trace: [simple] disable all trace points by default
Note that this refers to the backend-specific state (whether the output must be
generated), not the event "disabled" property (which always uses the "nop"
backend).
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
diff --git a/docs/tracing.txt b/docs/tracing.txt
index 85793cf..d1d4e8c 100644
--- a/docs/tracing.txt
+++ b/docs/tracing.txt
@@ -12,11 +12,16 @@
./configure --trace-backend=simple
make
-2. Run the virtual machine to produce a trace file:
+2. Create a file with the events you want to trace:
- qemu ... # your normal QEMU invocation
+ echo bdrv_aio_readv > /tmp/events
+ echo bdrv_aio_writev >> /tmp/events
-3. Pretty-print the binary trace file:
+3. Run the virtual machine to produce a trace file:
+
+ qemu -trace events=/tmp/events ... # your normal QEMU invocation
+
+4. Pretty-print the binary trace file:
./simpletrace.py trace-events trace-*
