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trace: use static event ID mapping in simpletrace.stp

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This is a partial revert of commit
7f1b588f20 ("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>
This commit is contained in:
Stefan Hajnoczi 2017-08-15 09:44:29 +01:00
parent 5681da2922
commit d6b76d6805
1 changed files with 2 additions and 29 deletions
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31
scripts/tracetool/format/simpletrace_stap.py
View file

@ -22,33 +22,8 @@ def global_var_name(name):
return probeprefix().replace(".", "_") + "_" + name
def generate(events, backend, group):
id_map = global_var_name("event_name_to_id_map")
next_id = global_var_name("event_next_id")
map_func = global_var_name("simple_trace_map_event")
out('/* This file is autogenerated by tracetool, do not edit. */',
'',
'global %(id_map)s',
'global %(next_id)s',
'function %(map_func)s(name)',
'',
'{',
' if (!([name] in %(id_map)s)) {',
' %(id_map)s[name] = %(next_id)s',
' name_len = strlen(name)',
' printf("%%8b%%8b%%4b%%.*s", 0, ',
' %(next_id)s, name_len, name_len, name)',
' %(next_id)s = %(next_id)s + 1',
' }',
' return %(id_map)s[name]',
'}',
'probe begin',
'{',
' printf("%%8b%%8b%%8b", 0xffffffffffffffff, 0xf2b177cb0aa429b4, 4)',
'}',
'',
id_map=id_map,
next_id=next_id,
map_func=map_func)
'')
for event_id, e in enumerate(events):
if 'disable' in e.properties:
@ -56,9 +31,7 @@ def generate(events, backend, group):
out('probe %(probeprefix)s.simpletrace.%(name)s = %(probeprefix)s.%(name)s ?',
'{',
' id = %(map_func)s("%(name)s")',
probeprefix=probeprefix(),
map_func=map_func,
name=e.name)
# Calculate record size
@ -77,7 +50,7 @@ def generate(events, backend, group):
sizestr = ' + '.join(sizes)
# Generate format string and value pairs for record header and arguments
fields = [('8b', 'id'),
fields = [('8b', str(event_id)),
('8b', 'gettimeofday_ns()'),
('4b', sizestr),
('4b', 'pid()')]