736ec1677f
The trace-events "disable" keyword turns an event into a nop at compile-time. This is important for high-frequency events that can impact performance. The "disable" keyword is currently broken in the simple trace backend. This patch fixes the problem as follows: Trace events are identified by their TraceEventID number. When events are disabled there are two options for assigning TraceEventID numbers: 1. Skip disabled events and don't assign them a number. 2. Assign numbers for all events regardless of the disabled keyword. The simple trace backend and its binary file format uses approach #1. The tracetool infrastructure has been using approach #2 for a while. The result is that the numbers used in simple trace files do not correspond with TraceEventIDs. In trace/simple.c we assumed that they are identical and therefore emitted bogus numbers. This patch fixes the bug by using TraceEventID for trace_event_id() while sticking to approach #1 for simple trace file numbers. This preserves simple trace file format compatibility. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
102 lines
2.9 KiB
Python
102 lines
2.9 KiB
Python
#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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"""
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Simple built-in backend.
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"""
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__author__ = "Lluís Vilanova <vilanova@ac.upc.edu>"
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__copyright__ = "Copyright 2012, Lluís Vilanova <vilanova@ac.upc.edu>"
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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@linux.vnet.ibm.com"
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from tracetool import out
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PUBLIC = True
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def is_string(arg):
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strtype = ('const char*', 'char*', 'const char *', 'char *')
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if arg.lstrip().startswith(strtype):
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return True
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else:
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return False
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def c(events):
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out('#include "trace.h"',
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'#include "trace/control.h"',
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'#include "trace/simple.h"',
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'',
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)
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for num, event in enumerate(events):
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out('void trace_%(name)s(%(args)s)',
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'{',
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' TraceBufferRecord rec;',
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name = event.name,
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args = event.args,
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)
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sizes = []
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for type_, name in event.args:
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if is_string(type_):
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out(' size_t arg%(name)s_len = %(name)s ? MIN(strlen(%(name)s), MAX_TRACE_STRLEN) : 0;',
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name = name,
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)
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strsizeinfo = "4 + arg%s_len" % name
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sizes.append(strsizeinfo)
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else:
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sizes.append("8")
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sizestr = " + ".join(sizes)
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if len(event.args) == 0:
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sizestr = '0'
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out('',
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' TraceEvent *eventp = trace_event_id(%(event_enum)s);',
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' bool _state = trace_event_get_state_dynamic(eventp);',
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' if (!_state) {',
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' return;',
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' }',
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'',
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' if (trace_record_start(&rec, %(event_id)s, %(size_str)s)) {',
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' return; /* Trace Buffer Full, Event Dropped ! */',
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' }',
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event_enum = 'TRACE_' + event.name.upper(),
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event_id = num,
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size_str = sizestr,
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)
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if len(event.args) > 0:
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for type_, name in event.args:
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# string
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if is_string(type_):
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out(' trace_record_write_str(&rec, %(name)s, arg%(name)s_len);',
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name = name,
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)
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# pointer var (not string)
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elif type_.endswith('*'):
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out(' trace_record_write_u64(&rec, (uintptr_t)(uint64_t *)%(name)s);',
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name = name,
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)
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# primitive data type
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else:
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out(' trace_record_write_u64(&rec, (uint64_t)%(name)s);',
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name = name,
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)
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out(' trace_record_finish(&rec);',
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'}',
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'')
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def h(events):
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for event in events:
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out('void trace_%(name)s(%(args)s);',
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name = event.name,
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args = event.args,
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)
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