3 Commits

Author SHA1 Message Date
Ross Zwisler
07496eeab5 tools/virtio: use canonical ftrace path
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>
Message-Id: <20230215223350.2658616-6-zwisler@google.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com>
2023-06-09 12:08:08 -04:00
Ross Zwisler
9513c55ce3 tools/virtio: fix typo in README instructions
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 <zwisler@google.com>
Message-Id: <20230215223350.2658616-7-zwisler@google.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2023-04-04 11:01:58 -04:00
Yoshihiro YUNOMAE
108fc82596 tools: Add guest trace agent as a user tool
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 <yoshihiro.yunomae.ez@hitachi.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-28 15:05:13 +09:30