Re: [RFC][PATCH] tracing: Replace '-' with '_' in event system names

From: Xenia Ragiadakou
Date: Wed Apr 01 2015 - 05:20:44 EST

On 01/04/2015 06:18 ÏÎ, Steven Rostedt wrote:
There's a change I want to make to the tracing infrastructure that may
require TRACE_SYSTEM be a valid variable name. As '-' can not be used
in a variable, and I found only three cases that it is a TRACE_SYSTEM
name, I want to ask those that are responsible if it is OK to change

The three systems are:

#define TRACE_SYSTEM kvm-s390
#define TRACE_SYSTEM xhci-hcd
#define TRACE_SYSTEM intel-sst

I want to replace the '-' with '_'. But this will have a user space
visible affect, which is why I'm inquiring with you. If this will break
any scripts or annoy any users that you know of, I'll need to make a
work around (which would not be hard to do). But if I don't need to do
that, I prefer to just use TRACE_SYSTEM as is.

I'll just do the work around if there is any user space tool that you
know of that will break with this change.

The effect is that the directories in /sys/kernel/debug/tracing/events/
will be different. That is,


will become


And the same for the other two. Is this a problem?


-- Steve

Tentatively-signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
arch/s390/kvm/trace-s390.h | 2 +-
drivers/usb/host/xhci-trace.h | 2 +-
include/trace/events/intel-sst.h | 2 +-
3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/s390/kvm/trace-s390.h b/arch/s390/kvm/trace-s390.h
index 653a7ec09ef5..bf02effdf535 100644
--- a/arch/s390/kvm/trace-s390.h
+++ b/arch/s390/kvm/trace-s390.h
@@ -4,7 +4,7 @@
#include <linux/tracepoint.h>

-#define TRACE_SYSTEM kvm-s390
+#define TRACE_SYSTEM kvm_s390
#define TRACE_INCLUDE_FILE trace-s390
diff --git a/drivers/usb/host/xhci-trace.h b/drivers/usb/host/xhci-trace.h
index dde3959b7a33..b610374b6f36 100644
--- a/drivers/usb/host/xhci-trace.h
+++ b/drivers/usb/host/xhci-trace.h
@@ -12,7 +12,7 @@

-#define TRACE_SYSTEM xhci-hcd
+#define TRACE_SYSTEM xhci_hcd

#if !defined(__XHCI_TRACE_H) || defined(TRACE_HEADER_MULTI_READ)
#define __XHCI_TRACE_H
diff --git a/include/trace/events/intel-sst.h b/include/trace/events/intel-sst.h
index 76c72d3f1902..11bb4ca0fac7 100644
--- a/include/trace/events/intel-sst.h
+++ b/include/trace/events/intel-sst.h
@@ -1,5 +1,5 @@
-#define TRACE_SYSTEM intel-sst
+#define TRACE_SYSTEM intel_sst

#if !defined(_TRACE_INTEL_SST_H) || defined(TRACE_HEADER_MULTI_READ)

The change affects the trace-cmd plugin for xhci, but I can fix that, no problem.

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