This interface decouples event obtaining from interaction.
Events can be obtained through three different methods:
* identifier
* name
* simple wildcard pattern
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Missed when commit 4c3b5a48 moved it.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Harsh Prateek Bora <harsh@linux.vnet.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
commit 88affa1c monitor: remove unused do_info_trace
has removed "info trace" function from monitor, so remove it from documents.
Signed-off-by: Liming Wang <walimisdev@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This patch corrects the configure's trace option in docs/tracing.txt.
Signed-off-by: Jun Koi <junkoi2004@gmail.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>
A basic wildcard matching is supported in both the monitor command
"trace-event" and the events list file. That means you can enable/disable
the events having a common prefix in a batch. For example, virtio-blk trace
events could be enabled using:
trace-event virtio_blk_* on
Signed-off-by: Mark Wu <wudxw@linux.vnet.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
The events 'qemu_malloc' and 'qemu_free' used in the examples no longer exist,
so use 'qemu_vmalloc' and 'qemu_vfree' instead.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
String arguments are useful for producing human-readable traces without
post-processing (e.g. stderr backend). Although the simple backend
cannot handles strings all others can. Strings should be allowed and
the simple backend can be extended to support them.
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>
The "-trace events" argument can be used to provide a file with a list of trace
event names that will be enabled prior to starting execution, thus providing
early tracing.
This saves the user from manually toggling event states through the monitor
interface or whichever backend-specific interface.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
The current interface is generic for this small set of operations, and thus
other backends can easily modify the "trace/control.c" file to add their own
implementation.
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>
Trace events outside the global mutex cannot be used with the simple
trace backend since it is not thread-safe. There is no check to prevent
them being enabled so people sometimes learn this the hard way.
This patch restructures the simple trace backend with a ring buffer
suitable for multiple concurrent writers. A writeout thread empties the
trace buffer when threshold fill levels are reached. Should the
writeout thread be unable to keep up with trace generation, records will
simply be dropped.
Each time events are dropped a special record is written to the trace
file indicating how many events were dropped. The event ID is
0xfffffffffffffffe and its signature is dropped(uint32_t count).
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
The following additions to the tracing documentation are included:
1. Move "stderr" backend documentation to top-level and out of "simple"
backend. Include hints on when this backend is useful.
2. Document the "simple" backend thread-safety limitation.
3. Document the "dtrace" backend for SystemTap.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
This backend sends trace events to standard error output during the emulation.
Also add a "--list-backends" option to tracetool, so configure script can
display the list of available backends.
Signed-off-by: Fabien Chouteau <chouteau@adacore.com>
Acked-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Document the restriction that format strings must begin and end with
double quotes. This is for easy parsing since we don't run cpp over
trace-events.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
It is not portable to use "%ld" for int64_t because int64_t may have
type long on 64-bit platforms and long long on 32-bit platforms. Use
the standard library PRId64 macros to keep format strings portable.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
