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
next prev parent reply other threads:[~2023-01-30 19:27 UTC|newest]
Thread overview: 24+ 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]
2023-02-01 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
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