From: "Daniel P. Berrangé" <berrange@redhat.com>
To: qemu-devel@nongnu.org
Cc: "Stefan Hajnoczi" <stefanha@redhat.com>,
"Daniel P. Berrangé" <berrange@redhat.com>
Subject: [PATCH 00/20] trace: bugfixes, cleanups and optimizations
Date: Thu, 1 Oct 2026 16:12:08 +0100 [thread overview]
Message-ID: <20261001151228.3373747-1-berrange@redhat.com> (raw)
This series started off with fixing some compile failures seen
with dtrace and ust backends, and got somewhat out of hand as
I looked more deeply at the trace code. So it ended up doing
various bits of code cleanup and memory usage optimizations.
The optimizations aren't huge against each individual binaries.
There are too many scenarios to show the full set, but here
are some binary size examples
The current git master baseline for different enabled
backends on the x86_64 emulator:
nop 88546360
dtrace 90604496
ftrace 93265944
log 93799528
syslog 93962704
simple 97064528
ust 162999944
dtrace,ftrace,log,syslog,simple,ust 174438088
'ust' has insanely high overhead in terms of binary sizes,
inexplicably insane.
'ftrace/log/syslog' are all similar because their overhead
is dominated by the printf() format strings which are
identical in all.
'simple' is a bit worse because of the helper functions we
must generated for each probe
After this series is applied the results for x86_64 are
nop 88510248
dtrace 90576160
ftrace 93156320
log 93735064
syslog 93853480
simple 97050856
ust 162957256
dtrace,ftrace,log,syslog,simple,ust 174431128
IOW, for 'dtrace', we save 28k, for 'log' we save 62k
For the aarch64 binary, we see bigger saving in some
cases:
baseline dtrace 127610144
baseline log 131050320
trace dtrace 127459264
trace log 130998872
IOW, for 'dtrace' we save 150k, for 'log' we only save
50k. No clue why the saving is not so significant for
the 'log' backend but not a big deal.
Daniel P. Berrangé (20):
osdep: add 'ignore_value(x)' macro
trace: use 'ignore_value()' instead of a dummy variable
trace: fix handling of char** in UST backend
hw/xen: replace "long unsigned int" with "unsigned long " for dtrace
trace: block use of "long int" for dtrace
trace: drop unused trace_event_set_state_dynamic_init()
trace: remove obsolete references to vcpu property
trace: drop 'id' from TraceEvent struct when not required
trace: change "DSTATE" variables from uint16_t to uint8_t
trace: add testing of 'nop' trace backend
trace: don't emit TraceEvent structs when 'nop' backend is used
trace: add test of generation with all backends enabled
trace: remove redundant headers from simple trace backend code
audio: remove mistaken use of trace_event_get_state()
hw/ppc: remove mistaken use of trace_event_get_state()
trace: include qemu_loglevel_mask(LOG_TRACE) in guard
trace: remove "disable" property from trace files
trace: stop tracking static disabled state
trace: remove parsing of "disable" event property
trace: remove 'trace_event_get_state' wrapper
audio/audio-mixeng-be.c | 2 +-
hw/display/trace-events | 2 +-
hw/ppc/vof.c | 13 +--
hw/xen/trace-events | 4 +-
include/qemu/osdep.h | 8 ++
monitor/qmp.c | 4 +-
qapi/trace.json | 5 +-
scripts/tracetool/__init__.py | 32 ++----
scripts/tracetool/backend/__init__.py | 3 +-
scripts/tracetool/backend/dtrace.py | 2 -
scripts/tracetool/backend/log.py | 3 +-
scripts/tracetool/backend/simple.py | 4 +-
scripts/tracetool/format/c.py | 74 +++++++-------
scripts/tracetool/format/d.py | 3 -
scripts/tracetool/format/h.py | 42 ++++----
scripts/tracetool/format/log_stap.py | 3 -
scripts/tracetool/format/rs.py | 30 +++---
scripts/tracetool/format/simpletrace_stap.py | 3 -
scripts/tracetool/format/stap.py | 3 -
scripts/tracetool/format/ust_events_c.py | 3 -
scripts/tracetool/format/ust_events_h.py | 7 +-
stubs/trace-control.c | 6 --
target/hppa/trace-events | 28 ++---
tests/tracetool/all.c | 61 +++++++++++
tests/tracetool/all.d | 10 ++
tests/tracetool/all.h | 102 +++++++++++++++++++
tests/tracetool/all.log-stap | 15 +++
tests/tracetool/all.rs | 90 ++++++++++++++++
tests/tracetool/all.simpletrace-stap | 16 +++
tests/tracetool/all.stap | 14 +++
tests/tracetool/all.ust-events-c | 14 +++
tests/tracetool/all.ust-events-h | 56 ++++++++++
tests/tracetool/dtrace.c | 10 +-
tests/tracetool/dtrace.h | 6 +-
tests/tracetool/dtrace.rs | 6 +-
tests/tracetool/ftrace.c | 10 +-
tests/tracetool/ftrace.h | 14 ++-
tests/tracetool/ftrace.rs | 6 +-
tests/tracetool/log.c | 10 +-
tests/tracetool/log.h | 20 ++--
tests/tracetool/log.rs | 6 +-
tests/tracetool/meson.build | 4 +-
tests/tracetool/nop.c | 7 ++
tests/tracetool/nop.h | 25 +++++
tests/tracetool/nop.rs | 51 ++++++++++
tests/tracetool/simple.c | 12 +--
tests/tracetool/simple.h | 10 +-
tests/tracetool/simple.rs | 6 +-
tests/tracetool/syslog.c | 10 +-
tests/tracetool/syslog.h | 14 ++-
tests/tracetool/syslog.rs | 6 +-
tests/tracetool/tracetool-test.py | 12 ++-
tests/tracetool/ust.c | 10 +-
tests/tracetool/ust.h | 6 +-
trace/control-internal.h | 8 +-
trace/control-target.c | 29 ------
trace/control.c | 19 +---
trace/control.h | 43 +-------
trace/event-internal.h | 19 +---
trace/ftrace.c | 3 +-
trace/qmp.c | 47 +++------
trace/simple.c | 9 +-
62 files changed, 704 insertions(+), 396 deletions(-)
create mode 100644 tests/tracetool/all.c
create mode 100644 tests/tracetool/all.d
create mode 100644 tests/tracetool/all.h
create mode 100644 tests/tracetool/all.log-stap
create mode 100644 tests/tracetool/all.rs
create mode 100644 tests/tracetool/all.simpletrace-stap
create mode 100644 tests/tracetool/all.stap
create mode 100644 tests/tracetool/all.ust-events-c
create mode 100644 tests/tracetool/all.ust-events-h
create mode 100644 tests/tracetool/nop.c
create mode 100644 tests/tracetool/nop.h
create mode 100644 tests/tracetool/nop.rs
--
2.55.0
next reply other threads:[~2026-10-01 15:13 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-01 15:12 Daniel P. Berrangé [this message]
2026-10-01 15:12 ` [PATCH 01/20] osdep: add 'ignore_value(x)' macro Daniel P. Berrangé
2026-10-01 15:12 ` [PATCH 02/20] trace: use 'ignore_value()' instead of a dummy variable Daniel P. Berrangé
2026-10-01 15:12 ` [PATCH 03/20] trace: fix handling of char** in UST backend Daniel P. Berrangé
2026-10-01 15:12 ` [PATCH 04/20] hw/xen: replace "long unsigned int" with "unsigned long " for dtrace Daniel P. Berrangé
2026-10-01 17:56 ` Philippe Mathieu-Daudé
2026-10-01 15:12 ` [PATCH 05/20] trace: block use of "long int" " Daniel P. Berrangé
2026-10-01 15:12 ` [PATCH 06/20] trace: drop unused trace_event_set_state_dynamic_init() Daniel P. Berrangé
2026-10-01 15:12 ` [PATCH 07/20] trace: remove obsolete references to vcpu property Daniel P. Berrangé
2026-10-01 17:58 ` Philippe Mathieu-Daudé
2026-10-01 15:12 ` [PATCH 08/20] trace: drop 'id' from TraceEvent struct when not required Daniel P. Berrangé
2026-10-01 15:12 ` [PATCH 09/20] trace: change "DSTATE" variables from uint16_t to uint8_t Daniel P. Berrangé
2026-10-01 15:12 ` [PATCH 10/20] trace: add testing of 'nop' trace backend Daniel P. Berrangé
2026-10-01 15:12 ` [PATCH 11/20] trace: don't emit TraceEvent structs when 'nop' backend is used Daniel P. Berrangé
2026-10-01 15:12 ` [PATCH 12/20] trace: add test of generation with all backends enabled Daniel P. Berrangé
2026-10-01 15:12 ` [PATCH 13/20] trace: remove redundant headers from simple trace backend code Daniel P. Berrangé
2026-10-01 15:12 ` [PATCH 14/20] audio: remove mistaken use of trace_event_get_state() Daniel P. Berrangé
2026-10-01 18:00 ` Philippe Mathieu-Daudé
2026-10-01 19:14 ` marcandre.lureau
2026-10-02 7:12 ` Daniel P. Berrangé
2026-10-01 15:12 ` [PATCH 15/20] hw/ppc: " Daniel P. Berrangé
2026-10-01 18:01 ` Philippe Mathieu-Daudé
2026-10-01 15:12 ` [PATCH 16/20] trace: include qemu_loglevel_mask(LOG_TRACE) in guard Daniel P. Berrangé
2026-10-02 10:45 ` Paolo Bonzini
2026-10-02 11:03 ` Daniel P. Berrangé
2026-10-02 14:49 ` Paolo Bonzini
2026-10-05 12:08 ` Daniel P. Berrangé
2026-10-01 15:12 ` [PATCH 17/20] trace: remove "disable" property from trace files Daniel P. Berrangé
2026-10-01 15:12 ` [PATCH 18/20] trace: stop tracking static disabled state Daniel P. Berrangé
2026-10-01 19:14 ` marcandre.lureau
2026-10-02 9:22 ` Daniel P. Berrangé
2026-10-01 15:12 ` [PATCH 19/20] trace: remove parsing of "disable" event property Daniel P. Berrangé
2026-10-01 15:12 ` [PATCH 20/20] trace: remove 'trace_event_get_state' wrapper Daniel P. Berrangé
2026-10-01 19:14 ` [PATCH 00/20] trace: bugfixes, cleanups and optimizations marcandre.lureau
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