* [Qemu-devel] [PATCH v3 0/2] trace: Simplify late initialization
@ 2016-08-11 16:11 Lluís Vilanova
2016-08-11 16:11 ` [Qemu-devel] [PATCH v3 1/2] trace: Remove 'trace_events_dstate_init' Lluís Vilanova
2016-08-11 16:11 ` [Qemu-devel] [PATCH v3 2/2] trace: Avoid implicit bool->integer conversions Lluís Vilanova
0 siblings, 2 replies; 7+ messages in thread
From: Lluís Vilanova @ 2016-08-11 16:11 UTC (permalink / raw)
To: qemu-devel; +Cc: Paolo Bonzini, 'Daniel P. Berrange', Stefan Hajnoczi
Removes the need for 'trace_events_dstate_init' and does a little cleanup in how
state values are modified (to avoid implicit conversions from bool).
Changes in v2
=============
* Fix late-init state value [Daniel P. Berrange].
Changes in v3
=============
* Avoid implicit conversions from bool to integers (second patch) [Daniel
P. Berrange].
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
---
Lluís Vilanova (2):
trace: Remove 'trace_events_dstate_init'
trace: Avoid implicit bool->integer conversions
stubs/trace-control.c | 14 ++++++++++++--
trace/control-target.c | 23 +++++++++++++++++++++--
trace/control.c | 23 ++++++++++-------------
trace/control.h | 3 +++
trace/event-internal.h | 1 +
5 files changed, 47 insertions(+), 17 deletions(-)
To: qemu-devel@nongnu.org
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: 'Daniel P. Berrange' <berrange@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Qemu-devel] [PATCH v3 1/2] trace: Remove 'trace_events_dstate_init'
2016-08-11 16:11 [Qemu-devel] [PATCH v3 0/2] trace: Simplify late initialization Lluís Vilanova
@ 2016-08-11 16:11 ` Lluís Vilanova
2016-08-11 16:11 ` [Qemu-devel] [PATCH v3 2/2] trace: Avoid implicit bool->integer conversions Lluís Vilanova
1 sibling, 0 replies; 7+ messages in thread
From: Lluís Vilanova @ 2016-08-11 16:11 UTC (permalink / raw)
To: qemu-devel; +Cc: Paolo Bonzini, 'Daniel P. Berrange', Stefan Hajnoczi
Removes the event state array used for early initialization. Since only
events with the "vcpu" property need a late initialization fixup,
threats their initialization specially.
Assumes that the user won't touch the state of "vcpu" events between
early and late initialization (e.g., through QMP).
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
---
stubs/trace-control.c | 5 +++++
trace/control-target.c | 9 +++++++++
trace/control.c | 23 ++++++++++-------------
trace/control.h | 3 +++
trace/event-internal.h | 1 +
5 files changed, 28 insertions(+), 13 deletions(-)
diff --git a/stubs/trace-control.c b/stubs/trace-control.c
index fe59836..3740c38 100644
--- a/stubs/trace-control.c
+++ b/stubs/trace-control.c
@@ -11,6 +11,11 @@
#include "trace/control.h"
+void trace_event_set_state_dynamic_init(TraceEvent *ev, bool state)
+{
+ trace_event_set_state_dynamic(ev, state);
+}
+
void trace_event_set_state_dynamic(TraceEvent *ev, bool state)
{
TraceEventID id;
diff --git a/trace/control-target.c b/trace/control-target.c
index 74c029a..4ee3733 100644
--- a/trace/control-target.c
+++ b/trace/control-target.c
@@ -13,6 +13,15 @@
#include "translate-all.h"
+void trace_event_set_state_dynamic_init(TraceEvent *ev, bool state)
+{
+ TraceEventID id = trace_event_get_id(ev);
+ assert(trace_event_get_state_static(ev));
+ /* Ignore "vcpu" property, since no vCPUs have been created yet */
+ trace_events_enabled_count += state - trace_events_dstate[id];
+ trace_events_dstate[id] = state;
+}
+
void trace_event_set_state_dynamic(TraceEvent *ev, bool state)
{
CPUState *vcpu;
diff --git a/trace/control.c b/trace/control.c
index d173c09..f6e06cc 100644
--- a/trace/control.c
+++ b/trace/control.c
@@ -31,8 +31,6 @@ int trace_events_enabled_count;
* - true : Integral counting the number of vCPUs that have this event enabled.
*/
uint16_t trace_events_dstate[TRACE_EVENT_COUNT];
-/* Marks events for late vCPU state init */
-static bool trace_events_dstate_init[TRACE_EVENT_COUNT];
QemuOptsList qemu_trace_opts = {
.name = "trace",
@@ -142,10 +140,7 @@ static void do_trace_enable_events(const char *line_buf)
TraceEvent *ev = NULL;
while ((ev = trace_event_pattern(line_ptr, ev)) != NULL) {
if (trace_event_get_state_static(ev)) {
- /* start tracing */
- trace_event_set_state_dynamic(ev, enable);
- /* mark for late vCPU init */
- trace_events_dstate_init[ev->id] = true;
+ trace_event_set_state_dynamic_init(ev, enable);
}
}
} else {
@@ -157,10 +152,7 @@ static void do_trace_enable_events(const char *line_buf)
error_report("WARNING: trace event '%s' is not traceable",
line_ptr);
} else {
- /* start tracing */
- trace_event_set_state_dynamic(ev, enable);
- /* mark for late vCPU init */
- trace_events_dstate_init[ev->id] = true;
+ trace_event_set_state_dynamic_init(ev, enable);
}
}
}
@@ -275,9 +267,14 @@ void trace_init_vcpu_events(void)
{
TraceEvent *ev = NULL;
while ((ev = trace_event_pattern("*", ev)) != NULL) {
- if (trace_event_is_vcpu(ev) &&
- trace_event_get_state_static(ev) &&
- trace_events_dstate_init[ev->id]) {
+ if (trace_event_is_vcpu(ev) && trace_event_get_state_dynamic(ev)) {
+ TraceEventID id = trace_event_get_id(ev);
+ /* check preconditions */
+ assert(trace_events_dstate[id] == 1);
+ /* disable early-init state ... */
+ trace_events_dstate[id] = 0;
+ trace_events_enabled_count--;
+ /* ... and properly re-enable */
trace_event_set_state_dynamic(ev, true);
}
}
diff --git a/trace/control.h b/trace/control.h
index 0413b28..27a16fc 100644
--- a/trace/control.h
+++ b/trace/control.h
@@ -274,6 +274,9 @@ char *trace_opt_parse(const char *optarg);
*
* Re-synchronize initial event state with vCPUs (which can be created after
* trace_init_events()).
+ *
+ * Precondition: event states won't be changed between trace_enable_events() and
+ * trace_init_vcpu_events() (e.g., through QMP).
*/
void trace_init_vcpu_events(void);
diff --git a/trace/event-internal.h b/trace/event-internal.h
index 5d8fa97..074faf6 100644
--- a/trace/event-internal.h
+++ b/trace/event-internal.h
@@ -29,5 +29,6 @@ typedef struct TraceEvent {
const bool sstate;
} TraceEvent;
+void trace_event_set_state_dynamic_init(TraceEvent *ev, bool state);
#endif /* TRACE__EVENT_INTERNAL_H */
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [Qemu-devel] [PATCH v3 2/2] trace: Avoid implicit bool->integer conversions
2016-08-11 16:11 [Qemu-devel] [PATCH v3 0/2] trace: Simplify late initialization Lluís Vilanova
2016-08-11 16:11 ` [Qemu-devel] [PATCH v3 1/2] trace: Remove 'trace_events_dstate_init' Lluís Vilanova
@ 2016-08-11 16:11 ` Lluís Vilanova
2016-08-11 16:31 ` Daniel P. Berrange
1 sibling, 1 reply; 7+ messages in thread
From: Lluís Vilanova @ 2016-08-11 16:11 UTC (permalink / raw)
To: qemu-devel; +Cc: Paolo Bonzini, 'Daniel P. Berrange', Stefan Hajnoczi
An explicit if/else is clearer than arithmetic assuming #true is 1,
while the compiler should be able to generate just as optimal code.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
---
stubs/trace-control.c | 9 +++++++--
trace/control-target.c | 18 ++++++++++++++----
2 files changed, 21 insertions(+), 6 deletions(-)
diff --git a/stubs/trace-control.c b/stubs/trace-control.c
index 3740c38..099c2b5 100644
--- a/stubs/trace-control.c
+++ b/stubs/trace-control.c
@@ -21,8 +21,13 @@ void trace_event_set_state_dynamic(TraceEvent *ev, bool state)
TraceEventID id;
assert(trace_event_get_state_static(ev));
id = trace_event_get_id(ev);
- trace_events_enabled_count += state - trace_events_dstate[id];
- trace_events_dstate[id] = state;
+ if (state) {
+ trace_events_enabled_count++;
+ trace_events_dstate[id] = 1;
+ } else {
+ trace_events_enabled_count--;
+ trace_events_dstate[id] = 0;
+ }
}
void trace_event_set_vcpu_state_dynamic(CPUState *vcpu,
diff --git a/trace/control-target.c b/trace/control-target.c
index 4ee3733..4e2e727 100644
--- a/trace/control-target.c
+++ b/trace/control-target.c
@@ -18,8 +18,13 @@ void trace_event_set_state_dynamic_init(TraceEvent *ev, bool state)
TraceEventID id = trace_event_get_id(ev);
assert(trace_event_get_state_static(ev));
/* Ignore "vcpu" property, since no vCPUs have been created yet */
- trace_events_enabled_count += state - trace_events_dstate[id];
- trace_events_dstate[id] = state;
+ if (state) {
+ trace_events_enabled_count++;
+ trace_events_dstate[id] = 1;
+ } else {
+ trace_events_enabled_count--;
+ trace_events_dstate[id] = 0;
+ }
}
void trace_event_set_state_dynamic(TraceEvent *ev, bool state)
@@ -32,8 +37,13 @@ void trace_event_set_state_dynamic(TraceEvent *ev, bool state)
}
} else {
TraceEventID id = trace_event_get_id(ev);
- trace_events_enabled_count += state - trace_events_dstate[id];
- trace_events_dstate[id] = state;
+ if (state) {
+ trace_events_enabled_count++;
+ trace_events_dstate[id] = 1;
+ } else {
+ trace_events_enabled_count--;
+ trace_events_dstate[id] = 0;
+ }
}
}
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [Qemu-devel] [PATCH v3 2/2] trace: Avoid implicit bool->integer conversions
2016-08-11 16:11 ` [Qemu-devel] [PATCH v3 2/2] trace: Avoid implicit bool->integer conversions Lluís Vilanova
@ 2016-08-11 16:31 ` Daniel P. Berrange
2016-08-11 16:41 ` Lluís Vilanova
0 siblings, 1 reply; 7+ messages in thread
From: Daniel P. Berrange @ 2016-08-11 16:31 UTC (permalink / raw)
To: Lluís Vilanova; +Cc: qemu-devel, Paolo Bonzini, Stefan Hajnoczi
On Thu, Aug 11, 2016 at 06:11:29PM +0200, Lluís Vilanova wrote:
> An explicit if/else is clearer than arithmetic assuming #true is 1,
> while the compiler should be able to generate just as optimal code.
>
> Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
> ---
> stubs/trace-control.c | 9 +++++++--
> trace/control-target.c | 18 ++++++++++++++----
> 2 files changed, 21 insertions(+), 6 deletions(-)
>
> diff --git a/stubs/trace-control.c b/stubs/trace-control.c
> index 3740c38..099c2b5 100644
> --- a/stubs/trace-control.c
> +++ b/stubs/trace-control.c
> @@ -21,8 +21,13 @@ void trace_event_set_state_dynamic(TraceEvent *ev, bool state)
> TraceEventID id;
> assert(trace_event_get_state_static(ev));
> id = trace_event_get_id(ev);
> - trace_events_enabled_count += state - trace_events_dstate[id];
> - trace_events_dstate[id] = state;
> + if (state) {
> + trace_events_enabled_count++;
> + trace_events_dstate[id] = 1;
> + } else {
> + trace_events_enabled_count--;
SHouldn't this be trace_events_enabled_count -= trace_events_dstate[id];
as it is possible to call this method for a trace event that is a per-vcpu
event
> + trace_events_dstate[id] = 0;
> + }
> }
>
> void trace_event_set_vcpu_state_dynamic(CPUState *vcpu,
> diff --git a/trace/control-target.c b/trace/control-target.c
> index 4ee3733..4e2e727 100644
> --- a/trace/control-target.c
> +++ b/trace/control-target.c
> @@ -18,8 +18,13 @@ void trace_event_set_state_dynamic_init(TraceEvent *ev, bool state)
> TraceEventID id = trace_event_get_id(ev);
> assert(trace_event_get_state_static(ev));
> /* Ignore "vcpu" property, since no vCPUs have been created yet */
> - trace_events_enabled_count += state - trace_events_dstate[id];
> - trace_events_dstate[id] = state;
> + if (state) {
> + trace_events_enabled_count++;
> + trace_events_dstate[id] = 1;
> + } else {
> + trace_events_enabled_count--;
> + trace_events_dstate[id] = 0;
> + }
> }
>
> void trace_event_set_state_dynamic(TraceEvent *ev, bool state)
> @@ -32,8 +37,13 @@ void trace_event_set_state_dynamic(TraceEvent *ev, bool state)
> }
> } else {
> TraceEventID id = trace_event_get_id(ev);
> - trace_events_enabled_count += state - trace_events_dstate[id];
> - trace_events_dstate[id] = state;
> + if (state) {
> + trace_events_enabled_count++;
> + trace_events_dstate[id] = 1;
> + } else {
> + trace_events_enabled_count--;
> + trace_events_dstate[id] = 0;
> + }
> }
> }
>
>
Regards,
Daniel
--
|: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org -o- http://virt-manager.org :|
|: http://autobuild.org -o- http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [Qemu-devel] [PATCH v3 2/2] trace: Avoid implicit bool->integer conversions
2016-08-11 16:31 ` Daniel P. Berrange
@ 2016-08-11 16:41 ` Lluís Vilanova
2016-08-11 16:51 ` Daniel P. Berrange
0 siblings, 1 reply; 7+ messages in thread
From: Lluís Vilanova @ 2016-08-11 16:41 UTC (permalink / raw)
To: Daniel P. Berrange; +Cc: Paolo Bonzini, qemu-devel, Stefan Hajnoczi
Daniel P Berrange writes:
> On Thu, Aug 11, 2016 at 06:11:29PM +0200, Lluís Vilanova wrote:
>> An explicit if/else is clearer than arithmetic assuming #true is 1,
>> while the compiler should be able to generate just as optimal code.
>>
>> Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
>> ---
>> stubs/trace-control.c | 9 +++++++--
>> trace/control-target.c | 18 ++++++++++++++----
>> 2 files changed, 21 insertions(+), 6 deletions(-)
>>
>> diff --git a/stubs/trace-control.c b/stubs/trace-control.c
>> index 3740c38..099c2b5 100644
>> --- a/stubs/trace-control.c
>> +++ b/stubs/trace-control.c
>> @@ -21,8 +21,13 @@ void trace_event_set_state_dynamic(TraceEvent *ev, bool state)
>> TraceEventID id;
>> assert(trace_event_get_state_static(ev));
>> id = trace_event_get_id(ev);
>> - trace_events_enabled_count += state - trace_events_dstate[id];
>> - trace_events_dstate[id] = state;
>> + if (state) {
>> + trace_events_enabled_count++;
>> + trace_events_dstate[id] = 1;
>> + } else {
>> + trace_events_enabled_count--;
> SHouldn't this be trace_events_enabled_count -= trace_events_dstate[id];
> as it is possible to call this method for a trace event that is a per-vcpu
> event
The "stub" code will never have vCPUs around, it's used by qemu-img and the like
(any program without "target" code).
I can send a v4 explicitly commenting that if you think that's necessary.
Thanks,
Lluis
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [Qemu-devel] [PATCH v3 2/2] trace: Avoid implicit bool->integer conversions
2016-08-11 16:41 ` Lluís Vilanova
@ 2016-08-11 16:51 ` Daniel P. Berrange
2016-08-11 17:22 ` Lluís Vilanova
0 siblings, 1 reply; 7+ messages in thread
From: Daniel P. Berrange @ 2016-08-11 16:51 UTC (permalink / raw)
To: Paolo Bonzini, qemu-devel, Stefan Hajnoczi
On Thu, Aug 11, 2016 at 06:41:36PM +0200, Lluís Vilanova wrote:
> Daniel P Berrange writes:
>
> > On Thu, Aug 11, 2016 at 06:11:29PM +0200, Lluís Vilanova wrote:
> >> An explicit if/else is clearer than arithmetic assuming #true is 1,
> >> while the compiler should be able to generate just as optimal code.
> >>
> >> Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
> >> ---
> >> stubs/trace-control.c | 9 +++++++--
> >> trace/control-target.c | 18 ++++++++++++++----
> >> 2 files changed, 21 insertions(+), 6 deletions(-)
> >>
> >> diff --git a/stubs/trace-control.c b/stubs/trace-control.c
> >> index 3740c38..099c2b5 100644
> >> --- a/stubs/trace-control.c
> >> +++ b/stubs/trace-control.c
> >> @@ -21,8 +21,13 @@ void trace_event_set_state_dynamic(TraceEvent *ev, bool state)
> >> TraceEventID id;
> >> assert(trace_event_get_state_static(ev));
> >> id = trace_event_get_id(ev);
> >> - trace_events_enabled_count += state - trace_events_dstate[id];
> >> - trace_events_dstate[id] = state;
> >> + if (state) {
> >> + trace_events_enabled_count++;
> >> + trace_events_dstate[id] = 1;
> >> + } else {
> >> + trace_events_enabled_count--;
>
> > SHouldn't this be trace_events_enabled_count -= trace_events_dstate[id];
> > as it is possible to call this method for a trace event that is a per-vcpu
> > event
>
> The "stub" code will never have vCPUs around, it's used by qemu-img and the like
> (any program without "target" code).
I just picked the first example of that in this file - you've got the same
pattern in the other 2 places you change
Regards,
Daniel
--
|: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org -o- http://virt-manager.org :|
|: http://autobuild.org -o- http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [Qemu-devel] [PATCH v3 2/2] trace: Avoid implicit bool->integer conversions
2016-08-11 16:51 ` Daniel P. Berrange
@ 2016-08-11 17:22 ` Lluís Vilanova
0 siblings, 0 replies; 7+ messages in thread
From: Lluís Vilanova @ 2016-08-11 17:22 UTC (permalink / raw)
To: Daniel P. Berrange; +Cc: Paolo Bonzini, qemu-devel, Stefan Hajnoczi
Daniel P Berrange writes:
> On Thu, Aug 11, 2016 at 06:41:36PM +0200, Lluís Vilanova wrote:
>> Daniel P Berrange writes:
>>
>> > On Thu, Aug 11, 2016 at 06:11:29PM +0200, Lluís Vilanova wrote:
>> >> An explicit if/else is clearer than arithmetic assuming #true is 1,
>> >> while the compiler should be able to generate just as optimal code.
>> >>
>> >> Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
>> >> ---
>> >> stubs/trace-control.c | 9 +++++++--
>> >> trace/control-target.c | 18 ++++++++++++++----
>> >> 2 files changed, 21 insertions(+), 6 deletions(-)
>> >>
>> >> diff --git a/stubs/trace-control.c b/stubs/trace-control.c
>> >> index 3740c38..099c2b5 100644
>> >> --- a/stubs/trace-control.c
>> >> +++ b/stubs/trace-control.c
>> >> @@ -21,8 +21,13 @@ void trace_event_set_state_dynamic(TraceEvent *ev, bool state)
>> >> TraceEventID id;
>> >> assert(trace_event_get_state_static(ev));
>> >> id = trace_event_get_id(ev);
>> >> - trace_events_enabled_count += state - trace_events_dstate[id];
>> >> - trace_events_dstate[id] = state;
>> >> + if (state) {
>> >> + trace_events_enabled_count++;
>> >> + trace_events_dstate[id] = 1;
>> >> + } else {
>> >> + trace_events_enabled_count--;
>>
>> > SHouldn't this be trace_events_enabled_count -= trace_events_dstate[id];
>> > as it is possible to call this method for a trace event that is a per-vcpu
>> > event
>>
>> The "stub" code will never have vCPUs around, it's used by qemu-img and the like
>> (any program without "target" code).
> I just picked the first example of that in this file - you've got the same
> pattern in the other 2 places you change
In the "control-target.c" file, there's two places where this pattern also
appears.
In trace_event_set_state_dynamic(), the pattern only appears on events that do
*not* have the "vcpu" property, and so the counter is always either 1 or 0.
In trace_event_set_state_dynamic_init() there's the "special" case where we
assume there won't be multiple enables of a single event with "vcpu" (as the
comment says); this is what let's us get rid of the dstate_init array.
What I just saw is wrong is that this code looses the ability to make
enable/disable operations idempotent. I'll send a v4 with that fixed.
Thanks,
Lluis
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2016-08-11 17:22 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-08-11 16:11 [Qemu-devel] [PATCH v3 0/2] trace: Simplify late initialization Lluís Vilanova
2016-08-11 16:11 ` [Qemu-devel] [PATCH v3 1/2] trace: Remove 'trace_events_dstate_init' Lluís Vilanova
2016-08-11 16:11 ` [Qemu-devel] [PATCH v3 2/2] trace: Avoid implicit bool->integer conversions Lluís Vilanova
2016-08-11 16:31 ` Daniel P. Berrange
2016-08-11 16:41 ` Lluís Vilanova
2016-08-11 16:51 ` Daniel P. Berrange
2016-08-11 17:22 ` Lluís Vilanova
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