Commit Graph

28 Commits

Author SHA1 Message Date
Stefan Hajnoczi d87aa13803 trace: add trace_event_get_state_backends()
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: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170731140718.22010-3-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-08-01 12:13:07 +01:00
Lluís Vilanova 61a67f71dd exec: [tcg] Use different TBs according to the vCPU's dynamic tracing state
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: Lluís Vilanova <vilanova@ac.upc.edu>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-id: 149915775266.6295.10060144081246467690.stgit@frigg.lan
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-07-17 13:11:05 +01:00
Lluís Vilanova 82e95ec847 trace: Fix dynamic event state on vCPU hot-unplug
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: Lluís Vilanova <vilanova@ac.upc.edu>
Message-id: 148278748055.1404.1570530281528619895.stgit@fimbulvetr.bsc.es
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-01-16 13:40:56 +00:00
Daniel P. Berrange 347701879c trace: get rid of generated-events.h/generated-events.c
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: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-17-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-10-12 09:54:52 +02:00
Daniel P. Berrange b7d48952c3 trace: dynamically allocate trace_dstate in CPUState
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: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-15-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-10-12 09:54:52 +02:00
Daniel P. Berrange fe4db84d49 trace: provide mechanism for registering trace events
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: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-14-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-10-12 09:52:50 +02:00
Daniel P. Berrange ef4c9fc854 trace: remove the TraceEventID and TraceEventVCPUID enums
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: Lluís Vilanova <vilanova@ac.upc.edu>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-11-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-10-12 09:35:54 +02:00
Daniel P. Berrange 599ab2f241 trace: remove some now unused functions
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: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-6-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-10-12 09:35:54 +02:00
Daniel P. Berrange 6a1b0f3aea trace: add trace event iterator APIs
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: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-4-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-10-12 09:35:53 +02:00
Lluís Vilanova 2bfe11c8fa trace: Properly initialize dynamic event states in hot-plugged vCPUs
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: Lluís Vilanova <vilanova@ac.upc.edu>
Message-id: 147428970768.15111.7664565956870423529.stgit@fimbulvetr.bsc.es
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-09-28 19:17:55 +01:00
Lluís Vilanova a4d50b1d2a trace: Remove 'trace_events_dstate_init'
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: Lluís Vilanova <vilanova@ac.upc.edu>
Message-id: 147194273191.26836.14423079546263831356.stgit@fimbulvetr.bsc.es
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-09-05 13:47:01 -04:00
Lluís Vilanova 4815185902 trace: Add per-vCPU tracing states for events with the 'vcpu' property
Each vCPU gets a 'trace_dstate' bitmap to control the per-vCPU dynamic
tracing state of events with the 'vcpu' property.

Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-18 18:23:12 +01:00
Lluís Vilanova 17f7ac75df trace: Identify events with the 'vcpu' property
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: Lluís Vilanova <vilanova@ac.upc.edu>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-18 18:13:54 +01:00
Markus Armbruster 175de52487 Clean up decorations and whitespace around header guards
Cleaned up with scripts/clean-header-guards.pl.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
2016-07-12 16:20:46 +02:00
Denis V. Lunev e9e0bb2af2 trace: move qemu_trace_opts to trace/control.c
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: Denis V. Lunev <den@openvz.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan 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: Stefan Hajnoczi <stefanha@redhat.com>
2016-06-28 21:14:12 +01:00
Markus Armbruster 14b6d44d47 Use scripts/clean-includes to drop redundant qemu/typedefs.h
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: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-22 22:20:16 +01:00
Lluís Vilanova 3d211d9f4d trace: Add 'vcpu' event property to trace guest vCPU
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>
2016-03-01 13:27:10 +00:00
Paolo Bonzini e9527dd399 trace: add "-trace help"
Print a list of trace points

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Message-id: 1452174932-28657-7-git-send-email-den@openvz.org
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-02-03 09:19:09 +00:00
Paolo Bonzini 10578a257d trace: add "-trace enable=..."
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: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Message-id: 1452174932-28657-6-git-send-email-den@openvz.org
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-02-03 09:19:09 +00:00
Paolo Bonzini 41fc57e44e trace: split trace_init_file out of trace_init_backends
This is cleaner, and improves error reporting with -daemonize.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Message-id: 1452174932-28657-4-git-send-email-den@openvz.org
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-02-03 09:19:09 +00:00
Paolo Bonzini 45bd0b41bd trace: split trace_init_events out of trace_init_backends
This is cleaner and has two advantages.  First, it improves error
reporting with -daemonize.  Second, multiple "-trace events" options
now cumulate.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Message-id: 1452174932-28657-3-git-send-email-den@openvz.org
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-02-03 09:19:09 +00:00
Paolo Bonzini 585ec7273e trace: track enabled events in a separate array
This is more cache friendly on the fast path, where we already have
the event id available.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-02-03 09:19:09 +00:00
Lluís Vilanova 14101d028d trace: [hmp] Reimplement "trace-event" and "info trace-events" using QMP
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Message-id: 20140825112002.31112.60143.stgit@fimbulvetr.bsc.es
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-26 09:34:38 +01:00
Lluís Vilanova 5b808275f3 trace: Multi-backend tracing
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>
2014-06-09 15:43:40 +02:00
Lluís Vilanova b1bae816c4 trace: Provide a detailed event control interface
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>
2013-03-28 14:19:57 +01:00
Lluís 23d15e860b trace: add "-trace events" argument to control initial state
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>
2011-09-01 10:34:54 +01:00
Lluís fc76410539 trace: separate trace event control and query routines from the simple backend
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: Lluís Vilanova <vilanova@ac.upc.edu>
2011-09-01 10:34:54 +01:00
Lluís e4858974ec trace: avoid conditional code compilation during option parsing
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: Lluís Vilanova <vilanova@ac.upc.edu>
2011-09-01 10:34:53 +01:00