This new tracetool "format" generates a SystemTap .stp file that outputs
simpletrace binary trace data.
In contrast to simpletrace or ftrace, SystemTap does not define its own
trace format. All output from SystemTap is generated by .stp files.
This patch lets us generate a .stp file that outputs in the simpletrace
binary format.
This makes it possible to reuse simpletrace.py to analyze traces
recorded using SystemTap. The simpletrace binary format is especially
useful for long-running traces like flight-recorder mode where string
formatting can be expensive.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
SystemTap reserved words sometimes conflict with QEMU variable names.
We escape them to prevent conflicts.
Move escaping into its own function so the next patch can reuse it.
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>
* A new format is required to generate definitions for ust tracepoints.
Files ust_events_h.py and ust_events_c.py define common macros, while
new function ust_events_h in events.py does the actual definition of
each tracepoint.
* ust.py generates the new interface for calling userspace tracepoints
with LTTng 2.x, replacing trace_name(args) to tracepoint(name, args).
* As explained in ust_events_c.py, -Wredundant-decls gives a warning
when compiling with gcc 4.7 or older. This is specific to lttng-ust so
for now use a pragma clause to avoid getting a warning.
Signed-off-by: Mohamad Gebai <mohamad.gebai@polymtl.ca>
Reviewed-by: Alex Bennée <alex@bennee.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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>
The header is not necessary, given that the simple backend does not define any
inlined tracing routines.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This patch adds a ftrace tracing backend which sends trace event to
ftrace marker file. You can effectively compare qemu trace data and
kernel(especially, kvm.ko when using KVM) trace data.
The ftrace backend is restricted to Linux only.
To try out the ftrace backend:
$ ./configure --trace-backend=ftrace
$ make
if you use KVM, enable kvm events in ftrace:
# sudo echo 1 > /sys/kernel/debug/tracing/events/kvm/enable
After running qemu by root user, you can get the trace:
# cat /sys/kernel/debug/tracing/trace
Signed-off-by: Eiichi Tsukata <eiichi.tsukata.xh@hitachi.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The backend is forced to dump event numbers using 64 bits, as TraceEventID is
an enum.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Uses tracetool to generate a backend-independent tracing event description
(struct TraceEvent).
The values for such structure are generated with the non-public "events"
backend ("events-c" frontend).
The generation of the defines to check if an event is statically enabled is also
moved to the "events" backend ("events-h" frontend).
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Public backends are those printed by "--list-backends" and thus considered valid
by the configure script.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
--
Changes in v2:
* Do not depend on "qemu-timer-common.o".
* Use "$(obj)" in rules to refer to the build sub-directory.
* Remove dependencies against "$(GENERATED_HEADERS)".
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Over time various systemtap reserved words have been blacklisted
in the trace backend generator. The list is not complete though,
so there is continued risk of problems in the future. Preempt
such problems by specifying the full list of systemtap keywords
listed in its parser as identified here:
http://sourceware.org/ml/systemtap/2012-q4/msg00157.html
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
gcc complains when a 32 bit pointer is casted to a 64 bit integer.
Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Existing simpletrace backend allows to trace at max 6 args and does not
support strings. This newer tracelog format gets rid of fixed size records
and therefore allows to trace variable number of args including strings.
Sample trace with strings:
v9fs_version 0.000 tag=0xffff id=0x64 msize=0x2000 version=9P2000.L
v9fs_version_return 6.705 tag=0xffff id=0x64 msize=0x2000 version=9P2000.L
Signed-off-by: Harsh Prateek Bora <harsh@linux.vnet.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
The pkgutil.iter_modules() function provides a way to enumerate child
modules. Unfortunately it's missing in Python <2.7 so we must implement
similar behavior ourselves.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
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>
Language keywords cannot be used as argument names. The DTrace backend
appends an underscore to the argument name in order to make the argument
name legal.
This patch adds 'in', 'next', and 'self' keywords to dtrace.py.
Also drop the unnecessary argument name lstrip() call. The
Arguments.build() method already ensures there is no space around
argument names. Furthermore it is misleading to do the lstrip() *after*
checking against keywords because the keyword check would not match if
spaces were in the name.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Reviewed-by: Alon Levy <alevy@redhat.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>
It has happened more than once that patches that look perfectly sane
and work with simpletrace broke systemtap because they use 'next' as an
argument name for a tracing function. However, 'next' is a keyword for
systemtap, so we shouldn't use it.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* stefanha/tracing:
tracetool: dtrace: handle in and next reserved words
tracetool: dtrace disabled-events fix
Makefile.target: code stp dependency on trace-events
Some locale settings let make fail or create wrong results
because tr '[:lower:]' '[:upper:]' which is used to convert
from lower to upper case depends on the locale.
With locale tr_TR.UTF-8, lower case 'i' is not converted to 'I'.
This results in wrong entries in config-host.h like these ones:
#define CONFIG_QEMU_PREFiX "/usr/local"
#define CONFIG_QEMU_BiNDiR "/usr/local/bin"
This problem was reported by Emre Ersin.
The same problem occurs when configure creates the target specific
files config-target.mak. They get wrong declarations:
TARGET_CRiS=y
TARGET_i386=y
TARGET_MiCROBLAZE=y
TARGET_MiPS64=y
TARGET_MiPS=y
TARGET_UNiCORE32=y
It is sufficient to restrict the conversion to the characters a-z.
Using this explicit range avoids the dependency on the locale
settings and is also shorter.
v2:
POSIX says that 'tr a-z' is unspecified outside of the POSIX
locale, so we must set LC_ALL=C to make sure that we are using
POSIX (hint from Eric Blake, thanks).
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
If there are "disabled" entries in the trace-events file then
linetod_nop() is called if the backend is dtrace, it's currently
not present. Also equivalent fix for stap.
Signed-off-by: Lee Essen <lee.essen@nowonline.co.uk>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
SystemTap provides a "semaphore" that can optionally be tested before
executing a trace event. The purpose of this mechanism is to skip
expensive tracing code when the trace event is disabled.
For example, some applications may have trace events that format or
convert strings for trace events. This expensive processing should only
be done in the case where the trace event is enabled.
Since QEMU's generated trace events never have such special-purpose
code, there is no reason to add the semaphore check.
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Adds a 'TRACE_${NAME}_ENABLED' preprocessor define for each tracing event in
"trace.h".
This lets the user conditionally compile code with a relatively high execution
cost that is only necessary when producing the tracing information for an event
that is enabled.
Note that events using this define will probably have the "disable" property by
default, in order to avoid such costs on regular builds.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
The tracetool parser only picks up PRI*64 and other format string macros
when enclosed between double quoted strings. Lift this restriction by
extracting everything after the closing ')' as the format string:
cpu_set_apic_base(uint64_t val) "%016"PRIx64
^^ ^^
One trick here: it turns out that backslashes in the format string like
"\n" were being interpreted by echo(1). Fix this by using the POSIX
printf(1) command instead. Although it normally does not make sense to
include backslashes in trace event format strings, an injected newline
causes tracetool to emit a broken header file and I want to eliminate
cases where broken output is emitted, even if the input was bad.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Uses the generic interface provided in "trace/control.h" in order to provide
a programmatic interface as well as command line and monitor controls.
Signed-off-by: Fabien Chouteau <chouteau@adacore.com>
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Note that this refers to the backend-specific state (whether the output must be
generated), not the event "disabled" property (which always uses the "nop"
backend).
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Any event with the keyword/property "disable" generates an empty trace event
using the "nop" backend, regardless of the current backend.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
This adds/modifies the following functions:
* get_name: Get _only_ the event name
* has_property: Return whether an event has a property (keyword before the event
name)
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
