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authorStefan Hajnoczi <stefanha@redhat.com>2014-01-15 11:10:30 +0800
committerStefan Hajnoczi <stefanha@redhat.com>2014-01-27 15:49:39 +0100
commit736ec1677f1ae7e64f2f3436ca3775c48f79678c (patch)
tree48db2dfcfc0a028a2a427b5b9c537c4a389aa705 /scripts
parent05735a2a9cf37f5dc11ece998906431dda707258 (diff)
trace: fix simple trace "disable" keyword
The trace-events "disable" keyword turns an event into a nop at compile-time. This is important for high-frequency events that can impact performance. The "disable" keyword is currently broken in the simple trace backend. This patch fixes the problem as follows: Trace events are identified by their TraceEventID number. When events are disabled there are two options for assigning TraceEventID numbers: 1. Skip disabled events and don't assign them a number. 2. Assign numbers for all events regardless of the disabled keyword. The simple trace backend and its binary file format uses approach #1. The tracetool infrastructure has been using approach #2 for a while. The result is that the numbers used in simple trace files do not correspond with TraceEventIDs. In trace/simple.c we assumed that they are identical and therefore emitted bogus numbers. This patch fixes the bug by using TraceEventID for trace_event_id() while sticking to approach #1 for simple trace file numbers. This preserves simple trace file format compatibility. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'scripts')
-rw-r--r--scripts/tracetool/backend/simple.py3
1 files changed, 2 insertions, 1 deletions
diff --git a/scripts/tracetool/backend/simple.py b/scripts/tracetool/backend/simple.py
index 30faac93c8..3dde372e46 100644
--- a/scripts/tracetool/backend/simple.py
+++ b/scripts/tracetool/backend/simple.py
@@ -56,7 +56,7 @@ def c(events):
out('',
- ' TraceEvent *eventp = trace_event_id(%(event_id)s);',
+ ' TraceEvent *eventp = trace_event_id(%(event_enum)s);',
' bool _state = trace_event_get_state_dynamic(eventp);',
' if (!_state) {',
' return;',
@@ -65,6 +65,7 @@ def c(events):
' if (trace_record_start(&rec, %(event_id)s, %(size_str)s)) {',
' return; /* Trace Buffer Full, Event Dropped ! */',
' }',
+ event_enum = 'TRACE_' + event.name.upper(),
event_id = num,
size_str = sizestr,
)