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authorLluís <xscript@gmx.net>2011-08-31 20:31:45 +0200
committerStefan Hajnoczi <stefanha@linux.vnet.ibm.com>2011-09-01 10:34:54 +0100
commit03727e6a06087dc8f46d5674b4b29262bf7377a4 (patch)
treeaeae1754304b2e1ad7f0095d77385a18eb775697 /docs
parentdd215f646c72b4cf680097b13aeb8b0c589dceb2 (diff)
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>
Diffstat (limited to 'docs')
-rw-r--r--docs/tracing.txt11
1 files changed, 8 insertions, 3 deletions
diff --git a/docs/tracing.txt b/docs/tracing.txt
index 85793cf173..d1d4e8cba2 100644
--- a/docs/tracing.txt
+++ b/docs/tracing.txt
@@ -12,11 +12,16 @@ for debugging, profiling, and observing execution.
./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-*