Thread (29 messages) 29 messages, 4 authors, 2015-01-21

Re: [RFC PATCH 3/8] perf probe: Improve detection of file/function name in the probe pattern

From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2014-12-10 10:00:13
Also in: lkml

On Tue, 2014-12-09 at 23:04 +0530, Naveen N. Rao wrote:
quoted hunk ↗ jump to hunk
Currently, perf probe considers patterns including a '.' to be a file.
However, this causes problems on powerpc ABIv1 where all functions have
a leading '.':

  $ perf probe -F | grep schedule_timeout_interruptible
  .schedule_timeout_interruptible
  $ perf probe .schedule_timeout_interruptible
  Semantic error :File always requires line number or lazy pattern.
    Error: Command Parse Error.

Fix this by checking the probe pattern in more detail.

Signed-off-by: Naveen N. Rao <redacted>
---
 tools/perf/util/probe-event.c | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index c150ca4..c7e01ef 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -999,6 +999,24 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
 		arg = tmp;
 	}
 
+	/*
+	 * Check arg is function or file name and copy it.
+	 *
+	 * We consider arg to be a file spec if and only if it satisfies
+	 * all of the below criteria::
+	 * - it does not include any of "+@%",
+	 * - it includes one of ":;", and
+	 * - it has a period '.' in the name.
I don't think we need to be this elaborate.

AFAIK there are no source files in the kernel that start with '.'

So if the arg starts with '.' it must be a function?

cheers
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