The '-trace' and '--trace' spellings are only both supported in qemu
binary, while for qemu-nbd or qemu-img only '--trace' spelling is
supported. So for the consistency of trace option invocation, we
should use double-dash spelling in our documentation.

This's also mentioned in
https://wiki.qemu.org/BiteSizedTasks#Consistent_option_usage_in_documentation
.
Signed-off-by: NYaowei Bai <baiyaowei@cmss.chinamobile.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-id: 1530674247-31200-1-git-send-email-baiyaowei@cmss.chinamobile.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

When pulling in headers that are in the same directory as the C file (as
opposed to one in include/), we should use its relative path, without a
directory.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>

Code that checks dstate is unaware of SystemTap and LTTng UST dstate, so
the following trace event will not fire when solely enabled by SystemTap
or LTTng UST:

  if (trace_event_get_state(TRACE_MY_EVENT)) {
      str = g_strdup_printf("Expensive string to generate ...",
                            ...);
      trace_my_event(str);
      g_free(str);
  }

Add trace_event_get_state_backends() to fetch backend dstate.  Those
backends that use QEMU dstate fetch it as part of
generate_h_backend_dstate().

Update existing trace_event_get_state() callers to use
trace_event_get_state_backends() instead.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170731140718.22010-3-stefanha@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Every vCPU now uses a separate set of TBs for each set of dynamic
tracing event state values. Each set of TBs can be used by any number of
vCPUs to maximize TB reuse when vCPUs have the same tracing state.

This feature is later used by tracetool to optimize tracing of guest
code events.

The maximum number of TB sets is defined as 2^E, where E is the number
of events that have the 'vcpu' property (their state is stored in
CPUState->trace_dstate).

For this to work, a change on the dynamic tracing state of a vCPU will
force it to flush its virtual TB cache (which is only indexed by
address), and fall back to the physical TB cache (which now contains the
vCPU's dynamic tracing state as part of the hashing function).
Signed-off-by: NLluís Vilanova <vilanova@ac.upc.edu>
Reviewed-by: NRichard Henderson <rth@twiddle.net>
Reviewed-by: NEmilio G. Cota <cota@braap.org>
Signed-off-by: NEmilio G. Cota <cota@braap.org>
Message-id: 149915775266.6295.10060144081246467690.stgit@frigg.lan
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

We need to disable per-vCPU events on a vCPU that is hot-unplugged to
keep the dynamic event state global counters consistent.
Signed-off-by: NLluís Vilanova <vilanova@ac.upc.edu>
Message-id: 148278748055.1404.1570530281528619895.stgit@fimbulvetr.bsc.es
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Currently the generated-events.[ch] files contain the
event dstates, constants and TraceEvent structs, while the
generated-tracers.[ch] files contain the actual trace
probe logic. With the removal of usage of the event enums
from the API there is no longer any compelling reason for
the separation between these files. The generated-events.h
content is only ever needed from the generated-tracers.[ch]
files.

The enums/constants/structs from generated-events.[ch] are
thus moved into the generated-tracers.[ch], so that there
is one less file to be generated.
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NLluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-17-git-send-email-berrange@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

The CPUState struct has a bitmap tracking which VCPU
events are currently active. This is indexed based on
the event ID values, and sized according the maximum
TraceEventVCPUID enum value.

When we start dynamically assigning IDs at runtime,
we can't statically declare a bitmap without making
an assumption about the max event count. This problem
can be solved by dynamically allocating the per-CPU
dstate bitmap.
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NLluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-15-git-send-email-berrange@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Remove the notion of there being a single global array
of trace events, by introducing a method for registering
groups of events.

The module_call_init() needs to be invoked at the start
of any program that wants to make use of the trace
support. Currently this covers system emulators qemu-nbd,
qemu-img and qemu-io.

[Squashed the following fix from Daniel P. Berrange
<berrange@redhat.com>:

linux-user/bsd-user: initialize trace events subsystem

The bsd-user/linux-user programs make use of the CPU emulation
code and this now requires that the trace events subsystem
is enabled, otherwise it'll crash trying to allocate an empty
trace events bitmap for the CPU object.

--Stefan]
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NLluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-14-git-send-email-berrange@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

The TraceEventID and TraceEventVCPUID enums constants are
no longer actually used for anything critical.

The TRACE_EVENT_COUNT limit is used to determine the size
of the TraceEvents array, and can be removed if we just
NULL terminate the array instead.

The TRACE_VCPU_EVENT_COUNT limit is used as a magic value
for marking non-vCPU events, and also for declaring the
size of the trace dstate mask in the CPUState struct.
The former usage can be replaced by a dedicated constant
TRACE_EVENT_VCPU_NONE, defined as (uint32_t)-1. For the
latter usage, we can simply define a constant for the
number of VCPUs, avoiding the need for the full enum.

The only other usages of the enum values can be replaced
by accesing the id/vcpu_id fields via the named TraceEvent
structs.
Reviewed-by: NLluís Vilanova <vilanova@ac.upc.edu>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-11-git-send-email-berrange@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

The trace_event_count, trace_event_id and
trace_event_pattern methods are no longer required
now that everything is using the iterator APIs

The trace_event_set_state and trace_event_set_vcpu_state
macros were also unused.
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NLluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-6-git-send-email-berrange@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Currently methods which want to iterate over trace events,
do so using the trace_event_count() and trace_event_id()
methods. This leaks the concept of a single ID enum to
the callers. There is an alternative trace_event_pattern()
method which can be used in an iteration context, but its
design is stateless, so is not easy to expand it in the
future.

This defines a formal iterator API will provide a future-
proof way of iterating over events.

The iterator is also able to apply a pattern match filter
to events, further removing the need for the pattern
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NLluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-4-git-send-email-berrange@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Every time a vCPU is hot-plugged, it will "inherit" its tracing state
from the global state array. That is, if *any* existing vCPU has an
event enabled, new vCPUs will have too.
Signed-off-by: NLluís Vilanova <vilanova@ac.upc.edu>
Message-id: 147428970768.15111.7664565956870423529.stgit@fimbulvetr.bsc.es
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Removes the event state array used for early initialization. Since only
events with the "vcpu" property need a late initialization fixup,
threats their initialization specially.

Assumes that the user won't touch the state of "vcpu" events between
early and late initialization (e.g., through QMP).
Signed-off-by: NLluís Vilanova <vilanova@ac.upc.edu>
Message-id: 147194273191.26836.14423079546263831356.stgit@fimbulvetr.bsc.es
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Each vCPU gets a 'trace_dstate' bitmap to control the per-vCPU dynamic
tracing state of events with the 'vcpu' property.
Signed-off-by: NLluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

A new event attribute 'cpu_id' is added to have a separate ID
space ('TRACE_VCPU_*') for all events with the 'vcpu' property.

These are later used to identify which events are enabled on each vCPU.
Signed-off-by: NLluís Vilanova <vilanova@ac.upc.edu>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Cleaned up with scripts/clean-header-guards.pl.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NRichard Henderson <rth@twiddle.net>

The patch also creates trace_opt_parse() helper in trace/control.c to reuse
this code in next patches for qemu-nbd and qemu-io.

The patch also makes trace_init_events() static, as this call is not used
outside the module anymore.
Signed-off-by: NDenis V. Lunev <den@openvz.org>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Message-id: 1466174654-30130-4-git-send-email-den@openvz.org
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Re-run scripts/clean-includes to apply the previous commit's
corrections and updates.  Besides redundant qemu/typedefs.h, this only
finds a redundant config-host.h include in ui/egl-helpers.c.  No idea
how that escaped the previous runs.

Some manual whitespace trimming around dropped includes squashed in.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@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: NLluís Vilanova <vilanova@ac.upc.edu>
Message-id: 145641861797.30295.6991314023181842105.stgit@localhost
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Print a list of trace points
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NDenis V. Lunev <den@openvz.org>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Message-id: 1452174932-28657-7-git-send-email-den@openvz.org
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Allow enabling events without going through a file, for example:

   qemu-system-x86_64 -trace bdrv_aio_writev -trace bdrv_aio_readv

or with globbing too:

   qemu-system-x86_64 -trace 'bdrv_aio_*'

if an appropriate backend is enabled (simple, stderr, ftrace).
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NDenis V. Lunev <den@openvz.org>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Message-id: 1452174932-28657-6-git-send-email-den@openvz.org
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

This is cleaner, and improves error reporting with -daemonize.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NDenis V. Lunev <den@openvz.org>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Message-id: 1452174932-28657-4-git-send-email-den@openvz.org
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

This is cleaner and has two advantages.  First, it improves error
reporting with -daemonize.  Second, multiple "-trace events" options
now cumulate.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NDenis V. Lunev <den@openvz.org>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Message-id: 1452174932-28657-3-git-send-email-den@openvz.org
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

This is more cache friendly on the fast path, where we already have
the event id available.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

Signed-off-by: NLluís Vilanova <vilanova@ac.upc.edu>
Message-id: 20140825112002.31112.60143.stgit@fimbulvetr.bsc.es
Signed-off-by: NStefan 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: NLluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

This interface decouples event obtaining from interaction.

Events can be obtained through three different methods:

* identifier
* name
* simple wildcard pattern
Signed-off-by: NLluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

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: NLluís Vilanova <vilanova@ac.upc.edu>

Generalize the 'st_print_trace_events' and 'st_change_trace_event_state' into
backend-specific 'trace_print_events' and 'trace_event_set_state' (respectively)
in the "trace/control.h" file.
Signed-off-by: NLluís Vilanova <vilanova@ac.upc.edu>

A default implementation for backend-specific routines is provided in
"trace/default.c", which backends can override by setting "trace_default=no" in
"configure".
Signed-off-by: NLluís Vilanova <vilanova@ac.upc.edu>