[Qemu-devel] [Tracing] [RFC PATCH 0/2] : QMP query Interfaces for tracing

[Qemu-devel] [Tracing] [RFC PATCH 0/2] : QMP query Interfaces for tracing

[Prerna Saxena]

This patch set introduces two QMP interfaces for tracing :

* query-trace        : to list current contents of trace-buffer
* query-trace-events : to list all available trace-events with their state.

-- 
Prerna Saxena

Linux Technology Centre,
IBM Systems and Technology Lab,
Bangalore, India

[Qemu-devel] [Tracing] [RFC PATCH 1/2] : Introduce 'query-trace' & 'query-trace-events' interfaces

[Prerna Saxena]

[PATCH 1/2] Introduce QMP interfaces : query-trace & query-trace-events


Signed-off-by: Prerna Saxena <prerna@linux.vnet.ibm.com>
---
 monitor.c     |   46 ++++++++++++++++++++++++++++++++++++++++++----
 simpletrace.c |   54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 simpletrace.h |    2 ++
 3 files changed, 98 insertions(+), 4 deletions(-)

diff --git a/monitor.c b/monitor.c
index fbb678d..7a150ae 100644
--- a/monitor.c
+++ b/monitor.c
@@ -941,15 +941,33 @@ static void do_info_cpu_stats(Monitor *mon)
 #endif
 
 #if defined(CONFIG_SIMPLE_TRACE)
-static void do_info_trace(Monitor *mon)
+static void do_info_trace_print(Monitor *mon)
 {
     st_print_trace((FILE *)mon, &monitor_fprintf);
 }
 
-static void do_info_trace_events(Monitor *mon)
+static void do_info_trace(Monitor *mon, QObject **ret_data)
+{
+    QList *trace_event_list = NULL;
+
+    st_print_trace_to_qlist(&trace_event_list);
+
+    *ret_data = QOBJECT(trace_event_list);
+}
+
+static void do_info_trace_events_print(Monitor *mon, const QObject *data)
 {
     st_print_trace_events((FILE *)mon, &monitor_fprintf);
 }
+
+static void do_info_trace_events(Monitor *mon, QObject **ret_data)
+{
+    QList *trace_event_list = NULL;
+
+    st_print_trace_events_to_qlist(&trace_event_list);
+
+    *ret_data = QOBJECT(trace_event_list);
+}
 #endif
 
 /**
@@ -2606,14 +2624,16 @@ static const mon_cmd_t info_cmds[] = {
         .args_type  = "",
         .params     = "",
         .help       = "show current contents of trace buffer",
-        .mhandler.info = do_info_trace,
+        .user_print = do_info_trace_print,
+        .mhandler.info_new = do_info_trace,
     },
     {
         .name       = "trace-events",
         .args_type  = "",
         .params     = "",
         .help       = "show available trace-events & their state",
-        .mhandler.info = do_info_trace_events,
+        .user_print = do_info_trace_events_print,
+        .mhandler.info_new = do_info_trace_events,
     },
 #endif
     {
@@ -2748,6 +2768,24 @@ static const mon_cmd_t qmp_query_cmds[] = {
         .mhandler.info_async = do_info_balloon,
         .flags      = MONITOR_CMD_ASYNC,
     },
+#if defined(CONFIG_SIMPLE_TRACE)
+    {
+        .name       = "trace",
+        .args_type  = "",
+        .params     = "",
+        .help       = "show current contents of trace buffer",
+        .user_print = do_info_trace_print,
+        .mhandler.info_new = do_info_trace,
+    },
+    {
+        .name       = "trace-events",
+        .args_type  = "",
+        .params     = "",
+        .help       = "show available trace-events & their state",
+        .user_print = do_info_trace_events_print,
+        .mhandler.info_new = do_info_trace_events,
+    },
+#endif
     { /* NULL */ },
 };
 
diff --git a/simpletrace.c b/simpletrace.c
index f849e42..d1f66b4 100644
--- a/simpletrace.c
+++ b/simpletrace.c
@@ -220,6 +220,39 @@ void st_print_trace(FILE *stream, int (*stream_printf)(FILE *stream, const char
     }
 }
 
+void st_print_trace_to_qlist(QList **tlist)
+{
+    QObject *data;
+    unsigned int i;
+
+    if (!tlist || *tlist )
+        return;
+
+    /* NOTE : This assumes trace_list hasnt already been allocated with a QList.
+     *        The initialization happens here.
+     */
+    *tlist = qlist_new();
+
+    for (i = 0; i < trace_idx; i++) {
+          data = qobject_from_jsonf("{"
+                                    " 'Event': %" PRId64 ","
+                                    " 'arg1': %" PRId64 ","
+                                    " 'arg2': %" PRId64 ","
+                                    " 'arg3': %" PRId64 ","
+                                    " 'arg4': %" PRId64 ","
+                                    " 'arg5': %" PRId64 ","
+                                    " 'arg6': %" PRId64
+                                    "}",
+                                    trace_buf[i].event, trace_buf[i].x1,
+                                    trace_buf[i].x2, trace_buf[i].x3,
+                                    trace_buf[i].x4, trace_buf[i].x5,
+                                    trace_buf[i].x6);
+          qlist_append_obj(*tlist, data);
+    }
+
+    return;
+}
+
 void st_print_trace_events(FILE *stream, int (*stream_printf)(FILE *stream, const char *fmt, ...))
 {
     unsigned int i;
@@ -230,6 +263,27 @@ void st_print_trace_events(FILE *stream, int (*stream_printf)(FILE *stream, cons
     }
 }
 
+void st_print_trace_events_to_qlist(QList **tlist)
+{
+    QObject *data;
+    unsigned int i;
+
+    if (!tlist || *tlist )
+        return;
+
+    /* NOTE : This assumes trace_list hasnt already been allocated with a QList.
+     *        The initialization happens here.
+     */
+    *tlist = qlist_new();
+
+    for (i = 0; i < NR_TRACE_EVENTS; i++) {
+          data = qobject_from_jsonf("{ 'name': %s, 'eventID': %d, 'state': %d }", trace_list[i].tp_name, i, trace_list[i].state);
+          qlist_append_obj(*tlist, data);
+    }
+
+    return;
+}
+
 static TraceEvent* find_trace_event_by_name(const char *tname)
 {
     unsigned int i;
diff --git a/simpletrace.h b/simpletrace.h
index cf35897..9c1f535 100644
--- a/simpletrace.h
+++ b/simpletrace.h
@@ -14,6 +14,8 @@
 #include <stdint.h>
 #include <stdbool.h>
 #include <stdio.h>
+#include "qdict.h"
+#include "qjson.h"
 
 typedef uint64_t TraceEventID;
 
-- 
1.7.2.2



-- 
Prerna Saxena

Linux Technology Centre,
IBM Systems and Technology Lab,
Bangalore, India

[Qemu-devel] [Tracing] [RFC PATCH 2/2] : Documentation for QMP interfaces

[Prerna Saxena]

[PATCH 2/2] Add documentation for QMP commands: query-trace & query-trace-events.


Signed-off-by: Prerna Saxena <prerna@linux.vnet.ibm.com>
---
 qmp-commands.hx |   53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 53 insertions(+), 0 deletions(-)

diff --git a/qmp-commands.hx b/qmp-commands.hx
index 793cf1c..9a48984 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -1539,3 +1539,56 @@ Example:
 
 EQMP
 
+SQMP
+query-trace
+-------------
+
+Show contents of trace buffer.
+
+Returns a set of json-objects containing the following data:
+
+- "Event": Event ID for the trace-event(json-int)
+- "arg1 .. arg6": Arguments logged by the trace-event (json-int)
+
+Example:
+
+-> { "execute": "query-trace" }
+<- {
+      "return":{
+         "Event": 22,
+         "arg6": 0,
+         "arg5": 0,
+         "arg4": 0,
+         "arg3": 0,
+         "arg2": 80,
+         "arg1": 886
+       }
+   }
+
+EQMP
+
+SQMP
+query-trace-events
+------------------
+
+Show all available trace-events & their state.
+
+Returns a set of json-objects containing the following data:
+
+- "name": Name of Trace-event (json-string)
+- "state": State of trace-event [ '0': inactive; '1':active  ] (json-int)
+- "eventID": Event ID of Trace-event (json-int)
+
+Example:
+
+-> { "execute": "query-trace-events" }
+<- {
+      "return":{
+         "name": "qemu_malloc",
+         "state": 0,
+         "eventID": 0
+      }
+   }
+
+EQMP
+
-- 
1.7.2.2



-- 
Prerna Saxena

Linux Technology Centre,
IBM Systems and Technology Lab,
Bangalore, India

[Qemu-devel] Re: [Tracing] [RFC PATCH 1/2] : Introduce 'query-trace' & 'query-trace-events' interfaces

[Stefan Hajnoczi]

On Thu, Oct 14, 2010 at 11:26:04AM +0530, Prerna Saxena wrote:
> [PATCH 1/2] Introduce QMP interfaces : query-trace & query-trace-events
> 
> 
> Signed-off-by: Prerna Saxena <prerna@linux.vnet.ibm.com>
> ---
>  monitor.c     |   46 ++++++++++++++++++++++++++++++++++++++++++----
>  simpletrace.c |   54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  simpletrace.h |    2 ++
>  3 files changed, 98 insertions(+), 4 deletions(-)
> 
> diff --git a/monitor.c b/monitor.c
> index fbb678d..7a150ae 100644
> --- a/monitor.c
> +++ b/monitor.c
> @@ -941,15 +941,33 @@ static void do_info_cpu_stats(Monitor *mon)
>  #endif
> 
>  #if defined(CONFIG_SIMPLE_TRACE)
> -static void do_info_trace(Monitor *mon)
> +static void do_info_trace_print(Monitor *mon)
>  {
>      st_print_trace((FILE *)mon, &monitor_fprintf);
>  }
> 
> -static void do_info_trace_events(Monitor *mon)
> +static void do_info_trace(Monitor *mon, QObject **ret_data)
> +{
> +    QList *trace_event_list = NULL;
> +
> +    st_print_trace_to_qlist(&trace_event_list);
> +
> +    *ret_data = QOBJECT(trace_event_list);
> +}
> +
> +static void do_info_trace_events_print(Monitor *mon, const QObject *data)
>  {
>      st_print_trace_events((FILE *)mon, &monitor_fprintf);
>  }
> +
> +static void do_info_trace_events(Monitor *mon, QObject **ret_data)
> +{
> +    QList *trace_event_list = NULL;
> +
> +    st_print_trace_events_to_qlist(&trace_event_list);
> +
> +    *ret_data = QOBJECT(trace_event_list);
> +}
>  #endif
> 
>  /**
> @@ -2606,14 +2624,16 @@ static const mon_cmd_t info_cmds[] = {
>          .args_type  = "",
>          .params     = "",
>          .help       = "show current contents of trace buffer",
> -        .mhandler.info = do_info_trace,
> +        .user_print = do_info_trace_print,
> +        .mhandler.info_new = do_info_trace,
>      },
>      {
>          .name       = "trace-events",
>          .args_type  = "",
>          .params     = "",
>          .help       = "show available trace-events & their state",
> -        .mhandler.info = do_info_trace_events,
> +        .user_print = do_info_trace_events_print,
> +        .mhandler.info_new = do_info_trace_events,
>      },
>  #endif
>      {
> @@ -2748,6 +2768,24 @@ static const mon_cmd_t qmp_query_cmds[] = {
>          .mhandler.info_async = do_info_balloon,
>          .flags      = MONITOR_CMD_ASYNC,
>      },
> +#if defined(CONFIG_SIMPLE_TRACE)
> +    {
> +        .name       = "trace",
> +        .args_type  = "",
> +        .params     = "",
> +        .help       = "show current contents of trace buffer",
> +        .user_print = do_info_trace_print,
> +        .mhandler.info_new = do_info_trace,
> +    },
> +    {
> +        .name       = "trace-events",
> +        .args_type  = "",
> +        .params     = "",
> +        .help       = "show available trace-events & their state",
> +        .user_print = do_info_trace_events_print,
> +        .mhandler.info_new = do_info_trace_events,
> +    },
> +#endif
>      { /* NULL */ },
>  };
> 
> diff --git a/simpletrace.c b/simpletrace.c
> index f849e42..d1f66b4 100644
> --- a/simpletrace.c
> +++ b/simpletrace.c
> @@ -220,6 +220,39 @@ void st_print_trace(FILE *stream, int (*stream_printf)(FILE *stream, const char
>      }
>  }
> 
> +void st_print_trace_to_qlist(QList **tlist)
> +{
> +    QObject *data;
> +    unsigned int i;
> +
> +    if (!tlist || *tlist )
> +        return;

This silences bugs.  If you want to check these please use asserts.

> +
> +    /* NOTE : This assumes trace_list hasnt already been allocated with a QList.
> +     *        The initialization happens here.
> +     */

This should be in a doc comment for this function to make it clear that
tlist will be allocated a new list.

> +    *tlist = qlist_new();
> +
> +    for (i = 0; i < trace_idx; i++) {
> +          data = qobject_from_jsonf("{"
> +                                    " 'Event': %" PRId64 ","
> +                                    " 'arg1': %" PRId64 ","
> +                                    " 'arg2': %" PRId64 ","
> +                                    " 'arg3': %" PRId64 ","
> +                                    " 'arg4': %" PRId64 ","
> +                                    " 'arg5': %" PRId64 ","
> +                                    " 'arg6': %" PRId64
> +                                    "}",
> +                                    trace_buf[i].event, trace_buf[i].x1,
> +                                    trace_buf[i].x2, trace_buf[i].x3,
> +                                    trace_buf[i].x4, trace_buf[i].x5,
> +                                    trace_buf[i].x6);
> +          qlist_append_obj(*tlist, data);
> +    }
> +
> +    return;

Not needed for a void function and not used in QEMU coding style.

> +}
> +
>  void st_print_trace_events(FILE *stream, int (*stream_printf)(FILE *stream, const char *fmt, ...))
>  {
>      unsigned int i;
> @@ -230,6 +263,27 @@ void st_print_trace_events(FILE *stream, int (*stream_printf)(FILE *stream, cons
>      }
>  }
> 
> +void st_print_trace_events_to_qlist(QList **tlist)

The same comments apply to this function.

> +{
> +    QObject *data;
> +    unsigned int i;
> +
> +    if (!tlist || *tlist )
> +        return;
> +
> +    /* NOTE : This assumes trace_list hasnt already been allocated with a QList.
> +     *        The initialization happens here.
> +     */
> +    *tlist = qlist_new();
> +
> +    for (i = 0; i < NR_TRACE_EVENTS; i++) {
> +          data = qobject_from_jsonf("{ 'name': %s, 'eventID': %d, 'state': %d }", trace_list[i].tp_name, i, trace_list[i].state);
> +          qlist_append_obj(*tlist, data);
> +    }
> +
> +    return;
> +}
> +
>  static TraceEvent* find_trace_event_by_name(const char *tname)
>  {
>      unsigned int i;
> diff --git a/simpletrace.h b/simpletrace.h
> index cf35897..9c1f535 100644
> --- a/simpletrace.h
> +++ b/simpletrace.h
> @@ -14,6 +14,8 @@
>  #include <stdint.h>
>  #include <stdbool.h>
>  #include <stdio.h>
> +#include "qdict.h"
> +#include "qjson.h"

Where are the prototypes for st_print_trace_to_qlist() and st_print_trace_events_to_qlist()?

Stefan

[Qemu-devel] Re: [Tracing] [RFC PATCH 2/2] : Documentation for QMP interfaces

[Stefan Hajnoczi]

On Thu, Oct 14, 2010 at 11:31:20AM +0530, Prerna Saxena wrote:
> [PATCH 2/2] Add documentation for QMP commands: query-trace & query-trace-events.
> 
> 
> Signed-off-by: Prerna Saxena <prerna@linux.vnet.ibm.com>
> ---
>  qmp-commands.hx |   53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 53 insertions(+), 0 deletions(-)
> 
> diff --git a/qmp-commands.hx b/qmp-commands.hx
> index 793cf1c..9a48984 100644
> --- a/qmp-commands.hx
> +++ b/qmp-commands.hx
> @@ -1539,3 +1539,56 @@ Example:
> 
>  EQMP
> 
> +SQMP
> +query-trace
> +-------------
> +
> +Show contents of trace buffer.
> +
> +Returns a set of json-objects containing the following data:
> +
> +- "Event": Event ID for the trace-event(json-int)

JSON names are lowercase like the C fields they represent, please use
"event".

> +- "arg1 .. arg6": Arguments logged by the trace-event (json-int)

What about the timestamp_ns field?

> +
> +Example:
> +
> +-> { "execute": "query-trace" }
> +<- {
> +      "return":{
> +         "Event": 22,
> +         "arg6": 0,
> +         "arg5": 0,
> +         "arg4": 0,
> +         "arg3": 0,
> +         "arg2": 80,
> +         "arg1": 886
> +       }
> +   }
> +
> +EQMP
> +
> +SQMP
> +query-trace-events
> +------------------
> +
> +Show all available trace-events & their state.
> +
> +Returns a set of json-objects containing the following data:
> +
> +- "name": Name of Trace-event (json-string)
> +- "state": State of trace-event [ '0': inactive; '1':active  ] (json-int)
> +- "eventID": Event ID of Trace-event (json-int)
> +
> +Example:
> +
> +-> { "execute": "query-trace-events" }
> +<- {
> +      "return":{
> +         "name": "qemu_malloc",
> +         "state": 0,
> +         "eventID": 0
> +      }
> +   }
> +
> +EQMP
> +
> -- 
> 1.7.2.2
> 
> 
> 
> -- 
> Prerna Saxena
> 
> Linux Technology Centre,
> IBM Systems and Technology Lab,
> Bangalore, India
>