trace: Conditionally trace events based on their per-vCPU state

Events with the 'vcpu' property are conditionally emitted according to
their per-vCPU state. Other events are emitted normally based on their
global tracing state.

Note that the per-vCPU condition check applies to all tracing backends.

Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Lluís Vilanova 2016-07-11 12:53:46 +02:00 committed by Stefan Hajnoczi
parent 4815185902
commit 40b9cd25f7
6 changed files with 57 additions and 29 deletions

View File

@ -6,7 +6,7 @@ DTrace/SystemTAP backend.
"""
__author__ = "Lluís Vilanova <vilanova@ac.upc.edu>"
__copyright__ = "Copyright 2012-2014, Lluís Vilanova <vilanova@ac.upc.edu>"
__copyright__ = "Copyright 2012-2016, Lluís Vilanova <vilanova@ac.upc.edu>"
__license__ = "GPL version 2 or (at your option) any later version"
__maintainer__ = "Stefan Hajnoczi"
@ -41,6 +41,6 @@ def generate_h_begin(events):
def generate_h(event):
out(' QEMU_%(uppername)s(%(argnames)s);',
out(' QEMU_%(uppername)s(%(argnames)s);',
uppername=event.name.upper(),
argnames=", ".join(event.args.names()))

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@ -30,17 +30,17 @@ def generate_h(event):
if len(event.args) > 0:
argnames = ", " + argnames
out(' {',
' char ftrace_buf[MAX_TRACE_STRLEN];',
' int unused __attribute__ ((unused));',
' int trlen;',
' if (trace_event_get_state(%(event_id)s)) {',
' trlen = snprintf(ftrace_buf, MAX_TRACE_STRLEN,',
' "%(name)s " %(fmt)s "\\n" %(argnames)s);',
' trlen = MIN(trlen, MAX_TRACE_STRLEN - 1);',
' unused = write(trace_marker_fd, ftrace_buf, trlen);',
out(' {',
' char ftrace_buf[MAX_TRACE_STRLEN];',
' int unused __attribute__ ((unused));',
' int trlen;',
' if (trace_event_get_state(%(event_id)s)) {',
' trlen = snprintf(ftrace_buf, MAX_TRACE_STRLEN,',
' "%(name)s " %(fmt)s "\\n" %(argnames)s);',
' trlen = MIN(trlen, MAX_TRACE_STRLEN - 1);',
' unused = write(trace_marker_fd, ftrace_buf, trlen);',
' }',
' }',
' }',
name=event.name,
args=event.args,
event_id="TRACE_" + event.name.upper(),

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@ -6,7 +6,7 @@ Stderr built-in backend.
"""
__author__ = "Lluís Vilanova <vilanova@ac.upc.edu>"
__copyright__ = "Copyright 2012-2014, Lluís Vilanova <vilanova@ac.upc.edu>"
__copyright__ = "Copyright 2012-2016, Lluís Vilanova <vilanova@ac.upc.edu>"
__license__ = "GPL version 2 or (at your option) any later version"
__maintainer__ = "Stefan Hajnoczi"
@ -30,15 +30,21 @@ def generate_h(event):
if len(event.args) > 0:
argnames = ", " + argnames
out(' if (trace_event_get_state(%(event_id)s)) {',
' struct timeval _now;',
' gettimeofday(&_now, NULL);',
' qemu_log_mask(LOG_TRACE, "%%d@%%zd.%%06zd:%(name)s " %(fmt)s "\\n",',
' getpid(),',
' (size_t)_now.tv_sec, (size_t)_now.tv_usec',
' %(argnames)s);',
' }',
event_id="TRACE_" + event.name.upper(),
if "vcpu" in event.properties:
# already checked on the generic format code
cond = "true"
else:
cond = "trace_event_get_state(%s)" % ("TRACE_" + event.name.upper())
out(' if (%(cond)s) {',
' struct timeval _now;',
' gettimeofday(&_now, NULL);',
' qemu_log_mask(LOG_TRACE, "%%d@%%zd.%%06zd:%(name)s " %(fmt)s "\\n",',
' getpid(),',
' (size_t)_now.tv_sec, (size_t)_now.tv_usec',
' %(argnames)s);',
' }',
cond=cond,
name=event.name,
fmt=event.fmt.rstrip("\n"),
argnames=argnames)

View File

@ -36,7 +36,7 @@ def generate_h_begin(events):
def generate_h(event):
out(' _simple_%(api)s(%(args)s);',
out(' _simple_%(api)s(%(args)s);',
api=event.api(),
args=", ".join(event.args.names()))
@ -68,16 +68,23 @@ def generate_c(event):
if len(event.args) == 0:
sizestr = '0'
event_id = 'TRACE_' + event.name.upper()
if "vcpu" in event.properties:
# already checked on the generic format code
cond = "true"
else:
cond = "trace_event_get_state(%s)" % event_id
out('',
' if (!trace_event_get_state(%(event_id)s)) {',
' if (!%(cond)s) {',
' return;',
' }',
'',
' if (trace_record_start(&rec, %(event_id)s, %(size_str)s)) {',
' return; /* Trace Buffer Full, Event Dropped ! */',
' }',
event_id='TRACE_' + event.name.upper(),
cond=cond,
event_id=event_id,
size_str=sizestr)
if len(event.args) > 0:

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@ -6,7 +6,7 @@ LTTng User Space Tracing backend.
"""
__author__ = "Lluís Vilanova <vilanova@ac.upc.edu>"
__copyright__ = "Copyright 2012-2014, Lluís Vilanova <vilanova@ac.upc.edu>"
__copyright__ = "Copyright 2012-2016, Lluís Vilanova <vilanova@ac.upc.edu>"
__license__ = "GPL version 2 or (at your option) any later version"
__maintainer__ = "Stefan Hajnoczi"
@ -30,6 +30,6 @@ def generate_h(event):
if len(event.args) > 0:
argnames = ", " + argnames
out(' tracepoint(qemu, %(name)s%(tp_args)s);',
out(' tracepoint(qemu, %(name)s%(tp_args)s);',
name=event.name,
tp_args=argnames)

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@ -23,21 +23,36 @@ def generate(events, backend):
'#define TRACE__GENERATED_TRACERS_H',
'',
'#include "qemu-common.h"',
'#include "trace/control.h"',
'')
backend.generate_begin(events)
for e in events:
if "vcpu" in e.properties:
trace_cpu = next(iter(e.args))[1]
cond = "trace_event_get_vcpu_state(%(cpu)s,"\
" TRACE_%(id)s,"\
" TRACE_VCPU_%(id)s)"\
% dict(
cpu=trace_cpu,
id=e.name.upper())
else:
cond = "true"
out('',
'static inline void %(api)s(%(args)s)',
'{',
' if (%(cond)s) {',
api=e.api(),
args=e.args)
args=e.args,
cond=cond)
if "disable" not in e.properties:
backend.generate(e)
out('}')
out(' }',
'}')
backend.generate_end(events)