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7cd5738d0d
Since 'perf probe' heavily depends on debuginfo, debuginfod gives us
many benefits on the 'perf probe' command on remote machine.
Especially, this will be helpful for the embedded devices which will not
have enough storage, or boot with a cross-build kernel whose source code
is in the host machine.
This will work as similar to commit c7a14fdcb3 ("perf build-ids:
Fall back to debuginfod query if debuginfo not found")
Tested with:
(host) $ cd PATH/TO/KBUILD/DIR/
(host) $ debuginfod -F .
...
(remote) # perf probe -L vfs_read
Failed to find the path for the kernel: No such file or directory
Error: Failed to show lines.
(remote) # export DEBUGINFOD_URLS="http://$HOST_IP:8002/"
(remote) # perf probe -L vfs_read
<vfs_read@...>
0 ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
{
2 ssize_t ret;
if (!(file->f_mode & FMODE_READ))
return -EBADF;
6 if (!(file->f_mode & FMODE_CAN_READ))
return -EINVAL;
8 if (unlikely(!access_ok(buf, count)))
return -EFAULT;
11 ret = rw_verify_area(READ, file, pos, count);
12 if (ret)
return ret;
if (count > MAX_RW_COUNT)
...
(remote) # perf probe -a "vfs_read count"
Added new event:
probe:vfs_read (on vfs_read with count)
(remote) # perf probe -l
probe:vfs_read (on vfs_read@ksrc/linux/fs/read_write.c with count)
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Frank Ch. Eigler <fche@redhat.com>
Cc: Aaron Merey <amerey@redhat.com>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Link: http://lore.kernel.org/lkml/160041610083.912668.13659563860278615846.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.