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From: "Michael S. Tsirkin" <mst@redhat.com>
To: Ross Zwisler <zwisler@chromium.org>
Cc: linux-kernel@vger.kernel.org, Ross Zwisler <zwisler@google.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	linux-trace-kernel@vger.kernel.org,
	Jason Wang <jasowang@redhat.com>,
	virtualization@lists.linux-foundation.org
Subject: Re: [PATCH 7/9] tools/virtio: use canonical ftrace path
Date: Mon, 30 Jan 2023 14:26:43 -0500	[thread overview]
Message-ID: <20230130142616-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20230130181915.1113313-8-zwisler@google.com>

On Mon, Jan 30, 2023 at 11:19:13AM -0700, Ross Zwisler wrote:
> The canonical location for the tracefs filesystem is at /sys/kernel/tracing.
> 
> But, from Documentation/trace/ftrace.rst:
> 
>   Before 4.1, all ftrace tracing control files were within the debugfs
>   file system, which is typically located at /sys/kernel/debug/tracing.
>   For backward compatibility, when mounting the debugfs file system,
>   the tracefs file system will be automatically mounted at:
> 
>   /sys/kernel/debug/tracing
> 
> A few spots in tools/virtio still refer to this older debugfs
> path, so let's update them to avoid confusion.
> 
> Signed-off-by: Ross Zwisler <zwisler@google.com>
> ---
>  tools/virtio/virtio-trace/README        | 2 +-
>  tools/virtio/virtio-trace/trace-agent.c | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/virtio/virtio-trace/README b/tools/virtio/virtio-trace/README
> index b64845b823ab..cea29a2a4c0a 100644
> --- a/tools/virtio/virtio-trace/README
> +++ b/tools/virtio/virtio-trace/README
> @@ -95,7 +95,7 @@ Run
>  
>  1) Enable ftrace in the guest
>   <Example>
> -	# echo 1 > /sys/kernel/debug/tracing/events/sched/enable
> +	# echo 1 > /sys/kernel/tracing/events/sched/enable
>  
>  2) Run trace agent in the guest
>   This agent must be operated as root.
> diff --git a/tools/virtio/virtio-trace/trace-agent.c b/tools/virtio/virtio-trace/trace-agent.c
> index cdfe77c2b4c8..805942d02e9f 100644
> --- a/tools/virtio/virtio-trace/trace-agent.c
> +++ b/tools/virtio/virtio-trace/trace-agent.c
> @@ -19,7 +19,7 @@
>  #define PIPE_MIN_SIZE		(PAGE_SIZE*PIPE_DEF_BUFS)
>  #define PIPE_MAX_SIZE		(1024*1024)
>  #define READ_PATH_FMT	\
> -		"/sys/kernel/debug/tracing/per_cpu/cpu%d/trace_pipe_raw"
> +		"/sys/kernel/tracing/per_cpu/cpu%d/trace_pipe_raw"

Should we try both old and new path then?

>  #define WRITE_PATH_FMT		"/dev/virtio-ports/trace-path-cpu%d"
>  #define CTL_PATH		"/dev/virtio-ports/agent-ctl-path"
>  
> -- 
> 2.39.1.456.gfc5497dd1b-goog


WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Ross Zwisler <zwisler@chromium.org>
Cc: Ross Zwisler <zwisler@google.com>,
	linux-kernel@vger.kernel.org,
	Steven Rostedt <rostedt@goodmis.org>,
	virtualization@lists.linux-foundation.org,
	linux-trace-kernel@vger.kernel.org
Subject: Re: [PATCH 7/9] tools/virtio: use canonical ftrace path
Date: Mon, 30 Jan 2023 14:26:43 -0500	[thread overview]
Message-ID: <20230130142616-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20230130181915.1113313-8-zwisler@google.com>

On Mon, Jan 30, 2023 at 11:19:13AM -0700, Ross Zwisler wrote:
> The canonical location for the tracefs filesystem is at /sys/kernel/tracing.
> 
> But, from Documentation/trace/ftrace.rst:
> 
>   Before 4.1, all ftrace tracing control files were within the debugfs
>   file system, which is typically located at /sys/kernel/debug/tracing.
>   For backward compatibility, when mounting the debugfs file system,
>   the tracefs file system will be automatically mounted at:
> 
>   /sys/kernel/debug/tracing
> 
> A few spots in tools/virtio still refer to this older debugfs
> path, so let's update them to avoid confusion.
> 
> Signed-off-by: Ross Zwisler <zwisler@google.com>
> ---
>  tools/virtio/virtio-trace/README        | 2 +-
>  tools/virtio/virtio-trace/trace-agent.c | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/virtio/virtio-trace/README b/tools/virtio/virtio-trace/README
> index b64845b823ab..cea29a2a4c0a 100644
> --- a/tools/virtio/virtio-trace/README
> +++ b/tools/virtio/virtio-trace/README
> @@ -95,7 +95,7 @@ Run
>  
>  1) Enable ftrace in the guest
>   <Example>
> -	# echo 1 > /sys/kernel/debug/tracing/events/sched/enable
> +	# echo 1 > /sys/kernel/tracing/events/sched/enable
>  
>  2) Run trace agent in the guest
>   This agent must be operated as root.
> diff --git a/tools/virtio/virtio-trace/trace-agent.c b/tools/virtio/virtio-trace/trace-agent.c
> index cdfe77c2b4c8..805942d02e9f 100644
> --- a/tools/virtio/virtio-trace/trace-agent.c
> +++ b/tools/virtio/virtio-trace/trace-agent.c
> @@ -19,7 +19,7 @@
>  #define PIPE_MIN_SIZE		(PAGE_SIZE*PIPE_DEF_BUFS)
>  #define PIPE_MAX_SIZE		(1024*1024)
>  #define READ_PATH_FMT	\
> -		"/sys/kernel/debug/tracing/per_cpu/cpu%d/trace_pipe_raw"
> +		"/sys/kernel/tracing/per_cpu/cpu%d/trace_pipe_raw"

Should we try both old and new path then?

>  #define WRITE_PATH_FMT		"/dev/virtio-ports/trace-path-cpu%d"
>  #define CTL_PATH		"/dev/virtio-ports/agent-ctl-path"
>  
> -- 
> 2.39.1.456.gfc5497dd1b-goog

_______________________________________________
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Virtualization@lists.linux-foundation.org
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  reply	other threads:[~2023-01-30 19:27 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-30 18:19 [PATCH 0/9] use canonical ftrace path whenever possible Ross Zwisler
2023-01-30 18:19 ` [PATCH 1/9] tracing: always use canonical ftrace path Ross Zwisler
2023-01-30 18:19 ` [PATCH 2/9] bpf: " Ross Zwisler
2023-01-30 18:19 ` [PATCH 3/9] selftests/bpf: " Ross Zwisler
2023-01-30 19:52   ` Alexei Starovoitov
2023-01-30 19:59     ` Steven Rostedt
2023-01-30 20:03       ` Alexei Starovoitov
2023-01-30 23:34         ` Steven Rostedt
2023-01-31  0:53           ` Alexei Starovoitov
2023-01-31 19:50             ` Steven Rostedt
2023-01-31 23:25               ` Alexei Starovoitov
2023-02-01  0:05                 ` Ross Zwisler
2023-01-30 18:19 ` [PATCH 4/9] perf docs: " Ross Zwisler
2023-02-02  1:24   ` Arnaldo Carvalho de Melo
2023-01-30 18:19 ` [PATCH 5/9] tools/power: " Ross Zwisler
2023-02-02 14:47   ` Rafael J. Wysocki
2023-01-30 18:19 ` [PATCH 6/9] selftests: " Ross Zwisler
2023-01-30 18:19 ` [PATCH 7/9] tools/virtio: " Ross Zwisler
2023-01-30 19:26   ` Michael S. Tsirkin [this message]
2023-01-30 19:26     ` Michael S. Tsirkin
2023-02-01 22:07     ` Ross Zwisler
2023-01-30 18:19 ` [PATCH 8/9] leaking_addresses: also skip " Ross Zwisler
2023-01-30 19:34   ` Tycho Andersen
2023-01-30 18:19 ` [PATCH 9/9] tools/kvm_stat: use " Ross Zwisler
2023-01-30 19:26 ` [PATCH 0/9] use canonical ftrace path whenever possible Michael S. Tsirkin
2023-01-30 19:26   ` Michael S. Tsirkin

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