mainlining shenanigans
63cd02d84b
Before this change, the '--graph-funcs', '--nograph-funcs' and
'--trace-funcs' options didn't work as expected when the <func> doesn't
exist. Because the kernel side hid possible errors.
$ sudo ./perf ftrace -a --graph-depth 1 --graph-funcs abcdefg
0) 0.140 us | rcu_all_qs();
3) 0.304 us | mutex_unlock();
0) 0.153 us | find_vma();
3) 0.088 us | __fsnotify_parent();
0) 6.145 us | handle_mm_fault();
3) 0.089 us | fsnotify();
3) 0.161 us | __sb_end_write();
3) 0.710 us | SyS_close();
3) 7.848 us | exit_to_usermode_loop();
On the example above, I specified the function filter 'abcdefg' but all
functions are enabled. The expected result is for all functions to be
filtered, since there is no such function ('abcdefg')
The original fix is to make the kernel support '\0' as end of string:
https://lkml.org/lkml/2018/1/16/116
But above fix cannot be compatible with old kernels. Then Namhyung Kim
suggest adding a space after function name.
This patch will append an '\n' when write tracing file. After this fix,
the perf will report correct error state. Also let it print an error if
reset_tracing_files() fails.
Committer testing:
Now it prints:
# perf ftrace -a --graph-depth 1 --graph-funcs abcdefg
failed to set tracing filters
#
And for an existing function:
# perf ftrace -a --graph-depth 1 --graph-funcs SyS_open
3) | SyS_open() {
3) ! 494.899 us | }
0) + 23.910 us | SyS_open();
1) + 17.115 us | SyS_open();
1) + 13.900 us | SyS_open();
------------------------------------------
3) qemu-sy-2817 => pickup-1290
------------------------------------------
3) + 20.021 us | SyS_open();
#
Signed-off-by: Changbin Du <changbin.du@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1519007609-14551-1-git-send-email-changbin.du@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.