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[Qemu-devel] [PATCH 04/14] trace: Support disabled events in trace-event
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PATCH 04/14] trace: Support disabled events in trace-events |
Date: |
Mon, 6 Sep 2010 16:14:01 +0100 |
Sometimes it is useful to disable a trace event. Removing the event
from trace-events is not enough since source code will call the
trace_*() function for the event.
This patch makes it easy to build without specific trace events by
marking them disabled in trace-events:
disable multiwrite_cb(void *mcb, int ret) "mcb %p ret %d"
This builds without the multiwrite_cb trace event.
Signed-off-by: Stefan Hajnoczi <address@hidden>
trace: Allow bulk enabling/disabling of trace events at compile time
For 'simple' trace backend, allow bulk enabling/disabling of trace
events at compile time. Trace events that are preceded by 'disable'
keyword are compiled in, but turned off by default. These can
individually be turned on using the monitor. All other trace events are
enabled by default.
TODO :
This could be enhanced when the trace-event namespace is partitioned into a
group and an ID within that group. In such a case, marking a group as enabled
would automatically enable all trace-events listed under it.
Signed-off-by: Prerna Saxena <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
trace-events | 7 ++++++-
tracetool | 44 +++++++++++++++++++++++++++++++++++++++-----
2 files changed, 45 insertions(+), 6 deletions(-)
diff --git a/trace-events b/trace-events
index a37d3cc..2a986ec 100644
--- a/trace-events
+++ b/trace-events
@@ -12,10 +12,15 @@
#
# Format of a trace event:
#
-# <name>(<type1> <arg1>[, <type2> <arg2>] ...) "<format-string>"
+# [disable] <name>(<type1> <arg1>[, <type2> <arg2>] ...) "<format-string>"
#
# Example: qemu_malloc(size_t size) "size %zu"
#
+# The "disable" keyword will build without the trace event.
+# In case of 'simple' trace backend, it will allow the trace event to be
+# compiled, but this would be turned off by default. It can be toggled on via
+# the monitor.
+#
# The <name> must be a valid as a C function name.
#
# Types should be standard C types. Use void * for pointers because the trace
diff --git a/tracetool b/tracetool
index 2e2e37d..8aeac48 100755
--- a/tracetool
+++ b/tracetool
@@ -87,6 +87,20 @@ get_fmt()
echo "$fmt"
}
+# Get the state of a trace event
+get_state()
+{
+ local str disable state
+ str=$(get_name "$1")
+ disable=${str##disable }
+ if [ "$disable" = "$str" ] ; then
+ state=1
+ else
+ state=0
+ fi
+ echo "$state"
+}
+
linetoh_begin_nop()
{
return
@@ -146,10 +160,14 @@ cast_args_to_uint64_t()
linetoh_simple()
{
- local name args argc trace_args
+ local name args argc trace_args state
name=$(get_name "$1")
args=$(get_args "$1")
argc=$(get_argc "$1")
+ state=$(get_state "$1")
+ if [ "$state" = "0" ]; then
+ name=${name##disable }
+ fi
trace_args="$simple_event_num"
if [ "$argc" -gt 0 ]
@@ -188,10 +206,14 @@ EOF
linetoc_simple()
{
- local name
+ local name state
name=$(get_name "$1")
+ state=$(get_state "$1")
+ if [ "$state" = "0" ] ; then
+ name=${name##disable }
+ fi
cat <<EOF
-{.tp_name = "$name", .state=0},
+{.tp_name = "$name", .state=$state},
EOF
simple_event_num=$((simple_event_num + 1))
}
@@ -206,7 +228,7 @@ EOF
# Process stdin by calling begin, line, and end functions for the backend
convert()
{
- local begin process_line end
+ local begin process_line end str disable
begin="lineto$1_begin_$backend"
process_line="lineto$1_$backend"
end="lineto$1_end_$backend"
@@ -218,8 +240,20 @@ convert()
str=${str%%#*}
test -z "$str" && continue
+ # Process the line. The nop backend handles disabled lines.
+ disable=${str%%disable *}
echo
- "$process_line" "$str"
+ if test -z "$disable"; then
+ # Pass the disabled state as an arg to lineto$1_simple().
+ # For all other cases, call lineto$1_nop()
+ if [ $backend = "simple" ]; then
+ "$process_line" "$str"
+ else
+ "lineto$1_nop" "${str##disable }"
+ fi
+ else
+ "$process_line" "$str"
+ fi
done
echo
--
1.7.1
- [Qemu-devel] [PATCH v3 00/14] trace: Add static tracing to QEMU, Stefan Hajnoczi, 2010/09/06
- [Qemu-devel] [PATCH 14/14] trace: Trace entry point of balloon request handler, Stefan Hajnoczi, 2010/09/06
- [Qemu-devel] [PATCH 05/14] trace: Specify trace file name, Stefan Hajnoczi, 2010/09/06
- [Qemu-devel] [PATCH 08/14] trace: Add LTTng Userspace Tracer backend, Stefan Hajnoczi, 2010/09/06
- [Qemu-devel] [PATCH 10/14] trace: Trace qemu_malloc() and qemu_vmalloc(), Stefan Hajnoczi, 2010/09/06
- [Qemu-devel] [PATCH 06/14] trace: Add trace-file command to open/close/flush trace file, Stefan Hajnoczi, 2010/09/06
- [Qemu-devel] [PATCH 03/14] trace: Support for dynamically enabling/disabling trace events, Stefan Hajnoczi, 2010/09/06
- [Qemu-devel] [PATCH 13/14] trace: Trace port IO, Stefan Hajnoczi, 2010/09/06
- [Qemu-devel] [PATCH 04/14] trace: Support disabled events in trace-events,
Stefan Hajnoczi <=
- [Qemu-devel] [PATCH 07/14] trace: Add trace file name command-line option, Stefan Hajnoczi, 2010/09/06
- [Qemu-devel] [PATCH 02/14] trace: Add simple built-in tracing backend, Stefan Hajnoczi, 2010/09/06
- [Qemu-devel] [PATCH 01/14] trace: Add trace-events file for declaring trace events, Stefan Hajnoczi, 2010/09/06
- [Qemu-devel] [PATCH 12/14] trace: Trace virtqueue operations, Stefan Hajnoczi, 2010/09/06
- [Qemu-devel] [PATCH 11/14] trace: Trace virtio-blk, multiwrite, and paio_submit, Stefan Hajnoczi, 2010/09/06
- [Qemu-devel] [PATCH 09/14] trace: Add user documentation, Stefan Hajnoczi, 2010/09/06
- Re: [Qemu-devel] [PATCH v3 00/14] trace: Add static tracing to QEMU, Daniel P. Berrange, 2010/09/06