Some trace backends will compile code based on the declared trace
events. It should not be assumed that the backends can resolve any QEMU
specific typedefs. So trace events should restrict their argument
types to the standard C types and fixed size integer types. Any complex
pointer types can be declared as "void *" for purposes of trace events,
since nothing will be dereferencing these pointer arguments.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-id: 20180308155524.5082-3-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Improves error messages from:
ValueError: Error on line 72: need more than 1 value to unpack
To
ValueError: Error at /home/berrange/src/virt/qemu/trace-events:72:
need more than 1 value to unpack
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20180306154650.24075-1-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Using the greedy star matching, arguments like "...%"PRIx64 caused issues
for functions with multiple PRI formats.
The issue was only seen with the ust backend, as it is the only one
using the format regex.
The result for many functions was that the arguments coming after the
greedy star end was left out of the tracepoint, and in some cases some
of the arguments that was traced had the wrong format.
Signed-off-by: Jon Emil Jahren <jonemilj@gmail.com>
Message-id: 20180129041648.30884-2-jonemilj@gmail.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
C functions with no arguments must be declared foo(void) instead of
foo(). The tracetool argument list parser has never accepted an empty
argument list. This patch adds a clear error message for this error
case.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20180110202553.31889-4-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The terminology used by tracetool is not consistent with C sprintf or
docs/devel/tracing.txt. The word "formats" is sometimes used to mean
"format strings".
This patch clarifies comments and error messages that contain this word.
Note that the error message lines are longer than 80 characters but I
have not wrapped them to aid grepping.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20180110202553.31889-3-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Include the file line number in the message that is printed when
trace-events parse errors are raised.
[Use enumerate(fobj, 1) to avoid having to increment a 0-based index
later, as suggested by Eric Blake.
--Stefan]
Suggested-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20180110202553.31889-2-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
QEMU keeps track of trace event enabled/disabled state and provides
monitor commands to inspect and modify the "dstate". SystemTap and
LTTng UST maintain independent enabled/disabled states for each trace
event, the other backends rely on QEMU dstate.
Introduce a new per-event macro that combines backend-specific dstate
like this:
#define TRACE_MY_EVENT_BACKEND_DSTATE() ( \
QEMU_MY_EVENT_ENABLED() || /* SystemTap */ \
tracepoint_enabled(qemu, my_event) /* LTTng UST */ || \
false)
This will be used to extend trace_event_get_state() in the next patch.
[Daniel Berrange pointed out that QEMU_MY_EVENT_ENABLED() must be true
by default, not false. This way events will fire even if the DTrace
implementation does not implement the SystemTap semaphores feature.
Ubuntu Precise uses lttng-ust-dev 2.0.2 which does not have
tracepoint_enabled(), so we need a compatibility wrapper to keep Travis
builds passing.
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170731140718.22010-2-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
fixup! trace: add TRACE_<event>_BACKEND_DSTATE()
If an event is dynamically disabled, the TCG code that calls the
execution-time tracer is not generated.
Removes the overheads of execution-time tracers for dynamically disabled
events. As a bonus, also avoids checking the event state when the
execution-time tracer is called from TCG-generated code (since otherwise
TCG would simply not call it).
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-id: 149915799921.6295.13067154430923434035.stgit@frigg.lan
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The UST trace backend can only cope with upto 10 arguments. To ensure we
don't exceed the limit when UST is not compiled in, disallow more than
10 arguments upfront.
This prevents the case where:
commit 0fc8aec7de
Author: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
Date: Tue Apr 18 10:20:20 2017 +0800
COLO-compare: Optimize tcp compare trace event
Optimize two trace events as one, adjust print format make
it easy to read. rename trace_colo_compare_pkt_info_src/dst
to trace_colo_compare_tcp_info.
regressed the fix done in
commit 2dfe5113b1
Author: Alex Bennée <alex.bennee@linaro.org>
Date: Fri Oct 28 14:25:59 2016 +0100
net: split colo_compare_pkt_info into two trace events
It seems there is a limit to the number of arguments a UST trace event
can take and at 11 the previous trace command broke the build. Split the
trace into a src pkt and dst pkt trace to fix this.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 20161028132559.8324-1-alex.bennee@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Now we get an immediate fail even when UST is disabled:
GEN net/trace.h
Traceback (most recent call last):
File "/home/berrange/src/virt/qemu/scripts/tracetool.py", line 154, in <module>
main(sys.argv)
File "/home/berrange/src/virt/qemu/scripts/tracetool.py", line 145, in main
events.extend(tracetool.read_events(fh))
File "/home/berrange/src/virt/qemu/scripts/tracetool/__init__.py", line 307, in read_events
event = Event.build(line)
File "/home/berrange/src/virt/qemu/scripts/tracetool/__init__.py", line 244, in build
event = Event(name, props, fmt, args)
File "/home/berrange/src/virt/qemu/scripts/tracetool/__init__.py", line 196, in __init__
"argument count" % name)
ValueError: Event 'colo_compare_tcp_info' has more than maximum permitted argument count
Makefile:96: recipe for target 'net/trace.h-timestamp' failed
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20170426153900.21066-1-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The declarations in the generated-tracers.h file are
assuming there's only ever going to be one instance
of this header, as they are not namespaced. When we
have one header per event group, if a single source
file needs to include multiple sets of trace events,
the symbols will all clash.
This change thus introduces a '--group NAME' arg to the
'tracetool' program. This will cause all the symbols in
the generated header files to be given a unique namespace.
If no group is given, the group name 'common' is used,
which is suitable for the current usage where there is
only one global trace-events file used for code generation.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
Message-id: 1475588159-30598-21-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Move the reading of events out of the 'tracetool.generate'
method and into tracetool.main, so that the latter is not
tied to generating from a single source of events.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-19-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The _read_events method is used by callers outside of
its module, so should be a public method, not private.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-18-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Currently we only expose a TraceEvent array, which must
be indexed via the TraceEventID enum constants. This
changes the generator to expose a named TraceEvent
instance for each event, with an _EVENT suffix.
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-10-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Instead of having a global dstate array, declare a single
'uint16 TRACE_${EVENT_NAME}_DSTATE' variable for each
trace event. Record a pointer to this variable in the
TraceEvent struct too.
By turning trace_event_get_state_dynamic_by_id into a
macro, this still hits the fast path, and cache affinity
is ensured by declaring all the uint16 vars adjacent to
each other.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-7-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Formalizes the existence of the 'event_trans' and 'event_exec' event
attributes, which until now were monkey-patched only when necessary.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Message-id: 145640558759.20978.6374959404425591089.stgit@localhost
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This property identifies events that trace vCPU-specific information.
It adds a "CPUState*" argument to events with the property, identifying
the vCPU raising the event. TCG translation events also have a
"TCGv_env" implicit argument that is later used as the "CPUState*"
argument at execution time.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Message-id: 145641861797.30295.6991314023181842105.stgit@localhost
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The current code forces the use of a chain of ".original" dereferences,
which looks odd.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Message-id: 145641858988.30295.7223459456488075843.stgit@localhost
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Lets the user manage event arguments as a list, and simplifies argument
concatenation.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 145641858432.30295.3069911069472672646.stgit@localhost
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
simpletrace.py does not recognize the tcg option while reading trace-events file. In result simpletrace does not work on binary traces and tcg enabled events. Moved transformation of tcg enabled events to _read_events() which is used by simpletrace.
Signed-off-by: Christoph Seifert <christoph.seifert@posteo.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This only affects lttng user space tracing at the moment.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Use \w for properties and trace event names since they are both drawn
from [a-zA-Z0-9_] character sets.
The .* for matching properties was too aggressive and caused the
following failure with foo(int rc) "(this is a test)":
Traceback (most recent call last):
File "scripts/tracetool.py", line 139, in <module>
main(sys.argv)
File "scripts/tracetool.py", line 134, in main
binary=binary, probe_prefix=probe_prefix)
File "scripts/tracetool/__init__.py", line 334, in generate
events = _read_events(fevents)
File "scripts/tracetool/__init__.py", line 262, in _read_events
res.append(Event.build(line))
File "scripts/tracetool/__init__.py", line 225, in build
return Event(name, props, fmt, args, arg_fmts)
File "scripts/tracetool/__init__.py", line 185, in __init__
% ", ".join(unknown_props))
ValueError: Unknown properties: foo(int, rc)
Cc: Lluís Vilanova <vilanova@ac.upc.edu>
Reported-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1411468626-20450-1-git-send-email-stefanha@redhat.com
TCG-enabled events start with two format strings. Delay per-argument format
computation until requested ('Event.formats').
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Generates file "trace/generated-helpers.h" with TCG helper declarations to trace
events in guest code at execution time ('trace_${event}_exec_proxy').
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Adds support to compile QEMU with multiple tracing backends at the same time.
For example, you can compile QEMU with:
$ ./configure --enable-trace-backends=ftrace,dtrace
Where 'ftrace' can be handy for having an in-flight record of events, and 'dtrace' can be later used to extract more information from the system.
This patch allows having both available without recompiling QEMU.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Backends now only contain the essential backend-specific code, and most of the work is moved to frontend code.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Makes it easier to ensure proper naming across the different frontends and backends.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The str.rpartition() function is related to str.split() and is used for
splitting strings. It was introduced in Python 2.5 and therefore cannot
be used in tracetool as Python 2.4 compatibility is required.
Replace the code using str.rsplit().
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
In Python 2.5 keyword arguments were added to __import__(). Avoid using
them to achieve Python 2.4 compatibility.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
The tracetool script is written in shell and has hit several portability
problems due to shell quirks or external tools across host platforms.
Additionally the amount of string processing and lack of real data
structures makes it tough to implement code generator backends for
tracers that are more complex.
This patch replaces the shell version of tracetool with a Python
version. The new tracetool design is:
scripts/tracetool.py - top-level script
scripts/tracetool/backend/ - tracer backends live here (simple, ust)
scripts/tracetool/format/ - output formats live here (.c, .h)
There is common code for trace-events definition parsing so that
backends can focus on generating code rather than parsing input.
Support for all existing backends (nop, stderr, simple, ust,
and dtrace) is added back in follow-up patches.
[Commit description written by Stefan Hajnoczi]
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
