| Message ID | 1395680694-27758-1-git-send-email-alex.bennee@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
On Mon, Mar 24, 2014 at 05:04:54PM +0000, alex.bennee@linaro.org wrote: > From: Alex Bennée <alex.bennee@linaro.org> > > This makes the UST backend pay attention to the format string arguments > that are defined when defining payload data. With this you can now > ensure integers are reported in hex mode if you want. > > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > --- > scripts/tracetool/__init__.py | 13 +++++++++++-- > scripts/tracetool/backend/ust.py | 16 ++++++++++++---- > 2 files changed, 23 insertions(+), 6 deletions(-) How are strings handled, can LTTng copy them from the QEMU process' memory space? Stefan
Stefan Hajnoczi <stefanha@redhat.com> writes: > On Mon, Mar 24, 2014 at 05:04:54PM +0000, alex.bennee@linaro.org wrote: >> From: Alex Bennée <alex.bennee@linaro.org> >> >> This makes the UST backend pay attention to the format string arguments >> that are defined when defining payload data. With this you can now >> ensure integers are reported in hex mode if you want. >> >> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> >> --- >> scripts/tracetool/__init__.py | 13 +++++++++++-- >> scripts/tracetool/backend/ust.py | 16 ++++++++++++---- >> 2 files changed, 23 insertions(+), 6 deletions(-) > > How are strings handled, can LTTng copy them from the QEMU process' > memory space? lttng provides ctf_string for passing strings to the payload. But I wouldn't expect to use them for the result of format string calculations as that would defeat the point of the low impact tracing. There are a number of trace-events that pass strings for various things. I've not actually experimented with the output of any of them though. > > Stefan
On Tue, Mar 25, 2014 at 02:49:42PM +0000, Alex Bennée wrote: > > Stefan Hajnoczi <stefanha@redhat.com> writes: > > > On Mon, Mar 24, 2014 at 05:04:54PM +0000, alex.bennee@linaro.org wrote: > >> From: Alex Bennée <alex.bennee@linaro.org> > >> > >> This makes the UST backend pay attention to the format string arguments > >> that are defined when defining payload data. With this you can now > >> ensure integers are reported in hex mode if you want. > >> > >> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > >> --- > >> scripts/tracetool/__init__.py | 13 +++++++++++-- > >> scripts/tracetool/backend/ust.py | 16 ++++++++++++---- > >> 2 files changed, 23 insertions(+), 6 deletions(-) > > > > How are strings handled, can LTTng copy them from the QEMU process' > > memory space? > > lttng provides ctf_string for passing strings to the payload. But I > wouldn't expect to use them for the result of format string calculations > as that would defeat the point of the low impact tracing. > > There are a number of trace-events that pass strings for various things. > I've not actually experimented with the output of any of them though. Sounds like it should work but can you test it? Try enabling the bdrv_open_common() trace event when booting a guest. You should see the filename of the disk image file. Stefan
I can confirm that it works for me, I can see the disk image file name in the payload of brdv_open_common events. Mohamad On 03/26/2014 04:27 AM, Stefan Hajnoczi wrote: > On Tue, Mar 25, 2014 at 02:49:42PM +0000, Alex Bennée wrote: >> Stefan Hajnoczi <stefanha@redhat.com> writes: >> >>> On Mon, Mar 24, 2014 at 05:04:54PM +0000, alex.bennee@linaro.org wrote: >>>> From: Alex Bennée <alex.bennee@linaro.org> >>>> >>>> This makes the UST backend pay attention to the format string arguments >>>> that are defined when defining payload data. With this you can now >>>> ensure integers are reported in hex mode if you want. >>>> >>>> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> >>>> --- >>>> scripts/tracetool/__init__.py | 13 +++++++++++-- >>>> scripts/tracetool/backend/ust.py | 16 ++++++++++++---- >>>> 2 files changed, 23 insertions(+), 6 deletions(-) >>> How are strings handled, can LTTng copy them from the QEMU process' >>> memory space? >> lttng provides ctf_string for passing strings to the payload. But I >> wouldn't expect to use them for the result of format string calculations >> as that would defeat the point of the low impact tracing. >> >> There are a number of trace-events that pass strings for various things. >> I've not actually experimented with the output of any of them though. > Sounds like it should work but can you test it? Try enabling the > bdrv_open_common() trace event when booting a guest. You should see the > filename of the disk image file. > > Stefan
diff --git a/scripts/tracetool/__init__.py b/scripts/tracetool/__init__.py index 175df08..abcdc49 100644 --- a/scripts/tracetool/__init__.py +++ b/scripts/tracetool/__init__.py @@ -118,13 +118,16 @@ class Event(object): Properties of the event. args : Arguments The event arguments. + arg_fmts : str + The format strings for each arugment. """ _CRE = re.compile("((?P<props>.*)\s+)?(?P<name>[^(\s]+)\((?P<args>[^)]*)\)\s*(?P<fmt>\".*)?") + _FMT = re.compile("(%\w+|%.*PRI\S+)") _VALID_PROPS = set(["disable"]) - def __init__(self, name, props, fmt, args): + def __init__(self, name, props, fmt, args, arg_fmts): """ Parameters ---------- @@ -136,11 +139,15 @@ class Event(object): Event printing format. args : Arguments Event arguments. + arg_fmts : list of str + Format strings for each argument + """ self.name = name self.properties = props self.fmt = fmt self.args = args + self.arg_fmts = arg_fmts unknown_props = set(self.properties) - self._VALID_PROPS if len(unknown_props) > 0: @@ -163,8 +170,10 @@ class Event(object): props = groups["props"].split() fmt = groups["fmt"] args = Arguments.build(groups["args"]) + print "%s: %s and %s" % (name, args, fmt) + arg_fmts = Event._FMT.findall(fmt) - return Event(name, props, fmt, args) + return Event(name, props, fmt, args, arg_fmts) def __repr__(self): """Evaluable string representation for this object.""" diff --git a/scripts/tracetool/backend/ust.py b/scripts/tracetool/backend/ust.py index 41c1c75..cb09958 100644 --- a/scripts/tracetool/backend/ust.py +++ b/scripts/tracetool/backend/ust.py @@ -56,13 +56,21 @@ def ust_events_h(events): args = ", ".join(", ".join(i) for i in e.args), ) - for t,n in e.args: - if ('int' in t) or ('long' in t) or ('unsigned' in t) or ('size_t' in t): + types = e.args.types() + names = e.args.names() + fmts = e.arg_fmts + print "/* %s/%s/%s */" % (types, names, fmts) + for t,n,f in zip(types, names, fmts): + if ('char *' in t) or ('char*' in t): + out(' ctf_string(' + n + ', ' + n + ')') + elif ("%p" in f) or ("x" in f) or ("PRIx" in f): + out(' ctf_integer_hex('+ t + ', ' + n + ', ' + n + ')') + elif ("ptr" in t) or ("*" in t): + out(' ctf_integer_hex('+ t + ', ' + n + ', ' + n + ')') + elif ('int' in t) or ('long' in t) or ('unsigned' in t) or ('size_t' in t): out(' ctf_integer(' + t + ', ' + n + ', ' + n + ')') elif ('double' in t) or ('float' in t): out(' ctf_float(' + t + ', ' + n + ', ' + n + ')') - elif ('char *' in t) or ('char*' in t): - out(' ctf_string(' + n + ', ' + n + ')') elif ('void *' in t) or ('void*' in t): out(' ctf_integer_hex(unsigned long, ' + n + ', ' + n + ')')