[Qemu-devel] [PATCH v4 0/5] Fix UST backend for LTTng 2.x

[Qemu-devel] [PATCH v4 0/5] Fix UST backend for LTTng 2.x

[Mohamad Gebai]

Version 4

* Update documentation

Mohamad Gebai (5):
  Fix configure script for LTTng 2.x
  Modified the tracetool framework for LTTng 2.x.
  Adapt Makefiles to the new LTTng ust interface.
  Update documentation for LTTng ust tracing
  Add ust generated files to .gitignore

 .gitignore                               |    2 +
 Makefile                                 |    5 ++
 configure                                |    9 ++--
 docs/tracing.txt                         |   36 +++++++++++++
 scripts/tracetool/backend/events.py      |   44 ++++++++++++++++
 scripts/tracetool/backend/ust.py         |   82 ++++++------------------------
 scripts/tracetool/format/ust_events_c.py |   30 +++++++++++
 scripts/tracetool/format/ust_events_h.py |   57 +++++++++++++++++++++
 trace/Makefile.objs                      |   29 ++++++++++-
 9 files changed, 221 insertions(+), 73 deletions(-)
 create mode 100644 scripts/tracetool/format/ust_events_c.py
 create mode 100644 scripts/tracetool/format/ust_events_h.py

-- 
1.7.10.4

[Qemu-devel] [PATCH v4 1/5] Fix configure script for LTTng 2.x

[Mohamad Gebai]

Signed-off-by: Mohamad Gebai <mohamad.gebai@polymtl.ca>
---
 configure |    9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/configure b/configure
index 23dbaaf..627054c 100755
--- a/configure
+++ b/configure
@@ -3287,15 +3287,14 @@ fi
 # For 'ust' backend, test if ust headers are present
 if test "$trace_backend" = "ust"; then
   cat > $TMPC << EOF
-#include <ust/tracepoint.h>
-#include <ust/marker.h>
+#include <lttng/tracepoint.h>
 int main(void) { return 0; }
 EOF
   if compile_prog "" "" ; then
-    LIBS="-lust -lurcu-bp $LIBS"
-    libs_qga="-lust -lurcu-bp $libs_qga"
+    LIBS="-llttng-ust -lurcu-bp -ldl $LIBS"
+    libs_qga="-llttng-ust -lurcu-bp -ldl $libs_qga"
   else
-    error_exit "Trace backend 'ust' missing libust header files"
+    error_exit "Trace backend 'ust' missing lttng-ust header files"
   fi
 fi
 
-- 
1.7.10.4

Re: [Qemu-devel] [PATCH v4 1/5] Fix configure script for LTTng 2.x

[Stefan Hajnoczi]

On Fri, Oct 18, 2013 at 02:39:49AM -0400, Mohamad Gebai wrote:
> Signed-off-by: Mohamad Gebai <mohamad.gebai@polymtl.ca>
> ---
>  configure |    9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/configure b/configure
> index 23dbaaf..627054c 100755
> --- a/configure
> +++ b/configure
> @@ -3287,15 +3287,14 @@ fi
>  # For 'ust' backend, test if ust headers are present
>  if test "$trace_backend" = "ust"; then
>    cat > $TMPC << EOF
> -#include <ust/tracepoint.h>
> -#include <ust/marker.h>
> +#include <lttng/tracepoint.h>
>  int main(void) { return 0; }
>  EOF
>    if compile_prog "" "" ; then
> -    LIBS="-lust -lurcu-bp $LIBS"
> -    libs_qga="-lust -lurcu-bp $libs_qga"
> +    LIBS="-llttng-ust -lurcu-bp -ldl $LIBS"
> +    libs_qga="-llttng-ust -lurcu-bp -ldl $libs_qga"

Please switch to pkg-config instead of hardcoding particular flags.  I
checked that Fedora and Debian ship the pkg-config file.

Re: [Qemu-devel] [PATCH v4 1/5] Fix configure script for LTTng 2.x

[Mohamad Gebai]

On 13-10-18 10:05 AM, Stefan Hajnoczi wrote:
> On Fri, Oct 18, 2013 at 02:39:49AM -0400, Mohamad Gebai wrote:
>> Signed-off-by: Mohamad Gebai <mohamad.gebai@polymtl.ca>
>> ---
>>   configure |    9 ++++-----
>>   1 file changed, 4 insertions(+), 5 deletions(-)
>>
>> diff --git a/configure b/configure
>> index 23dbaaf..627054c 100755
>> --- a/configure
>> +++ b/configure
>> @@ -3287,15 +3287,14 @@ fi
>>   # For 'ust' backend, test if ust headers are present
>>   if test "$trace_backend" = "ust"; then
>>     cat > $TMPC << EOF
>> -#include <ust/tracepoint.h>
>> -#include <ust/marker.h>
>> +#include <lttng/tracepoint.h>
>>   int main(void) { return 0; }
>>   EOF
>>     if compile_prog "" "" ; then
>> -    LIBS="-lust -lurcu-bp $LIBS"
>> -    libs_qga="-lust -lurcu-bp $libs_qga"
>> +    LIBS="-llttng-ust -lurcu-bp -ldl $LIBS"
>> +    libs_qga="-llttng-ust -lurcu-bp -ldl $libs_qga"
> Please switch to pkg-config instead of hardcoding particular flags.  I
> checked that Fedora and Debian ship the pkg-config file.
Unfortunately, some missing files in the Ubuntu package make it 
impossible to use pkg-config for versions of Ubuntu older than 13.10 
(like Ubuntu 12.04 which is a LTS). Would you be okay with these flags?

Re: [Qemu-devel] [PATCH v4 1/5] Fix configure script for LTTng 2.x

[Alex Bennée]

mohamad.gebai@polymtl.ca writes:

> On 13-10-18 10:05 AM, Stefan Hajnoczi wrote:
<snip>
>> Please switch to pkg-config instead of hardcoding particular flags.  I
>> checked that Fedora and Debian ship the pkg-config file.
> Unfortunately, some missing files in the Ubuntu package make it 
> impossible to use pkg-config for versions of Ubuntu older than 13.10 
> (like Ubuntu 12.04 which is a LTS). Would you be okay with these flags?

Hmm this is tricky because pkg-config really should be the portable way
to get at these flags. Perhaps we could just fall back to sensible
defaults if pkg-config fails?

On my 12.04 system (with the lttng PPA) it works fine:

$>pkg-config --libs lttng-ust
-llttng-ust -ldl  
$>pkg-config --cflags lttng-ust
-I/usr/include/x86_64-linux-gnu  

Is there a bug raised with the Ubuntu upstream to fix their stable LTTNG package?

-- 
Alex Bennée

[Qemu-devel] [PATCH v4 2/5] Modified the tracetool framework for LTTng 2.x.

[Mohamad Gebai]

* A new format is required to generate definitions for ust tracepoints.
  Files ust_events_h.py and ust_events_c.py define common macros, while
  new function ust_events_h in events.py does the actual definition of
  each tracepoint.
* ust.py generates the new interface for calling userspace tracepoints
  with LTTng 2.x, replacing trace_name(args) to tracepoint(name, args).
* As explained in ust_events_c.py, -Wredundant-decls gives a warning
  when compiling with gcc 4.7 or older. This is specific to lttng-ust so
  for now use a pragma clause to avoid getting a warning.

Signed-off-by: Mohamad Gebai <mohamad.gebai@polymtl.ca>
---
 scripts/tracetool/backend/events.py      |   44 ++++++++++++++++
 scripts/tracetool/backend/ust.py         |   82 ++++++------------------------
 scripts/tracetool/format/ust_events_c.py |   30 +++++++++++
 scripts/tracetool/format/ust_events_h.py |   57 +++++++++++++++++++++
 4 files changed, 147 insertions(+), 66 deletions(-)
 create mode 100644 scripts/tracetool/format/ust_events_c.py
 create mode 100644 scripts/tracetool/format/ust_events_h.py

diff --git a/scripts/tracetool/backend/events.py b/scripts/tracetool/backend/events.py
index 5afce3e..1691c90 100644
--- a/scripts/tracetool/backend/events.py
+++ b/scripts/tracetool/backend/events.py
@@ -6,6 +6,8 @@ Generic event description.
 
 This is a dummy backend to establish appropriate frontend/backend compatibility
 checks.
+
+Generates tracepoint definitions for LTTng userspace tracing when using ust as a backend.
 """
 
 __author__     = "Lluís Vilanova <vilanova@ac.upc.edu>"
@@ -16,8 +18,50 @@ __maintainer__ = "Stefan Hajnoczi"
 __email__      = "stefanha@linux.vnet.ibm.com"
 
 
+from tracetool import out
+
 def events_h(events):
     pass
 
 def events_c(events):
     pass
+
+def ust_events_c(events):
+    pass
+
+def ust_events_h(events):
+    for e in events:
+        if len(e.args) > 0:
+            out('TRACEPOINT_EVENT(',
+                '   qemu,',
+                '   %(name)s,',
+                '   TP_ARGS(%(args)s),',
+                '   TP_FIELDS(',
+                name = e.name,
+                args = ", ".join(", ".join(i) for i in e.args),
+                )
+
+            for t,n in e.args:
+                if ('int' in t) or ('long' in t) or ('unsigned' in t) or ('size_t' in t):
+                    out('       ctf_integer(' + t + ', ' + n + ', ' + n + ')')
+                elif ('double' in t) or ('float' in t):
+                    out('       ctf_float(' + t + ', ' + n + ', ' + n + ')')
+                elif ('char *' in t) or ('char*' in t):
+                    out('       ctf_string(' + n + ', ' + n + ')')
+                elif ('void *' in t) or ('void*' in t):
+                    out('       ctf_integer_hex(unsigned long, ' + n + ', ' + n + ')')
+
+            out('   )',
+                ')',
+                '')
+
+        else:
+            out('TRACEPOINT_EVENT(',
+                '   qemu,',
+                '   %(name)s,',
+                '   TP_ARGS(void),',
+                '   TP_FIELDS()',
+                ')',
+                '',
+                name = e.name,
+                )
diff --git a/scripts/tracetool/backend/ust.py b/scripts/tracetool/backend/ust.py
index ea36995..10c0875 100644
--- a/scripts/tracetool/backend/ust.py
+++ b/scripts/tracetool/backend/ust.py
@@ -18,76 +18,26 @@ from tracetool import out
 
 PUBLIC = True
 
-
 def c(events):
-    out('#include <ust/marker.h>',
-        '#undef mutex_lock',
-        '#undef mutex_unlock',
-        '#undef inline',
-        '#undef wmb',
-        '#include "trace.h"')
+    pass
+
 
+def h(events):
+    out('#include <lttng/tracepoint.h>',
+        '#include "trace/generated-ust-provider.h"',
+        '')
     for e in events:
         argnames = ", ".join(e.args.names())
         if len(e.args) > 0:
-            argnames = ', ' + argnames
-
-            out('DEFINE_TRACE(ust_%(name)s);',
-                '',
-                'static void ust_%(name)s_probe(%(args)s)',
-                '{',
-                '    trace_mark(ust, %(name)s, %(fmt)s%(argnames)s);',
-                '}',
-                name = e.name,
-                args = e.args,
-                fmt = e.fmt,
-                argnames = argnames,
-                )
-
-        else:
-            out('DEFINE_TRACE(ust_%(name)s);',
-                '',
-                'static void ust_%(name)s_probe(%(args)s)',
-                '{',
-                '    trace_mark(ust, %(name)s, UST_MARKER_NOARGS);',
-                '}',
-                name = e.name,
-                args = e.args,
-                )
-
-    # register probes
-    out('',
-        'static void __attribute__((constructor)) trace_init(void)',
-        '{')
-
-    for e in events:
-        out('    register_trace_ust_%(name)s(ust_%(name)s_probe);',
+            argnames = ", " + argnames
+
+        out('static inline void trace_%(name)s(%(args)s)',
+            '{',
+            '    tracepoint(qemu, %(name)s%(tp_args)s);'
+            '',
+            '}',
+            '',
             name = e.name,
+            args = e.args,
+            tp_args = argnames,
             )
-
-    out('}')
-
-
-def h(events):
-    out('#include <ust/tracepoint.h>',
-        '#undef mutex_lock',
-        '#undef mutex_unlock',
-        '#undef inline',
-        '#undef wmb')
-
-    for e in events:
-        if len(e.args) > 0:
-            out('DECLARE_TRACE(ust_%(name)s, TP_PROTO(%(args)s), TP_ARGS(%(argnames)s));',
-                '#define trace_%(name)s trace_ust_%(name)s',
-                name = e.name,
-                args = e.args,
-                argnames = ", ".join(e.args.names()),
-                )
-
-        else:
-            out('_DECLARE_TRACEPOINT_NOARGS(ust_%(name)s);',
-                '#define trace_%(name)s trace_ust_%(name)s',
-                name = e.name,
-                )
-
-    out()
diff --git a/scripts/tracetool/format/ust_events_c.py b/scripts/tracetool/format/ust_events_c.py
new file mode 100644
index 0000000..71328f3
--- /dev/null
+++ b/scripts/tracetool/format/ust_events_c.py
@@ -0,0 +1,30 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+"""
+Generate .c for LTTng ust event description.
+"""
+
+__author__     = "Lluís Vilanova <vilanova@ac.upc.edu>"
+__copyright__  = "Copyright 2012, Lluís Vilanova <vilanova@ac.upc.edu>"
+__license__    = "GPL version 2 or (at your option) any later version"
+
+__maintainer__ = "Stefan Hajnoczi"
+__email__      = "stefanha@linux.vnet.ibm.com"
+
+
+from tracetool import out
+
+
+def begin(events):
+    out('/* This file is autogenerated by tracetool, do not edit. */',
+        '',
+        '#define TRACEPOINT_DEFINE',
+        '#define TRACEPOINT_CREATE_PROBES',
+        '',
+        '/* If gcc version 4.7 or older is used, LTTng ust gives a warning when compiling with',
+        '   -Wredundant-decls.',
+        ' */',
+        '#pragma GCC diagnostic ignored "-Wredundant-decls"',
+        '',
+        '#include "generated-ust-provider.h"')
diff --git a/scripts/tracetool/format/ust_events_h.py b/scripts/tracetool/format/ust_events_h.py
new file mode 100644
index 0000000..b8e3de1
--- /dev/null
+++ b/scripts/tracetool/format/ust_events_h.py
@@ -0,0 +1,57 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+"""
+Generate .h for LTTng ust event description.
+"""
+
+__author__     = "Lluís Vilanova <vilanova@ac.upc.edu>"
+__copyright__  = "Copyright 2012, Lluís Vilanova <vilanova@ac.upc.edu>"
+__license__    = "GPL version 2 or (at your option) any later version"
+
+__maintainer__ = "Stefan Hajnoczi"
+__email__      = "stefanha@linux.vnet.ibm.com"
+
+
+from tracetool import out
+
+
+def begin(events):
+    out('/* This file is autogenerated by tracetool, do not edit. */',
+        '',
+        '#undef TRACEPOINT_PROVIDER',
+        '#define TRACEPOINT_PROVIDER qemu',
+        '',
+        '#undef TRACEPOINT_INCLUDE_FILE',
+        '#define TRACEPOINT_INCLUDE_FILE ./generated-ust-provider.h',
+        '',
+        '#if !defined (TRACE__GENERATED_UST_H) || defined(TRACEPOINT_HEADER_MULTI_READ)',
+        '#define TRACE__GENERATED_UST_H',
+        '',
+        '#include "qemu-common.h"',
+        '#include <lttng/tracepoint.h>',
+        '',
+        '/*',
+        ' * LTTng ust 2.0 does not allow you to use TP_ARGS(void) for tracepoints',
+        ' * requiring no arguments. We define these macros introduced in more recent'
+        ' * versions of LTTng ust as a workaround',
+        ' */',
+        '#ifndef _TP_EXPROTO1',
+        '#define _TP_EXPROTO1(a)               void',
+        '#endif',
+        '#ifndef _TP_EXDATA_PROTO1',
+        '#define _TP_EXDATA_PROTO1(a)          void *__tp_data',
+        '#endif',
+        '#ifndef _TP_EXDATA_VAR1',
+        '#define _TP_EXDATA_VAR1(a)            __tp_data',
+        '#endif',
+        '#ifndef _TP_EXVAR1',
+        '#define _TP_EXVAR1(a)',
+        '#endif',
+        '')
+
+def end(events):
+    out('#endif /* TRACE__GENERATED_UST_H */',
+        '',
+        '/* This part must be outside ifdef protection */',
+        '#include <lttng/tracepoint-event.h>')
-- 
1.7.10.4

[Qemu-devel] [PATCH v4 3/5] Adapt Makefiles to the new LTTng ust interface.

[Mohamad Gebai]

Add generation of new files for LTTng ust.

Signed-off-by: Mohamad Gebai <mohamad.gebai@polymtl.ca>
---
 Makefile            |    5 +++++
 trace/Makefile.objs |   29 +++++++++++++++++++++++++++--
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index 60fb87e..0c797c5 100644
--- a/Makefile
+++ b/Makefile
@@ -50,6 +50,11 @@ GENERATED_HEADERS += trace/generated-tracers-dtrace.h
 endif
 GENERATED_SOURCES += trace/generated-tracers.c
 
+ifeq ($(TRACE_BACKEND),ust)
+GENERATED_HEADERS += trace/generated-ust-provider.h
+GENERATED_SOURCES += trace/generated-ust.c
+endif
+
 # Don't try to regenerate Makefile or configure
 # We don't generate any of them
 Makefile: ;
diff --git a/trace/Makefile.objs b/trace/Makefile.objs
index 3b88e49..00880b3 100644
--- a/trace/Makefile.objs
+++ b/trace/Makefile.objs
@@ -1,9 +1,33 @@
 # -*- mode: makefile -*-
 
 ######################################################################
+# Auto-generated event descriptions for LTTng ust code
+
+ifeq ($(TRACE_BACKEND),ust)
+$(obj)/generated-ust-provider.h: $(obj)/generated-ust-provider.h-timestamp
+$(obj)/generated-ust-provider.h-timestamp: $(SRC_PATH)/trace-events
+	$(call quiet-command,$(TRACETOOL) \
+		--format=ust-events-h \
+		--backend=events \
+		< $< > $@,"  GEN   $(patsubst %-timestamp,%,$@)")
+	@cmp -s $@ $(patsubst %-timestamp,%,$@) || cp $@ $(patsubst %-timestamp,%,$@)
+
+$(obj)/generated-ust.c: $(obj)/generated-ust.c-timestamp $(BUILD_DIR)/config-host.mak
+$(obj)/generated-ust.c-timestamp: $(SRC_PATH)/trace-events
+	$(call quiet-command,$(TRACETOOL) \
+		--format=ust-events-c \
+		--backend=events \
+		< $< > $@,"  GEN   $(patsubst %-timestamp,%,$@)")
+	@cmp -s $@ $(patsubst %-timestamp,%,$@) || cp $@ $(patsubst %-timestamp,%,$@)
+
+ust_provider=$(obj)/generated-ust-provider.h
+ust=$(obj)/generated-ust.c
+endif
+
+######################################################################
 # Auto-generated event descriptions
 
-$(obj)/generated-events.h: $(obj)/generated-events.h-timestamp
+$(obj)/generated-events.h: $(obj)/generated-events.h-timestamp $(ust_provider)
 $(obj)/generated-events.h-timestamp: $(SRC_PATH)/trace-events
 	$(call quiet-command,$(TRACETOOL) \
 		--format=events-h \
@@ -11,7 +35,7 @@ $(obj)/generated-events.h-timestamp: $(SRC_PATH)/trace-events
 		< $< > $@,"  GEN   $(patsubst %-timestamp,%,$@)")
 	@cmp -s $@ $(patsubst %-timestamp,%,$@) || cp $@ $(patsubst %-timestamp,%,$@)
 
-$(obj)/generated-events.c: $(obj)/generated-events.c-timestamp $(BUILD_DIR)/config-host.mak
+$(obj)/generated-events.c: $(obj)/generated-events.c-timestamp $(BUILD_DIR)/config-host.mak $(ust)
 $(obj)/generated-events.c-timestamp: $(SRC_PATH)/trace-events
 	$(call quiet-command,$(TRACETOOL) \
 		--format=events-c \
@@ -77,5 +101,6 @@ util-obj-$(CONFIG_TRACE_DEFAULT) += default.o
 util-obj-$(CONFIG_TRACE_SIMPLE) += simple.o
 util-obj-$(CONFIG_TRACE_STDERR) += stderr.o
 util-obj-$(CONFIG_TRACE_FTRACE) += ftrace.o
+util-obj-$(CONFIG_TRACE_UST) += generated-ust.o
 util-obj-y += control.o
 util-obj-y += generated-tracers.o
-- 
1.7.10.4

Re: [Qemu-devel] [PATCH v4 3/5] Adapt Makefiles to the new LTTng ust interface.

[Stefan Hajnoczi]

On Fri, Oct 18, 2013 at 02:39:51AM -0400, Mohamad Gebai wrote:
>  ######################################################################
> +# Auto-generated event descriptions for LTTng ust code
> +
> +ifeq ($(TRACE_BACKEND),ust)
> +$(obj)/generated-ust-provider.h: $(obj)/generated-ust-provider.h-timestamp
> +$(obj)/generated-ust-provider.h-timestamp: $(SRC_PATH)/trace-events
> +	$(call quiet-command,$(TRACETOOL) \
> +		--format=ust-events-h \
> +		--backend=events \
> +		< $< > $@,"  GEN   $(patsubst %-timestamp,%,$@)")
> +	@cmp -s $@ $(patsubst %-timestamp,%,$@) || cp $@ $(patsubst %-timestamp,%,$@)
> +
> +$(obj)/generated-ust.c: $(obj)/generated-ust.c-timestamp $(BUILD_DIR)/config-host.mak
> +$(obj)/generated-ust.c-timestamp: $(SRC_PATH)/trace-events
> +	$(call quiet-command,$(TRACETOOL) \
> +		--format=ust-events-c \
> +		--backend=events \
> +		< $< > $@,"  GEN   $(patsubst %-timestamp,%,$@)")
> +	@cmp -s $@ $(patsubst %-timestamp,%,$@) || cp $@ $(patsubst %-timestamp,%,$@)
> +
> +ust_provider=$(obj)/generated-ust-provider.h
> +ust=$(obj)/generated-ust.c

I think you can avoid the variables by defining single dependencies
upfront:

$(obj)/generated-events.h: $(obj)/generated-ust-provider.h
$(obj)/generated-events.c: $(obj)/generated-ust.c

[Qemu-devel] [PATCH v4 4/5] Update documentation for LTTng ust tracing

[Mohamad Gebai]

Signed-off-by: Mohamad Gebai <mohamad.gebai@polymtl.ca>
---
 docs/tracing.txt |   36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/docs/tracing.txt b/docs/tracing.txt
index bfc261b..d7be2fd 100644
--- a/docs/tracing.txt
+++ b/docs/tracing.txt
@@ -214,6 +214,42 @@ The "ust" backend uses the LTTng Userspace Tracer library.  There are no
 monitor commands built into QEMU, instead UST utilities should be used to list,
 enable/disable, and dump traces.
 
+Package lttng-tools is required for userspace tracing. You must ensure that the
+current user belongs to the "tracing" group, or manually launch the
+lttng-sessiond daemon for the current user prior to running any instance of
+Qemu.
+
+While running an instrumented Qemu, LTTng should be able to list all available
+events:
+
+    lttng list -u
+
+Create tracing session:
+
+    lttng create mysession
+
+Enable events:
+
+    lttng enable-event qemu:g_malloc -u
+
+Where the events can either be a comma-separated list of events, or "-a" to
+enable all tracepoint events. Start and stop tracing as needed:
+
+    lttng start
+    lttng stop
+
+View the trace:
+
+    lttng view
+
+Destroy tracing session:
+
+    lttng destroy
+
+Babeltrace can be used at any later time to view the trace:
+
+    babeltrace $HOME/lttng-traces/mysession-<date>-<time>
+
 === SystemTap ===
 
 The "dtrace" backend uses DTrace sdt probes but has only been tested with
-- 
1.7.10.4

Re: [Qemu-devel] [PATCH v4 4/5] Update documentation for LTTng ust tracing

[Stefan Hajnoczi]

On Fri, Oct 18, 2013 at 02:39:52AM -0400, Mohamad Gebai wrote:
> +Package lttng-tools is required for userspace tracing. You must ensure that the
> +current user belongs to the "tracing" group, or manually launch the
> +lttng-sessiond daemon for the current user prior to running any instance of
> +Qemu.
> +
> +While running an instrumented Qemu, LTTng should be able to list all available
> +events:

s/Qemu/QEMU/g

[Qemu-devel] [PATCH v4 5/5] Add ust generated files to .gitignore

[Mohamad Gebai]

Signed-off-by: Mohamad Gebai <mohamad.gebai@polymtl.ca>
---
 .gitignore |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/.gitignore b/.gitignore
index 8e1b73f..e024a76 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,6 +9,8 @@ trace/generated-tracers-dtrace.h
 trace/generated-tracers.dtrace
 trace/generated-events.h
 trace/generated-events.c
+trace/generated-ust-provider.h
+trace/generated-ust.c
 libcacard/trace/generated-tracers.c
 *-timestamp
 *-softmmu
-- 
1.7.10.4

Re: [Qemu-devel] [PATCH v4 0/5] Fix UST backend for LTTng 2.x

[Alex Bennée]

mohamad.gebai@gmail.com writes:

> Version 4
>
> * Update documentation

Good stuff. I notice you haven't added my Reviewed-by tags to your
commits. See http://wiki.qemu.org/Contribute/SubmitAPatch.

Anyway it all looks good to me.

Reviewed-by: Alex Bennée <alex@bennee.com>

-- 
Alex Bennée