subject:"Re\: \[Qemu\-devel\] \[PATCH v14 03\/21\] qapi\: add trace events for visitor"

Re: [Qemu-devel] [PATCH v14 03/21] qapi: add trace events for visitor

2016-10-21 Thread Markus Armbruster

"Daniel P. Berrange"  writes:

> On Fri, Oct 07, 2016 at 03:59:07PM +0200, Markus Armbruster wrote:
>> "Daniel P. Berrange"  writes:
>> 
>> > Allow tracing of the operation of visitors
>> >
>> > Signed-off-by: Daniel P. Berrange 
>> > ---
>> >  Makefile.objs  |  1 +
>> >  qapi/qapi-visit-core.c | 27 +++
>> >  qapi/trace-events  | 33 +
>> >  3 files changed, 61 insertions(+)
>> >  create mode 100644 qapi/trace-events
>> >
>> > diff --git a/Makefile.objs b/Makefile.objs
>> > index a8e0224..b3e8aef 100644
>> > --- a/Makefile.objs
>> > +++ b/Makefile.objs
>> > @@ -160,3 +160,4 @@ trace-events-y += target-s390x/trace-events
>> >  trace-events-y += target-ppc/trace-events
>> >  trace-events-y += qom/trace-events
>> >  trace-events-y += linux-user/trace-events
>> > +trace-events-y += qapi/trace-events
>> > diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c
>> > index 55f5876..bfcb276 100644
>> > --- a/qapi/qapi-visit-core.c
>> > +++ b/qapi/qapi-visit-core.c
>> > @@ -19,10 +19,12 @@
>> >  #include "qapi/qmp/qerror.h"
>> >  #include "qapi/visitor.h"
>> >  #include "qapi/visitor-impl.h"
>> > +#include "trace.h"
>> >  
>> >  void visit_complete(Visitor *v, void *opaque)
>> >  {
>> >  assert(v->type != VISITOR_OUTPUT || v->complete);
>> > +trace_visit_complete(v, opaque);
>> 
>> Trace after or before checking the precondition?  Preferences, anyone?
>
> I'm ambivalent, as the assert will crash you either way so
> whether you get a trace event just before the crash seems
> mostly irrelevant to me - the abort stack trace is what
> you'll use to diagnose the crash.

I have a slight preference for trace first, because trace is one call,
while precondition checking can be several.  However, grep shows neither
order is prevalent.  Not worth a respin.

>> >  if (v->complete) {
>> >  v->complete(v, opaque);
>> >  }
>> > @@ -30,6 +32,7 @@ void visit_complete(Visitor *v, void *opaque)
>> >  
>> >  void visit_free(Visitor *v)
>> >  {
>> > +trace_visit_free(v);
>> >  if (v) {
>> >  v->free(v);
>> >  }
>> > @@ -40,6 +43,7 @@ void visit_start_struct(Visitor *v, const char *name, 
>> > void **obj,
>> >  {
>> >  Error *err = NULL;
>> >  
>> > +trace_visit_start_struct(v, name, obj, size);
>> >  if (obj) {
>> >  assert(size);
>> >  assert(!(v->type & VISITOR_OUTPUT) || *obj);
>> > @@ -53,6 +57,7 @@ void visit_start_struct(Visitor *v, const char *name, 
>> > void **obj,
>> >  
>> >  void visit_check_struct(Visitor *v, Error **errp)
>> >  {
>> > +trace_visit_check_struct(v);
>> >  if (v->check_struct) {
>> >  v->check_struct(v, errp);
>> >  }
>> > @@ -60,6 +65,7 @@ void visit_check_struct(Visitor *v, Error **errp)
>> >  
>> >  void visit_end_struct(Visitor *v, void **obj)
>> >  {
>> > +trace_visit_end_struct(v, obj);
>> >  v->end_struct(v, obj);
>> >  }
>> >  
>> > @@ -69,6 +75,7 @@ void visit_start_list(Visitor *v, const char *name, 
>> > GenericList **list,
>> >  Error *err = NULL;
>> >  
>> >  assert(!list || size >= sizeof(GenericList));
>> > +trace_visit_start_list(v, name, list, size);
>> >  v->start_list(v, name, list, size, );
>> >  if (list && (v->type & VISITOR_INPUT)) {
>> >  assert(!(err && *list));
>> > @@ -79,11 +86,13 @@ void visit_start_list(Visitor *v, const char *name, 
>> > GenericList **list,
>> >  GenericList *visit_next_list(Visitor *v, GenericList *tail, size_t size)
>> >  {
>> >  assert(tail && size >= sizeof(GenericList));
>> > +trace_visit_next_list(v, tail, size);
>> >  return v->next_list(v, tail, size);
>> >  }
>> >  
>> >  void visit_end_list(Visitor *v, void **obj)
>> >  {
>> > +trace_visit_end_list(v, obj);
>> >  v->end_list(v, obj);
>> >  }
>> >  
>> > @@ -95,6 +104,7 @@ void visit_start_alternate(Visitor *v, const char *name,
>> >  
>> >  assert(obj && size >= sizeof(GenericAlternate));
>> >  assert(!(v->type & VISITOR_OUTPUT) || *obj);
>> > +trace_visit_start_alternate(v, name, obj, size, promote_int);
>> >  if (v->start_alternate) {
>> >  v->start_alternate(v, name, obj, size, promote_int, );
>> >  }
>> > @@ -106,6 +116,7 @@ void visit_start_alternate(Visitor *v, const char 
>> > *name,
>> >  
>> >  void visit_end_alternate(Visitor *v, void **obj)
>> >  {
>> > +trace_visit_end_alternate(v, obj);
>> >  if (v->end_alternate) {
>> >  v->end_alternate(v, obj);
>> >  }
>> > @@ -113,6 +124,7 @@ void visit_end_alternate(Visitor *v, void **obj)
>> >  
>> >  bool visit_optional(Visitor *v, const char *name, bool *present)
>> >  {
>> > +trace_visit_optional(v, name, present);
>> >  if (v->optional) {
>> >  v->optional(v, name, present);
>> >  }
>> > @@ -127,6 +139,7 @@ bool visit_is_input(Visitor *v)
>> >  void visit_type_int(Visitor *v, const char *name,

Re: [Qemu-devel] [PATCH v14 03/21] qapi: add trace events for visitor

2016-10-07 Thread Daniel P. Berrange

On Fri, Oct 07, 2016 at 03:59:07PM +0200, Markus Armbruster wrote:
> "Daniel P. Berrange"  writes:
> 
> > Allow tracing of the operation of visitors
> >
> > Signed-off-by: Daniel P. Berrange 
> > ---
> >  Makefile.objs  |  1 +
> >  qapi/qapi-visit-core.c | 27 +++
> >  qapi/trace-events  | 33 +
> >  3 files changed, 61 insertions(+)
> >  create mode 100644 qapi/trace-events
> >
> > diff --git a/Makefile.objs b/Makefile.objs
> > index a8e0224..b3e8aef 100644
> > --- a/Makefile.objs
> > +++ b/Makefile.objs
> > @@ -160,3 +160,4 @@ trace-events-y += target-s390x/trace-events
> >  trace-events-y += target-ppc/trace-events
> >  trace-events-y += qom/trace-events
> >  trace-events-y += linux-user/trace-events
> > +trace-events-y += qapi/trace-events
> > diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c
> > index 55f5876..bfcb276 100644
> > --- a/qapi/qapi-visit-core.c
> > +++ b/qapi/qapi-visit-core.c
> > @@ -19,10 +19,12 @@
> >  #include "qapi/qmp/qerror.h"
> >  #include "qapi/visitor.h"
> >  #include "qapi/visitor-impl.h"
> > +#include "trace.h"
> >  
> >  void visit_complete(Visitor *v, void *opaque)
> >  {
> >  assert(v->type != VISITOR_OUTPUT || v->complete);
> > +trace_visit_complete(v, opaque);
> 
> Trace after or before checking the precondition?  Preferences, anyone?

I'm ambivalent, as the assert will crash you either way so
whether you get a trace event just before the crash seems
mostly irrelevant to me - the abort stack trace is what
you'll use to diagnose the crash.

> 
> >  if (v->complete) {
> >  v->complete(v, opaque);
> >  }
> > @@ -30,6 +32,7 @@ void visit_complete(Visitor *v, void *opaque)
> >  
> >  void visit_free(Visitor *v)
> >  {
> > +trace_visit_free(v);
> >  if (v) {
> >  v->free(v);
> >  }
> > @@ -40,6 +43,7 @@ void visit_start_struct(Visitor *v, const char *name, 
> > void **obj,
> >  {
> >  Error *err = NULL;
> >  
> > +trace_visit_start_struct(v, name, obj, size);
> >  if (obj) {
> >  assert(size);
> >  assert(!(v->type & VISITOR_OUTPUT) || *obj);
> > @@ -53,6 +57,7 @@ void visit_start_struct(Visitor *v, const char *name, 
> > void **obj,
> >  
> >  void visit_check_struct(Visitor *v, Error **errp)
> >  {
> > +trace_visit_check_struct(v);
> >  if (v->check_struct) {
> >  v->check_struct(v, errp);
> >  }
> > @@ -60,6 +65,7 @@ void visit_check_struct(Visitor *v, Error **errp)
> >  
> >  void visit_end_struct(Visitor *v, void **obj)
> >  {
> > +trace_visit_end_struct(v, obj);
> >  v->end_struct(v, obj);
> >  }
> >  
> > @@ -69,6 +75,7 @@ void visit_start_list(Visitor *v, const char *name, 
> > GenericList **list,
> >  Error *err = NULL;
> >  
> >  assert(!list || size >= sizeof(GenericList));
> > +trace_visit_start_list(v, name, list, size);
> >  v->start_list(v, name, list, size, );
> >  if (list && (v->type & VISITOR_INPUT)) {
> >  assert(!(err && *list));
> > @@ -79,11 +86,13 @@ void visit_start_list(Visitor *v, const char *name, 
> > GenericList **list,
> >  GenericList *visit_next_list(Visitor *v, GenericList *tail, size_t size)
> >  {
> >  assert(tail && size >= sizeof(GenericList));
> > +trace_visit_next_list(v, tail, size);
> >  return v->next_list(v, tail, size);
> >  }
> >  
> >  void visit_end_list(Visitor *v, void **obj)
> >  {
> > +trace_visit_end_list(v, obj);
> >  v->end_list(v, obj);
> >  }
> >  
> > @@ -95,6 +104,7 @@ void visit_start_alternate(Visitor *v, const char *name,
> >  
> >  assert(obj && size >= sizeof(GenericAlternate));
> >  assert(!(v->type & VISITOR_OUTPUT) || *obj);
> > +trace_visit_start_alternate(v, name, obj, size, promote_int);
> >  if (v->start_alternate) {
> >  v->start_alternate(v, name, obj, size, promote_int, );
> >  }
> > @@ -106,6 +116,7 @@ void visit_start_alternate(Visitor *v, const char *name,
> >  
> >  void visit_end_alternate(Visitor *v, void **obj)
> >  {
> > +trace_visit_end_alternate(v, obj);
> >  if (v->end_alternate) {
> >  v->end_alternate(v, obj);
> >  }
> > @@ -113,6 +124,7 @@ void visit_end_alternate(Visitor *v, void **obj)
> >  
> >  bool visit_optional(Visitor *v, const char *name, bool *present)
> >  {
> > +trace_visit_optional(v, name, present);
> >  if (v->optional) {
> >  v->optional(v, name, present);
> >  }
> > @@ -127,6 +139,7 @@ bool visit_is_input(Visitor *v)
> >  void visit_type_int(Visitor *v, const char *name, int64_t *obj, Error 
> > **errp)
> >  {
> >  assert(obj);
> > +trace_visit_type_int(v, name, obj);
> >  v->type_int64(v, name, obj, errp);
> >  }
> >  
> > @@ -151,6 +164,7 @@ void visit_type_uint8(Visitor *v, const char *name, 
> > uint8_t *obj,
> >Error **errp)
> >  {
> >  uint64_t value = *obj;
> > +trace_visit_type_uint8(v, name,

Re: [Qemu-devel] [PATCH v14 03/21] qapi: add trace events for visitor

2016-10-07 Thread Markus Armbruster

"Daniel P. Berrange"  writes:

> Allow tracing of the operation of visitors
>
> Signed-off-by: Daniel P. Berrange 
> ---
>  Makefile.objs  |  1 +
>  qapi/qapi-visit-core.c | 27 +++
>  qapi/trace-events  | 33 +
>  3 files changed, 61 insertions(+)
>  create mode 100644 qapi/trace-events
>
> diff --git a/Makefile.objs b/Makefile.objs
> index a8e0224..b3e8aef 100644
> --- a/Makefile.objs
> +++ b/Makefile.objs
> @@ -160,3 +160,4 @@ trace-events-y += target-s390x/trace-events
>  trace-events-y += target-ppc/trace-events
>  trace-events-y += qom/trace-events
>  trace-events-y += linux-user/trace-events
> +trace-events-y += qapi/trace-events
> diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c
> index 55f5876..bfcb276 100644
> --- a/qapi/qapi-visit-core.c
> +++ b/qapi/qapi-visit-core.c
> @@ -19,10 +19,12 @@
>  #include "qapi/qmp/qerror.h"
>  #include "qapi/visitor.h"
>  #include "qapi/visitor-impl.h"
> +#include "trace.h"
>  
>  void visit_complete(Visitor *v, void *opaque)
>  {
>  assert(v->type != VISITOR_OUTPUT || v->complete);
> +trace_visit_complete(v, opaque);

Trace after or before checking the precondition?  Preferences, anyone?

>  if (v->complete) {
>  v->complete(v, opaque);
>  }
> @@ -30,6 +32,7 @@ void visit_complete(Visitor *v, void *opaque)
>  
>  void visit_free(Visitor *v)
>  {
> +trace_visit_free(v);
>  if (v) {
>  v->free(v);
>  }
> @@ -40,6 +43,7 @@ void visit_start_struct(Visitor *v, const char *name, void 
> **obj,
>  {
>  Error *err = NULL;
>  
> +trace_visit_start_struct(v, name, obj, size);
>  if (obj) {
>  assert(size);
>  assert(!(v->type & VISITOR_OUTPUT) || *obj);
> @@ -53,6 +57,7 @@ void visit_start_struct(Visitor *v, const char *name, void 
> **obj,
>  
>  void visit_check_struct(Visitor *v, Error **errp)
>  {
> +trace_visit_check_struct(v);
>  if (v->check_struct) {
>  v->check_struct(v, errp);
>  }
> @@ -60,6 +65,7 @@ void visit_check_struct(Visitor *v, Error **errp)
>  
>  void visit_end_struct(Visitor *v, void **obj)
>  {
> +trace_visit_end_struct(v, obj);
>  v->end_struct(v, obj);
>  }
>  
> @@ -69,6 +75,7 @@ void visit_start_list(Visitor *v, const char *name, 
> GenericList **list,
>  Error *err = NULL;
>  
>  assert(!list || size >= sizeof(GenericList));
> +trace_visit_start_list(v, name, list, size);
>  v->start_list(v, name, list, size, );
>  if (list && (v->type & VISITOR_INPUT)) {
>  assert(!(err && *list));
> @@ -79,11 +86,13 @@ void visit_start_list(Visitor *v, const char *name, 
> GenericList **list,
>  GenericList *visit_next_list(Visitor *v, GenericList *tail, size_t size)
>  {
>  assert(tail && size >= sizeof(GenericList));
> +trace_visit_next_list(v, tail, size);
>  return v->next_list(v, tail, size);
>  }
>  
>  void visit_end_list(Visitor *v, void **obj)
>  {
> +trace_visit_end_list(v, obj);
>  v->end_list(v, obj);
>  }
>  
> @@ -95,6 +104,7 @@ void visit_start_alternate(Visitor *v, const char *name,
>  
>  assert(obj && size >= sizeof(GenericAlternate));
>  assert(!(v->type & VISITOR_OUTPUT) || *obj);
> +trace_visit_start_alternate(v, name, obj, size, promote_int);
>  if (v->start_alternate) {
>  v->start_alternate(v, name, obj, size, promote_int, );
>  }
> @@ -106,6 +116,7 @@ void visit_start_alternate(Visitor *v, const char *name,
>  
>  void visit_end_alternate(Visitor *v, void **obj)
>  {
> +trace_visit_end_alternate(v, obj);
>  if (v->end_alternate) {
>  v->end_alternate(v, obj);
>  }
> @@ -113,6 +124,7 @@ void visit_end_alternate(Visitor *v, void **obj)
>  
>  bool visit_optional(Visitor *v, const char *name, bool *present)
>  {
> +trace_visit_optional(v, name, present);
>  if (v->optional) {
>  v->optional(v, name, present);
>  }
> @@ -127,6 +139,7 @@ bool visit_is_input(Visitor *v)
>  void visit_type_int(Visitor *v, const char *name, int64_t *obj, Error **errp)
>  {
>  assert(obj);
> +trace_visit_type_int(v, name, obj);
>  v->type_int64(v, name, obj, errp);
>  }
>  
> @@ -151,6 +164,7 @@ void visit_type_uint8(Visitor *v, const char *name, 
> uint8_t *obj,
>Error **errp)
>  {
>  uint64_t value = *obj;
> +trace_visit_type_uint8(v, name, obj);
>  visit_type_uintN(v, , name, UINT8_MAX, "uint8_t", errp);
>  *obj = value;
>  }

Putting the trace in the middle of the "value = *obj;
visit_type_uintN(v, , ...); *obj = value" pattern makes it less
visible.

Preserving the pattern requires replacing the initializer by an
assignment:

   uint64_t value;

   trace_visit_type_uint8(v, name, obj);
   value = *obj;
   visit_type_uintN(v, , name, UINT8_MAX, "uint8_t", errp);
   *obj = value;

Looks slightly more legible to me.  What do you think?

[...]

Re: [Qemu-devel] [PATCH v14 03/21] qapi: add trace events for visitor

2016-09-30 Thread Eric Blake

On 09/30/2016 09:45 AM, Daniel P. Berrange wrote:
> Allow tracing of the operation of visitors
> 
> Signed-off-by: Daniel P. Berrange 
> ---
>  Makefile.objs  |  1 +
>  qapi/qapi-visit-core.c | 27 +++
>  qapi/trace-events  | 33 +
>  3 files changed, 61 insertions(+)
>  create mode 100644 qapi/trace-events

Reviewed-by: Eric Blake 

> +
> +visit_start_alternate(void *v, const char *name, void *obj, size_t size, 
> bool promote_int) "v=%p name=%s obj=%p size=%zu promote_int=%d"

Unrelated to your patch, but should the trace engines be taught how to
honor line wrapping in the trace files?

-- 
Eric Blake   eblake redhat com+1-919-301-3266
Libvirt virtualization library http://libvirt.org



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Re: [Qemu-devel] [PATCH v14 03/21] qapi: add trace events for visitor

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