020-02-26 21:07 UTC (permalink / raw)
To: Maxime Roussin-Belanger; +Cc: lttng-dev
----- On Feb 24, 2020, at 12:34 PM, Maxime Roussin-Belanger maxime.roussinbelanger@gmail.com wrote:
[...]
> diff --git a/liblttng-ust/tracef.c b/liblttng-ust/tracef.c
> index ea98e43e..1311f0d5 100644
> --- a/liblttng-ust/tracef.c
> +++ b/liblttng-ust/tracef.c
> @@ -29,20 +29,26 @@
> #define TRACEPOINT_DEFINE
> #include "lttng-ust-tracef-provider.h"
>
> -void _lttng_ust_tracef(const char *fmt, ...)
> +void _lttng_ust_vtracef(const char *fmt, va_list ap)
> {
> - va_list ap;
> char *msg;
> - int len;
> -
> - va_start(ap, fmt);
> - len = vasprintf(&msg, fmt, ap);
> + const int len = vasprintf(&msg, fmt, ap);
> /* len does not include the final \0 */
> if (len < 0)
> goto end;
> __tracepoint_cb_lttng_ust_tracef___event(msg, len,
> LTTNG_UST_CALLER_IP());
> free(msg);
> end:
> + return;
> +}
> +
> +void _lttng_ust_tracef(const char *fmt, ...)
> +{
> + va_list ap;
> +
> + va_start(ap, fmt);
> + _lttng_ust_vtracef(fmt, ap);
> +
> va_end(ap);
> }
Can you check the result of the generated binary (compiled with -O2) to see if
there is an additional call added for _lttng_ust_trace() compared to the prior
generated code ? I would hate to add an extra call indirection there.
Thanks,
Mathieu
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v3 lttng-ust 1/2] Introduce vtracef
2020-02-24 17:34 [PATCH v3 lttng-ust 1/2] Introduce vtracef Maxime Roussin-Belanger
2020-02-24 17:34 ` [PATCH v3 lttng-ust 2/2] Introduce vtracelog Maxime Roussin-Belanger
2020-02-26 21:07 ` [PATCH v3 lttng-ust 1/2] Introduce vtracef Mathieu Desnoyers
@ 2020-02-26 21:10 ` Mathieu Desnoyers
2020-02-26 21:14 ` Mathieu Desnoyers
3 siblings, 0 replies; 7+ messages in thread
From: Mathieu Desnoyers @ 2020-02-26 21:10 UTC (permalink / raw)
To: Maxime Roussin-Belanger; +Cc: lttng-dev
----- On Feb 24, 2020, at 12:34 PM, Maxime Roussin-Belanger maxime.roussinbelanger@gmail.com wrote:
> diff --git a/doc/examples/demo-tracef/demo-vtracef.c
> b/doc/examples/demo-tracef/demo-vtracef.c
> new file mode 100644
> index 00000000..224e9292
> --- /dev/null
> +++ b/doc/examples/demo-tracef/demo-vtracef.c
> @@ -0,0 +1,59 @@
> +/*
> + * Copyright (C) 2020 Maxime Roussin-Belanger
> <maxime.roussinbelanger@gmail.com>
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; version 2.1 of
> + * the License.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
> USA
> + */
> +
> +#include <stdarg.h>
> +#include <stdlib.h>
> +#include <stdio.h>
> +#include <unistd.h>
> +
> +#include <lttng/tracef.h>
> +
> +
Remove one whiteline here.
> +void print_debug(const char* msg, ...)
> +{
> + va_list ap;
> + va_start(ap, msg);
> +
> + vtracef(msg, ap);
> +
> + va_end(ap);
> +}
> +
> +int main(int argc, char **argv)
> +{
> + int i;
> + int delay = 0;
> + const char *str = "mystring test";
> + long l = 0x42;
> +
> + if (argc == 2)
Should handle cases where argc > 2 as well.
> + delay = atoi(argv[1]);
> +
> + fprintf(stderr, "Demo program starting.\n");
> +
> + sleep(delay);
> +
> + fprintf(stderr, "Tracing... ");
> +
> + for (i = 0; i < 5; i++) {
> + print_debug("This is a \"%s\" formatted %d event %lx", str, i, l);
> + }
> +
> + fprintf(stderr, " done.\n");
> + return 0;
> +}
Thanks,
Mathieu
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v3 lttng-ust 1/2] Introduce vtracef
2020-02-24 17:34 [PATCH v3 lttng-ust 1/2] Introduce vtracef Maxime Roussin-Belanger
` (2 preceding siblings ...)
2020-02-26 21:10 ` Mathieu Desnoyers
@ 2020-02-26 21:14 ` Mathieu Desnoyers
2020-03-03 19:10 ` Mathieu Desnoyers
3 siblings, 1 reply; 7+ messages in thread
From: Mathieu Desnoyers @ 2020-02-26 21:14 UTC (permalink / raw)
To: Maxime Roussin-Belanger; +Cc: lttng-dev
----- On Feb 24, 2020, at 12:34 PM, Maxime Roussin-Belanger maxime.roussinbelanger@gmail.com wrote:
[...]
> diff --git a/liblttng-ust/tracef.c b/liblttng-ust/tracef.c
> index ea98e43e..1311f0d5 100644
> --- a/liblttng-ust/tracef.c
> +++ b/liblttng-ust/tracef.c
> @@ -29,20 +29,26 @@
> #define TRACEPOINT_DEFINE
> #include "lttng-ust-tracef-provider.h"
>
> -void _lttng_ust_tracef(const char *fmt, ...)
> +void _lttng_ust_vtracef(const char *fmt, va_list ap)
> {
> - va_list ap;
> char *msg;
> - int len;
> -
> - va_start(ap, fmt);
> - len = vasprintf(&msg, fmt, ap);
> + const int len = vasprintf(&msg, fmt, ap);
> /* len does not include the final \0 */
> if (len < 0)
> goto end;
> __tracepoint_cb_lttng_ust_tracef___event(msg, len,
> LTTNG_UST_CALLER_IP());
I don't think LTTNG_UST_CALLER_IP() has the behavior we would expect
for _lttng_ust_tracef() anymore here. We want the callsite in the application
or library which has been instrumented, not an IP within lttng-ust.
Thanks,
Mathieu
> free(msg);
> end:
> + return;
> +}
> +
> +void _lttng_ust_tracef(const char *fmt, ...)
> +{
> + va_list ap;
> +
> + va_start(ap, fmt);
> + _lttng_ust_vtracef(fmt, ap);
> +
> va_end(ap);
> }
> --
> 2.20.1
>
> _______________________________________________
> lttng-dev mailing list
> lttng-dev@lists.lttng.org
> https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v3 lttng-ust 1/2] Introduce vtracef
2020-02-26 21:14 ` Mathieu Desnoyers
@ 2020-03-03 19:10 ` Mathieu Desnoyers
0 siblings, 0 replies; 7+ messages in thread
From: Mathieu Desnoyers @ 2020-03-03 19:10 UTC (permalink / raw)
To: Maxime Roussin-Belanger; +Cc: lttng-dev
----- On Feb 26, 2020, at 4:14 PM, Mathieu Desnoyers mathieu.desnoyers@efficios.com wrote:
> ----- On Feb 24, 2020, at 12:34 PM, Maxime Roussin-Belanger
> maxime.roussinbelanger@gmail.com wrote:
> [...]
>> diff --git a/liblttng-ust/tracef.c b/liblttng-ust/tracef.c
>> index ea98e43e..1311f0d5 100644
>> --- a/liblttng-ust/tracef.c
>> +++ b/liblttng-ust/tracef.c
>> @@ -29,20 +29,26 @@
>> #define TRACEPOINT_DEFINE
>> #include "lttng-ust-tracef-provider.h"
>>
>> -void _lttng_ust_tracef(const char *fmt, ...)
>> +void _lttng_ust_vtracef(const char *fmt, va_list ap)
>> {
>> - va_list ap;
>> char *msg;
>> - int len;
>> -
>> - va_start(ap, fmt);
>> - len = vasprintf(&msg, fmt, ap);
>> + const int len = vasprintf(&msg, fmt, ap);
>> /* len does not include the final \0 */
>> if (len < 0)
>> goto end;
>> __tracepoint_cb_lttng_ust_tracef___event(msg, len,
>> LTTNG_UST_CALLER_IP());
>
> I don't think LTTNG_UST_CALLER_IP() has the behavior we would expect
> for _lttng_ust_tracef() anymore here. We want the callsite in the application
> or library which has been instrumented, not an IP within lttng-ust.
The following should fix both inlining and CALLER_IP() issues:
static inline __attribute__((always_inline))
void __lttng_ust_vtracef(const char *fmt, va_list ap)
{
char *msg;
const int len = vasprintf(&msg, fmt, ap);
/* len does not include the final \0 */
if (len < 0)
goto end;
__tracepoint_cb_lttng_ust_tracef___event(msg, len,
LTTNG_UST_CALLER_IP());
free(msg);
end:
return;
}
void _lttng_ust_vtracef(const char *fmt, va_list ap)
{
__lttng_ust_vtracef(fmt, ap);
}
void _lttng_ust_tracef(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
__lttng_ust_vtracef(fmt, ap);
va_end(ap);
}
Thanks,
Mathieu
>
> Thanks,
>
> Mathieu
>
>> free(msg);
>> end:
>> + return;
>> +}
>> +
>> +void _lttng_ust_tracef(const char *fmt, ...)
>> +{
>> + va_list ap;
>> +
>> + va_start(ap, fmt);
>> + _lttng_ust_vtracef(fmt, ap);
>> +
>> va_end(ap);
>> }
>> --
>> 2.20.1
>>
>> _______________________________________________
>> lttng-dev mailing list
>> lttng-dev@lists.lttng.org
>> https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
>
> --
> Mathieu Desnoyers
> EfficiOS Inc.
> http://www.efficios.com
> _______________________________________________
> lttng-dev mailing list
> lttng-dev@lists.lttng.org
> https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
^ permalink raw reply [flat|nested] 7+ messages in thread
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2020-02-24 17:34 [PATCH v3 lttng-ust 1/2] Introduce vtracef Maxime Roussin-Belanger
2020-02-24 17:34 ` [PATCH v3 lttng-ust 2/2] Introduce vtracelog Maxime Roussin-Belanger
2020-02-26 21:15 ` Mathieu Desnoyers
2020-02-26 21:07 ` [PATCH v3 lttng-ust 1/2] Introduce vtracef Mathieu Desnoyers
2020-02-26 21:10 ` Mathieu Desnoyers
2020-02-26 21:14 ` Mathieu Desnoyers
2020-03-03 19:10 ` Mathieu Desnoyers
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