Hello Stefan,
Thank you for reviewing my patch.
(2013/04/08 23:10), Stefan Hajnoczi wrote:
On Wed, Apr 03, 2013 at 03:30:58PM +0900, Eiichi Tsukata wrote:
diff --git a/scripts/tracetool/backend/ftrace.py
b/scripts/tracetool/backend/ftrace.py
new file mode 100644
index 0000000..e02f0ca
--- /dev/null
+++ b/scripts/tracetool/backend/ftrace.py
@@ -0,0 +1,53 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+"""
+Ftrace built-in backend.
+"""
+
+__author__ = "Eiichi Tsukata<eiichi.tsukata...@hitachi.com>"
+__copyright__ = "Copyright (C) 2013 Hitachi, Ltd."
+__license__ = "GPL version 2 or (at your option) any later version"
+
+__maintainer__ = "Stefan Hajnoczi"
+__email__ = "stefa...@linux.vnet.ibm.com"
My email is now stefa...@redhat.com. I can fix this up when merging the
patch.
I see, I'll fix it up.
+ out('static inline void trace_%(name)s(%(args)s)',
+ '{',
+ ' char ftrace_buf[MAX_TRACE_STRLEN];',
+ ' int unused __attribute__ ((unused));'
+ ' bool _state = trace_event_get_state(%(event_id)s);',
+ ' if (_state) {',
+ ' snprintf(ftrace_buf, MAX_TRACE_STRLEN,',
+ ' "%(name)s " %(fmt)s "\\n" %(argnames)s);',
+ ' unused = write(trace_marker_fd, ftrace_buf,',
+ ' MAX_TRACE_STRLEN);',
Looking at kernel/trace/trace.c:tracing_mark_write() the kernel will
memcpy() the full number of bytes we give.
You could use the snprintf(3) return value (number of characters
written, excluding NUL byte).
I think that would waste less trace buffer space.
Sounds good.
I'll use snprintf(3) return value in V2 patch and send it soon.
Eiichi
Stefan
.
