[3/4] trace: document '-' syntax for disabling events

Message ID 1353071965-19804-4-git-send-email-stefanha@redhat.com
State New
Headers show

Commit Message

Stefan Hajnoczi Nov. 16, 2012, 1:19 p.m.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
 docs/tracing.txt | 4 ++++
 1 file changed, 4 insertions(+)


diff --git a/docs/tracing.txt b/docs/tracing.txt
index c541133..7901409 100644
--- a/docs/tracing.txt
+++ b/docs/tracing.txt
@@ -139,6 +139,10 @@  having a common prefix in a batch. For example, virtio-blk trace events could
 be enabled using:
   trace-event virtio_blk_* on
+If a line in the "-trace events=<file>" file begins with a '-', the trace event
+will be disabled instead of enabled.  This is useful when a wildcard was used
+to enable an entire family of events but one noisy event needs to be disabled.
 == Trace backends ==
 The "tracetool" script automates tedious trace event code generation and also