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

[Xenia Ragiadakou]

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
> them?
>
> 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,
>
>   /sys/kernel/debug/tracing/events/kvm-s390/
>
> will become
>
>   /sys/kernel/debug/tracing/events/kvm_s390/
>
> And the same for the other two. Is this a problem?
>
> Thanks!
>
> -- 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>
>
>   #undef TRACE_SYSTEM
> -#define TRACE_SYSTEM kvm-s390
> +#define TRACE_SYSTEM kvm_s390
>   #define TRACE_INCLUDE_PATH .
>   #undef TRACE_INCLUDE_FILE
>   #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 @@
>    */
>
>   #undef TRACE_SYSTEM
> -#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 @@
>   #undef TRACE_SYSTEM
> -#define TRACE_SYSTEM intel-sst
> +#define TRACE_SYSTEM intel_sst
>
>   #if !defined(_TRACE_INTEL_SST_H) || defined(TRACE_HEADER_MULTI_READ)
>   #define _TRACE_INTEL_SST_H


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

regards,
Xenia
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