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[Qemu-devel] [PATCH for-2.10 v2 1/2] trace: use static event ID mapping
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PATCH for-2.10 v2 1/2] trace: use static event ID mapping in simpletrace.stp |
Date: |
Tue, 15 Aug 2017 09:44:29 +0100 |
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 <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
scripts/tracetool/format/simpletrace_stap.py | 31 ++--------------------------
1 file changed, 2 insertions(+), 29 deletions(-)
diff --git a/scripts/tracetool/format/simpletrace_stap.py
b/scripts/tracetool/format/simpletrace_stap.py
index 144b704bcd..e7e44842ca 100644
--- a/scripts/tracetool/format/simpletrace_stap.py
+++ b/scripts/tracetool/format/simpletrace_stap.py
@@ -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()')]
--
2.13.4