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[Qemu-devel] [PULL 02/18] trace: add tracetool simpletrace_stap format
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PULL 02/18] trace: add tracetool simpletrace_stap format |
Date: |
Tue, 12 Aug 2014 14:37:39 +0100 |
This new tracetool "format" generates a SystemTap .stp file that outputs
simpletrace binary trace data.
In contrast to simpletrace or ftrace, SystemTap does not define its own
trace format. All output from SystemTap is generated by .stp files.
This patch lets us generate a .stp file that outputs in the simpletrace
binary format.
This makes it possible to reuse simpletrace.py to analyze traces
recorded using SystemTap. The simpletrace binary format is especially
useful for long-running traces like flight-recorder mode where string
formatting can be expensive.
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
scripts/tracetool/format/simpletrace_stap.py | 71 ++++++++++++++++++++++++++++
1 file changed, 71 insertions(+)
create mode 100644 scripts/tracetool/format/simpletrace_stap.py
diff --git a/scripts/tracetool/format/simpletrace_stap.py
b/scripts/tracetool/format/simpletrace_stap.py
new file mode 100644
index 0000000..7e44bc1
--- /dev/null
+++ b/scripts/tracetool/format/simpletrace_stap.py
@@ -0,0 +1,71 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+"""
+Generate .stp file that outputs simpletrace binary traces (DTrace with
SystemTAP only).
+"""
+
+__author__ = "Stefan Hajnoczi <redhat.com>"
+__copyright__ = "Copyright (C) 2014, Red Hat, Inc."
+__license__ = "GPL version 2 or (at your option) any later version"
+
+__maintainer__ = "Stefan Hajnoczi"
+__email__ = "address@hidden"
+
+
+from tracetool import out
+from tracetool.backend.dtrace import binary, probeprefix
+from tracetool.backend.simple import is_string
+from tracetool.format.stap import stap_escape
+
+
+def generate(events, backend):
+ out('/* This file is autogenerated by tracetool, do not edit. */',
+ '')
+
+ for event_id, e in enumerate(events):
+ if 'disable' in e.properties:
+ continue
+
+ out('probe %(probeprefix)s.simpletrace.%(name)s =
%(probeprefix)s.%(name)s ?',
+ '{',
+ probeprefix=probeprefix(),
+ name=e.name)
+
+ # Calculate record size
+ sizes = ['24'] # sizeof(TraceRecord)
+ for type_, name in e.args:
+ name = stap_escape(name)
+ if is_string(type_):
+ out(' try {',
+ ' arg%(name)s_str = %(name)s ?
user_string_n(%(name)s, 512) : "<null>"',
+ ' } catch {}',
+ ' arg%(name)s_len = strlen(arg%(name)s_str)',
+ name=name)
+ sizes.append('4 + arg%s_len' % name)
+ else:
+ sizes.append('8')
+ sizestr = ' + '.join(sizes)
+
+ # Generate format string and value pairs for record header and
arguments
+ fields = [('8b', str(event_id)),
+ ('8b', 'gettimeofday_ns()'),
+ ('4b', sizestr),
+ ('4b', 'pid()')]
+ for type_, name in e.args:
+ name = stap_escape(name)
+ if is_string(type_):
+ fields.extend([('4b', 'arg%s_len' % name),
+ ('.*s', 'arg%s_len, arg%s_str' % (name, name))])
+ else:
+ fields.append(('8b', name))
+
+ # Emit the entire record in a single SystemTap printf()
+ fmt_str = '%'.join(fmt for fmt, _ in fields)
+ arg_str = ', '.join(arg for _, arg in fields)
+ out(' printf("%%%(fmt_str)s", %(arg_str)s)',
+ fmt_str=fmt_str, arg_str=arg_str)
+
+ out('}')
+
+ out()
--
1.9.3
- [Qemu-devel] [PULL 00/18] Tracing patches, Stefan Hajnoczi, 2014/08/12
- [Qemu-devel] [PULL 02/18] trace: add tracetool simpletrace_stap format,
Stefan Hajnoczi <=
- [Qemu-devel] [PULL 01/18] trace: extract stap_escape() function for reuse, Stefan Hajnoczi, 2014/08/12
- [Qemu-devel] [PULL 04/18] trace: install simpletrace SystemTap tapset, Stefan Hajnoczi, 2014/08/12
- [Qemu-devel] [PULL 03/18] simpletrace: add simpletrace.py --no-header option, Stefan Hajnoczi, 2014/08/12
- [Qemu-devel] [PULL 06/18] trace: [tcg] Argument type transformation rules, Stefan Hajnoczi, 2014/08/12
- [Qemu-devel] [PULL 05/18] trace: [tcg] Add documentation, Stefan Hajnoczi, 2014/08/12
- [Qemu-devel] [PULL 07/18] trace: [tcg] Argument type transformation machinery, Stefan Hajnoczi, 2014/08/12
- [Qemu-devel] [PULL 08/18] trace: [tcg] Add 'tcg' event property, Stefan Hajnoczi, 2014/08/12
- [Qemu-devel] [PULL 10/18] trace: [tcg] Define TCG tracing helper routines, Stefan Hajnoczi, 2014/08/12
- [Qemu-devel] [PULL 09/18] trace: [tcg] Declare TCG tracing helper routines, Stefan Hajnoczi, 2014/08/12
- [Qemu-devel] [PULL 11/18] trace: [tcg] Define TCG tracing helper routine wrappers, Stefan Hajnoczi, 2014/08/12