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[Qemu-devel] [PATCH v5 00/20] Refactor trace to allow modular build
From: |
Daniel P. Berrange |
Subject: |
[Qemu-devel] [PATCH v5 00/20] Refactor trace to allow modular build |
Date: |
Wed, 28 Sep 2016 14:08:03 +0100 |
These patches were previously posted as part of my giant
trace events modular build series
v1: https://lists.gnu.org/archive/html/qemu-devel/2016-08/msg01714.html
v2: https://lists.gnu.org/archive/html/qemu-devel/2016-09/msg03335.html
v3: https://lists.gnu.org/archive/html/qemu-devel/2016-09/msg04282.html
v4: https://lists.gnu.org/archive/html/qemu-devel/2016-09/msg05467.html
This series does all the refactoring required to support a fully
modular build of the trace probe points, but does not actually
convert anything to use it. The 40+ patches to convert each subdir
to use modular build will only be posted again, once the refactoring
is reviewed & queued, in order to avoid patch-bombing the list
more than is needed. The full series is visible at
https://github.com/berrange/qemu/tree/trace-events-3
The key problem being tackled by this series is the assumption
that there is a single statically declared enum which provides
globally unique event IDs. Inside QEMU the event IDs were used
as list indexes into the 'trace_events' array, while the event
VCPU IDs were used as bitmap indexes in trace_dstate against
the CPUState struct. Externally to QEMU, the event IDs were
also written in the simpletrace binary data format and used
to lookup the entry in the trace-events file afterwards.
Inside QEMU the refactoring work managed to remove all need
for event IDs for purposes of 'trace_events' array lookups.
Instead we now have global variables per-event which can be
referenced directly.
When QEMU starts up and the various event groups are registered,
we now dynamically assign event IDs and VCPU IDs to each event.
This removes the limitation in the v1 posting that all vCPU
events had to be in one file. We also removed the limitation
on the total number of vCPU events. So there is no regression
in functionality of VCPU event support compared to current
GIT master.
Since the event IDs are allocated dynamically at runtime,
the simpletrace.py script cannot assume they map directly
to the 'trace-events' file entries. Thus, the simpletrace
binary format is extended to include a record type that
maps trace event IDs to trace event names. While it would
be possible to take this even further and make the
simpletrace binary format 100% self-describing this is left
as an exercise for future developers, as it is not a
pre-requisite for this modular build.
While some of the intermediate patches may seem pointless
on their own, they exist in order to facilitate the review
of later patches by ensuring each patch does the minimum
possible refactoring work.
Changed in v5:
- Use single '_' instead of double/triple '_' in
constants (Lluís)
- Use more pythonic loop iterator (Lluís)
- Misc typos (Lluís/Stefan)
- Fix filtering of QMP trace events (Lluís)
- Fix some new mistakes in trace-events in master
Changed in v4:
- Misc typos / indentation (Lluís, Eric)
- Simplify do_trace_enable_events (Lluís)
- Use Event.api() in more places (Lluís)
- Actually delete events_{h,c}.py (Lluís)
- Use bitmap_new() for allocation (Lluís)
- Dont use .git to make relative path (Lluís)
Changed in v3:
- Change simpletrace format to write a mapping of
IDs to names
- Declare a TraceEvent variable per event, instead
of just an array
- Make 'trace_events' array be 'TraceEvent **'
instead of 'TraceEvent *'
- Fix infinite loop in iterators due to bad
fix in v2 posting.
- Dynamically allocate the trace_dstate variable
in CPUState based on actual number of vcpu events
registered at runtime
- Push logic for determining group name into the
tracetool program
- Fix to ftrace to make it more practical for users
who sometimes run QEMU as non-root.
- Get rid of TraceEventID/VCPUID enums entirely
Changed in v2:
- Fixed filtering of events on first call of
iterator_next (Stefan)
- Switch from size_t to uint32_t for event ID
type (Paolo/Stefan)
- Replace global 'dstate' array with individual
variables (Lluís)
Daniel P. Berrange (20):
trace: move colo trace events to net/ sub-directory
trace: remove double-underscore in event name
trace: add trace event iterator APIs
trace: convert code to use event iterators
trace: remove some now unused functions
trace: remove global 'uint16 dstate[]' array
trace: remove duplicate control.h includes in generated-tracers.h
trace: break circular dependency in event-internal.h
trace: give each trace event a named TraceEvent struct
trace: remove the TraceEventID and TraceEventVCPUID enums
trace: emit name <-> ID mapping in simpletrace header
trace: don't abort qemu if ftrace can't be initialized
trace: provide mechanism for registering trace events
trace: dynamically allocate trace_dstate in CPUState
trace: dynamically allocate event IDs at runtime
trace: get rid of generated-events.h/generated-events.c
trace: rename _read_events to read_events
trace: push reading of events up a level to tracetool main
trace: pass trace-events to tracetool as a positional param
trace: introduce a formal group name for trace events
Makefile | 3 -
Makefile.target | 6 +-
hw/scsi/spapr_vscsi.c | 2 +-
hw/scsi/trace-events | 2 +-
include/qemu/module.h | 2 +
include/qom/cpu.h | 9 +-
include/trace-tcg.h | 1 -
include/trace.h | 1 -
monitor.c | 26 +++--
net/trace-events | 16 +++
qemu-img.c | 1 +
qemu-io.c | 1 +
qemu-nbd.c | 1 +
qom/cpu.c | 8 +-
scripts/simpletrace.py | 56 +++++++---
scripts/tracetool.py | 20 +++-
scripts/tracetool/__init__.py | 28 +++--
scripts/tracetool/backend/__init__.py | 12 +-
scripts/tracetool/backend/dtrace.py | 4 +-
scripts/tracetool/backend/ftrace.py | 6 +-
scripts/tracetool/backend/log.py | 7 +-
scripts/tracetool/backend/simple.py | 12 +-
scripts/tracetool/backend/syslog.py | 5 +-
scripts/tracetool/backend/ust.py | 4 +-
scripts/tracetool/format/__init__.py | 4 +-
scripts/tracetool/format/c.py | 56 ++++++++--
scripts/tracetool/format/d.py | 2 +-
scripts/tracetool/format/events_c.py | 44 --------
scripts/tracetool/format/events_h.py | 60 ----------
scripts/tracetool/format/h.py | 37 +++++--
scripts/tracetool/format/simpletrace_stap.py | 26 ++++-
scripts/tracetool/format/stap.py | 2 +-
scripts/tracetool/format/tcg_h.py | 2 +-
scripts/tracetool/format/tcg_helper_c.py | 2 +-
scripts/tracetool/format/tcg_helper_h.py | 2 +-
scripts/tracetool/format/tcg_helper_wrapper_h.py | 2 +-
scripts/tracetool/format/ust_events_c.py | 2 +-
scripts/tracetool/format/ust_events_h.py | 9 +-
stubs/trace-control.c | 9 +-
trace-events | 16 ---
trace/Makefile.objs | 46 +++-----
trace/control-internal.h | 48 +++-----
trace/control-target.c | 22 ++--
trace/control.c | 134 ++++++++++++++---------
trace/control.h | 112 +++++++------------
trace/event-internal.h | 18 ++-
trace/ftrace.c | 6 +
trace/qmp.c | 16 ++-
trace/simple.c | 41 ++++++-
trace/simple.h | 6 +-
vl.c | 2 +
51 files changed, 501 insertions(+), 458 deletions(-)
delete mode 100644 scripts/tracetool/format/events_c.py
delete mode 100644 scripts/tracetool/format/events_h.py
--
2.7.4
- [Qemu-devel] [PATCH v5 00/20] Refactor trace to allow modular build,
Daniel P. Berrange <=
- [Qemu-devel] [PATCH v5 02/20] trace: remove double-underscore in event name, Daniel P. Berrange, 2016/09/28
- [Qemu-devel] [PATCH v5 04/20] trace: convert code to use event iterators, Daniel P. Berrange, 2016/09/28
- [Qemu-devel] [PATCH v5 01/20] trace: move colo trace events to net/ sub-directory, Daniel P. Berrange, 2016/09/28
- [Qemu-devel] [PATCH v5 05/20] trace: remove some now unused functions, Daniel P. Berrange, 2016/09/28
- [Qemu-devel] [PATCH v5 03/20] trace: add trace event iterator APIs, Daniel P. Berrange, 2016/09/28
- [Qemu-devel] [PATCH v5 08/20] trace: break circular dependency in event-internal.h, Daniel P. Berrange, 2016/09/28
- [Qemu-devel] [PATCH v5 06/20] trace: remove global 'uint16 dstate[]' array, Daniel P. Berrange, 2016/09/28
- [Qemu-devel] [PATCH v5 12/20] trace: don't abort qemu if ftrace can't be initialized, Daniel P. Berrange, 2016/09/28