This is a partial revert of commit
7f1b588f20d027730676e627713ae3bbf6baab04 ("trace: emit name <-> ID
mapping in simpletrace header"), which broke the SystemTap flight
recorder because event mapping records may not be present in the ring
buffer when the trace is analyzed.  This means simpletrace.py
--no-header does not know the event ID mapping needed to pretty-print
the trace.
Instead of numbering events dynamically, use a static event ID mapping
as dictated by the event order in the trace-events-all file.
The simpletrace.py script also uses trace-events-all so the next patch
will fix the simpletrace.py --no-header option to take advantage of this
knowledge.
Cc: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170815084430.7128-2-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
		
	
			
		
			
				
	
	
		
			74 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			74 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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"""
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Generate .stp file that outputs simpletrace binary traces (DTrace with SystemTAP only).
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"""
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__author__     = "Stefan Hajnoczi <redhat.com>"
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__copyright__  = "Copyright (C) 2014, Red Hat, Inc."
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__license__    = "GPL version 2 or (at your option) any later version"
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__maintainer__ = "Stefan Hajnoczi"
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__email__      = "stefanha@redhat.com"
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from tracetool import out
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from tracetool.backend.dtrace import binary, probeprefix
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from tracetool.backend.simple import is_string
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from tracetool.format.stap import stap_escape
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def global_var_name(name):
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    return probeprefix().replace(".", "_") + "_" + name
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def generate(events, backend, group):
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    out('/* This file is autogenerated by tracetool, do not edit. */',
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        '')
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    for event_id, e in enumerate(events):
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        if 'disable' in e.properties:
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            continue
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        out('probe %(probeprefix)s.simpletrace.%(name)s = %(probeprefix)s.%(name)s ?',
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            '{',
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            probeprefix=probeprefix(),
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            name=e.name)
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        # Calculate record size
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        sizes = ['24'] # sizeof(TraceRecord)
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        for type_, name in e.args:
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            name = stap_escape(name)
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            if is_string(type_):
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                out('    try {',
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                    '        arg%(name)s_str = %(name)s ? user_string_n(%(name)s, 512) : "<null>"',
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                    '    } catch {}',
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                    '    arg%(name)s_len = strlen(arg%(name)s_str)',
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                    name=name)
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                sizes.append('4 + arg%s_len' % name)
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            else:
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                sizes.append('8')
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        sizestr = ' + '.join(sizes)
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        # Generate format string and value pairs for record header and arguments
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        fields = [('8b', str(event_id)),
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                  ('8b', 'gettimeofday_ns()'),
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                  ('4b', sizestr),
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                  ('4b', 'pid()')]
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        for type_, name in e.args:
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            name = stap_escape(name)
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            if is_string(type_):
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                fields.extend([('4b', 'arg%s_len' % name),
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                               ('.*s', 'arg%s_len, arg%s_str' % (name, name))])
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            else:
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                fields.append(('8b', name))
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        # Emit the entire record in a single SystemTap printf()
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        fmt_str = '%'.join(fmt for fmt, _ in fields)
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        arg_str = ', '.join(arg for _, arg in fields)
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        out('    printf("%%8b%%%(fmt_str)s", 1, %(arg_str)s)',
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            fmt_str=fmt_str, arg_str=arg_str)
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        out('}')
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    out()
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