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[Qemu-devel] [PATCH v2 4/6] trace: remove global 'uint16 dstate[]' array
From: |
Daniel P. Berrange |
Subject: |
[Qemu-devel] [PATCH v2 4/6] trace: remove global 'uint16 dstate[]' array |
Date: |
Wed, 14 Sep 2016 18:08:40 +0100 |
Instead of having a global dstate array, declare a single
'uint16 TRACE_${EVENT_NAME}_DSTATE' variable for each
trace event. Record a pointer to this variable in the
TraceEvent struct too.
By turning trace_event_get_state_dynamic_by_id into a
macro, this still hits the fast path, and cache affinity
is ensured by declaring all the uint16 vars adjacent to
each other.
Signed-off-by: Daniel P. Berrange <address@hidden>
---
scripts/tracetool/format/events_c.py | 6 +++++-
scripts/tracetool/format/events_h.py | 3 +++
stubs/trace-control.c | 9 ++++-----
trace/control-internal.h | 14 ++++----------
trace/control-target.c | 20 ++++++++------------
trace/control.c | 11 ++---------
trace/event-internal.h | 6 ++++++
7 files changed, 32 insertions(+), 37 deletions(-)
diff --git a/scripts/tracetool/format/events_c.py
b/scripts/tracetool/format/events_c.py
index 4012063..a2f457f 100644
--- a/scripts/tracetool/format/events_c.py
+++ b/scripts/tracetool/format/events_c.py
@@ -25,6 +25,9 @@ def generate(events, backend):
'#include "trace/control.h"',
'')
+ for e in events:
+ out('uint16_t TRACE_%s_DSTATE;' % e.name.upper())
+
out('TraceEvent trace_events[TRACE_EVENT_COUNT] = {')
for e in events:
@@ -34,7 +37,8 @@ def generate(events, backend):
vcpu_id = "TRACE_VCPU_EVENT_COUNT"
out(' { .id = %(id)s, .vcpu_id = %(vcpu_id)s,'
' .name = \"%(name)s\",'
- ' .sstate = %(sstate)s },',
+ ' .sstate = %(sstate)s,',
+ ' .dstate = &%(id)s_DSTATE, }, ',
id = "TRACE_" + e.name.upper(),
vcpu_id = vcpu_id,
name = e.name,
diff --git a/scripts/tracetool/format/events_h.py
b/scripts/tracetool/format/events_h.py
index a9da60b..193b02c 100644
--- a/scripts/tracetool/format/events_h.py
+++ b/scripts/tracetool/format/events_h.py
@@ -32,6 +32,9 @@ def generate(events, backend):
out(' TRACE_EVENT_COUNT',
'} TraceEventID;')
+ for e in events:
+ out('extern uint16_t TRACE_%s_DSTATE;' % e.name.upper())
+
# per-vCPU event identifiers
out('typedef enum {')
diff --git a/stubs/trace-control.c b/stubs/trace-control.c
index 2dfcd9f..dd68f25 100644
--- a/stubs/trace-control.c
+++ b/stubs/trace-control.c
@@ -18,22 +18,21 @@ void trace_event_set_state_dynamic_init(TraceEvent *ev,
bool state)
void trace_event_set_state_dynamic(TraceEvent *ev, bool state)
{
- TraceEventID id;
bool state_pre;
assert(trace_event_get_state_static(ev));
- id = trace_event_get_id(ev);
+
/*
* We ignore the "vcpu" property here, since there's no target code. Then
* dstate can only be 1 or 0.
*/
- state_pre = trace_events_dstate[id];
+ state_pre = *(ev->dstate);
if (state_pre != state) {
if (state) {
trace_events_enabled_count++;
- trace_events_dstate[id] = 1;
+ *(ev->dstate) = 1;
} else {
trace_events_enabled_count--;
- trace_events_dstate[id] = 0;
+ *(ev->dstate) = 0;
}
}
}
diff --git a/trace/control-internal.h b/trace/control-internal.h
index 7f31e39..1446498 100644
--- a/trace/control-internal.h
+++ b/trace/control-internal.h
@@ -16,7 +16,6 @@
extern TraceEvent trace_events[];
-extern uint16_t trace_events_dstate[];
extern int trace_events_enabled_count;
@@ -54,18 +53,13 @@ static inline bool trace_event_get_state_static(TraceEvent
*ev)
return ev->sstate;
}
-static inline bool trace_event_get_state_dynamic_by_id(TraceEventID id)
-{
- /* it's on fast path, avoid consistency checks (asserts) */
- return unlikely(trace_events_enabled_count) && trace_events_dstate[id];
-}
+/* it's on fast path, avoid consistency checks (asserts) */
+#define trace_event_get_state_dynamic_by_id(id) \
+ (unlikely(trace_events_enabled_count) && id ## _DSTATE)
static inline bool trace_event_get_state_dynamic(TraceEvent *ev)
{
- TraceEventID id;
- assert(trace_event_get_state_static(ev));
- id = trace_event_get_id(ev);
- return trace_event_get_state_dynamic_by_id(id);
+ return unlikely(trace_events_enabled_count) && *ev->dstate;
}
static inline bool trace_event_get_vcpu_state_dynamic_by_vcpu_id(CPUState
*vcpu,
diff --git a/trace/control-target.c b/trace/control-target.c
index 72081e2..c69dda9 100644
--- a/trace/control-target.c
+++ b/trace/control-target.c
@@ -15,21 +15,20 @@
void trace_event_set_state_dynamic_init(TraceEvent *ev, bool state)
{
- TraceEventID id = trace_event_get_id(ev);
bool state_pre;
assert(trace_event_get_state_static(ev));
/*
* We ignore the "vcpu" property here, since no vCPUs have been created
* yet. Then dstate can only be 1 or 0.
*/
- state_pre = trace_events_dstate[id];
+ state_pre = *ev->dstate;
if (state_pre != state) {
if (state) {
trace_events_enabled_count++;
- trace_events_dstate[id] = 1;
+ *ev->dstate = 1;
} else {
trace_events_enabled_count--;
- trace_events_dstate[id] = 0;
+ *ev->dstate = 0;
}
}
}
@@ -44,15 +43,14 @@ void trace_event_set_state_dynamic(TraceEvent *ev, bool
state)
}
} else {
/* Without the "vcpu" property, dstate can only be 1 or 0 */
- TraceEventID id = trace_event_get_id(ev);
- bool state_pre = trace_events_dstate[id];
+ bool state_pre = *ev->dstate;
if (state_pre != state) {
if (state) {
trace_events_enabled_count++;
- trace_events_dstate[id] = 1;
+ *ev->dstate = 1;
} else {
trace_events_enabled_count--;
- trace_events_dstate[id] = 0;
+ *ev->dstate = 0;
}
}
}
@@ -61,23 +59,21 @@ void trace_event_set_state_dynamic(TraceEvent *ev, bool
state)
void trace_event_set_vcpu_state_dynamic(CPUState *vcpu,
TraceEvent *ev, bool state)
{
- TraceEventID id;
TraceEventVCPUID vcpu_id;
bool state_pre;
assert(trace_event_get_state_static(ev));
assert(trace_event_is_vcpu(ev));
- id = trace_event_get_id(ev);
vcpu_id = trace_event_get_vcpu_id(ev);
state_pre = test_bit(vcpu_id, vcpu->trace_dstate);
if (state_pre != state) {
if (state) {
trace_events_enabled_count++;
set_bit(vcpu_id, vcpu->trace_dstate);
- trace_events_dstate[id]++;
+ (*ev->dstate)++;
} else {
trace_events_enabled_count--;
clear_bit(vcpu_id, vcpu->trace_dstate);
- trace_events_dstate[id]--;
+ (*ev->dstate)--;
}
}
}
diff --git a/trace/control.c b/trace/control.c
index e9a64d0..c24b863 100644
--- a/trace/control.c
+++ b/trace/control.c
@@ -28,12 +28,6 @@
#include "monitor/monitor.h"
int trace_events_enabled_count;
-/*
- * Interpretation depends on wether the event has the 'vcpu' property:
- * - false: Boolean value indicating whether the event is active.
- * - true : Integral counting the number of vCPUs that have this event enabled.
- */
-uint16_t trace_events_dstate[TRACE_EVENT_COUNT];
QemuOptsList qemu_trace_opts = {
.name = "trace",
@@ -293,11 +287,10 @@ void trace_init_vcpu_events(void)
if (trace_event_is_vcpu(ev) &&
trace_event_get_state_static(ev) &&
trace_event_get_state_dynamic(ev)) {
- TraceEventID id = trace_event_get_id(ev);
/* check preconditions */
- assert(trace_events_dstate[id] == 1);
+ assert(*ev->dstate == 1);
/* disable early-init state ... */
- trace_events_dstate[id] = 0;
+ *ev->dstate = 0;
trace_events_enabled_count--;
/* ... and properly re-enable */
trace_event_set_state_dynamic(ev, true);
diff --git a/trace/event-internal.h b/trace/event-internal.h
index 074faf6..3b9ceb5 100644
--- a/trace/event-internal.h
+++ b/trace/event-internal.h
@@ -19,6 +19,11 @@
* @vcpu_id: Unique per-vCPU event identifier.
* @name: Event name.
* @sstate: Static tracing state.
+ * @dstate: Dynamic tracing state
+ *
+ * Interpretation of @dstate depends on wether the event has the 'vcpu'
property:
+ * - false: Boolean value indicating whether the event is active.
+ * - true : Integral counting the number of vCPUs that have this event enabled.
*
* Opaque generic description of a tracing event.
*/
@@ -27,6 +32,7 @@ typedef struct TraceEvent {
TraceEventVCPUID vcpu_id;
const char * name;
const bool sstate;
+ uint16_t *dstate;
} TraceEvent;
void trace_event_set_state_dynamic_init(TraceEvent *ev, bool state);
--
2.7.4
- [Qemu-devel] [PATCH v2 0/6] Prep changes for modular trace-events build, Daniel P. Berrange, 2016/09/14
- [Qemu-devel] [PATCH v2 1/6] trace: add trace event iterator APIs, Daniel P. Berrange, 2016/09/14
- [Qemu-devel] [PATCH v2 3/6] trace: remove some now unused functions, Daniel P. Berrange, 2016/09/14
- [Qemu-devel] [PATCH v2 2/6] trace: convert code to use event iterators, Daniel P. Berrange, 2016/09/14
- [Qemu-devel] [PATCH v2 4/6] trace: remove global 'uint16 dstate[]' array,
Daniel P. Berrange <=
- [Qemu-devel] [PATCH v2 6/6] trace: use -1 instead of TRACE_VCPU_EVENT_COUNT as magic value, Daniel P. Berrange, 2016/09/14
- [Qemu-devel] [PATCH v2 5/6] trace: remove use of event ID enums from APIs, Daniel P. Berrange, 2016/09/14
Re: [Qemu-devel] [PATCH v2 0/6] Prep changes for modular trace-events build, no-reply, 2016/09/14