path: root/trace/control.c
diff options
authorLluís Vilanova <vilanova@ac.upc.edu>2017-07-04 10:34:19 +0200
committerStefan Hajnoczi <stefanha@redhat.com>2017-07-17 13:10:45 +0100
commitd01c05c955f7736952c13d85edaae0b262b7a0a3 (patch)
tree2f0f246640d0c12e7d762f776fa1c90200c9e85e /trace/control.c
parent4871b51b9241b10f4fd8e04bbb21577886795e25 (diff)
trace: Allocate cpu->trace_dstate in place
There's little point in dynamically allocating the bitmap if we know at compile-time the max number of events we want to support. Thus, make room in the struct for the bitmap, which will make things easier later: this paves the way for upcoming changes, in which we'll use a u32 to fully capture cpu->trace_dstate. This change also increases performance by saving a dereference and improving locality--note that this is important since upcoming work makes reading this bitmap fairly common. Signed-off-by: Emilio G. Cota <cota@braap.org> Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu> Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu> Message-id: 149915725977.6295.15069969323605305641.stgit@frigg.lan Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'trace/control.c')
1 files changed, 8 insertions, 1 deletions
diff --git a/trace/control.c b/trace/control.c
index f5fb11d280..82d8989c4d 100644
--- a/trace/control.c
+++ b/trace/control.c
@@ -65,8 +65,15 @@ void trace_event_register_group(TraceEvent **events)
size_t i;
for (i = 0; events[i] != NULL; i++) {
events[i]->id = next_id++;
- if (events[i]->vcpu_id != TRACE_VCPU_EVENT_NONE) {
+ if (events[i]->vcpu_id == TRACE_VCPU_EVENT_NONE) {
+ continue;
+ }
+ if (likely(next_vcpu_id < CPU_TRACE_DSTATE_MAX_EVENTS)) {
events[i]->vcpu_id = next_vcpu_id++;
+ } else {
+ error_report("WARNING: too many vcpu trace events; dropping '%s'",
+ events[i]->name);
event_groups = g_renew(TraceEventGroup, event_groups, nevent_groups + 1);