kernel/linux.git/tools/virtio/virtio-trace/README, branch linux-7.1.y

tools/virtio: use canonical ftrace path

2023-06-09T16:08:08+00:00

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 Message-Id: <20230215223350.2658616-6-zwisler@google.com> Signed-off-by: Michael S. Tsirkin Reviewed-by: Mukesh Ojha

tools/virtio: fix typo in README instructions

2023-04-04T15:01:58+00:00

We need to have a unique chardev for each data path, else the chardevs will collide and qemu will die with this message: qemu-system-x86_64: -device virtserialport,bus=virtio-serial0.0,nr=2,chardev=charchannel0, id=channel1,name=trace-path-cpu0: Property 'virtserialport.chardev' can't take value 'charchannel0': Device 'charchannel0' is in use Signed-off-by: Ross Zwisler Message-Id: <20230215223350.2658616-7-zwisler@google.com> Signed-off-by: Michael S. Tsirkin

tools: Add guest trace agent as a user tool

2012-09-28T05:35:13+00:00

This patch adds a user tool, "trace agent" for sending trace data of a guest to a Host in low overhead. This agent has the following functions: - splice a page of ring-buffer to read_pipe without memory copying - splice the page from write_pipe to virtio-console without memory copying - write trace data to stdout by using -o option - controlled by start/stop orders from a Host Changes in v2: - Cleanup (change fprintf() to pr_err() and an include guard) Signed-off-by: Yoshihiro YUNOMAE Acked-by: Amit Shah Signed-off-by: Rusty Russell