[PATCH v9 00/13] TCG code quality tracking and perf integration

[Alex Bennée]

Hi,

These are the bits of Vanderson's GSoC project which I think are ready
for merge(^) and would like get up-streamed before the code freeze
kicks in. It effectively removes the CONFIG_PROFILER support in favour
of a more dynamic and configurable TB Statistics subsystem. While not
in use it has no impact on the system apart a small amount of wasted
space in the TCGContext for each thread which is used to collect stats
during translation. When in use a TBStats structure is created for
each set of TBs that have the same address/flags combination. The most
basic tracking involves counting executions of each TB. You can also
enable JIT stats and sort by features such as spill count and
host/guest expansion ration.

For full performance analysis you can use -perf to output a JIT dump
that is compatible with the linux perf tool. This allows you to see
exactly which TBs are responsible for the majority of real execution
time. With the additional TB stats involved it will also include basic
information about the quality of that code.

The main changes from Vanderson's last post apart from general
clean-ups and g_autoptr'ing is I've dropped the "cfg" and "coverset"
commands. I dropped "cfg" because I wasn't happy about it navigated
the next TB in the chain. "coverset" tends to dump quite a lot of TBs
on a full system emulation so I wanted to think about a slightly
smoother UI experience.

^ and finally I think I'll also drop the "tb" command for the next
iteration because although useful it fails when the guest has
un-mapped pages and results in a exception getting delivered to the
guest which is less than ideal. See the comments for get_code_string.
However I've left it in this iteration so you can see a taste of the
future.

There are more notes on the project at the wiki page:

  https://wiki.qemu.org/Features/TCGCodeQuality

Please review.

Alex Bennée (2):
  tb-stats: reset the tracked TBs on a tb_flush
  configure: remove the final bits of --profiler support

Vanderson M. do Rosario (11):
  accel/tcg: introduce TBStatistics structure
  accel: collecting TB execution count
  accel: collecting JIT statistics
  accel: replacing part of CONFIG_PROFILER with TBStats
  accel: adding TB_JIT_TIME and full replacing CONFIG_PROFILER
  debug: add -d tb_stats to control TBStatistics collection:
  monitor: adding tb_stats hmp command
  Adding info [tb-list|tb] commands to HMP (WIP)
  tb-stats: dump hot TBs at the end of the execution
  accel/tcg: adding integration with linux perf
  tb-stats: adding TBStatistics info into perf dump

 accel/tcg/Makefile.objs       |   4 +-
 accel/tcg/cpu-exec.c          |   4 +
 accel/tcg/perf/Makefile.objs  |   1 +
 accel/tcg/perf/jitdump.c      | 206 +++++++++++
 accel/tcg/perf/jitdump.h      |  36 ++
 accel/tcg/tb-stats.c          | 662 ++++++++++++++++++++++++++++++++++
 accel/tcg/tcg-runtime.c       |   7 +
 accel/tcg/tcg-runtime.h       |   2 +
 accel/tcg/translate-all.c     | 173 +++++++--
 accel/tcg/translator.c        |   4 +
 configure                     |   8 -
 cpus.c                        |  14 +-
 disas.c                       |  31 +-
 docs/devel/tcg.rst            |  15 +
 hmp-commands-info.hx          |  16 +
 hmp-commands.hx               |  17 +
 include/exec/exec-all.h       |  15 +-
 include/exec/gen-icount.h     |  10 +
 include/exec/tb-context.h     |  12 +
 include/exec/tb-hash.h        |   7 +
 include/exec/tb-stats-dump.h  |  21 ++
 include/exec/tb-stats-flags.h |  31 ++
 include/exec/tb-stats.h       | 165 +++++++++
 include/qemu-common.h         |   3 +
 include/qemu/log-for-trace.h  |   4 +
 include/qemu/log.h            |   3 +
 include/qemu/timer.h          |   5 +-
 linux-user/exit.c             |   2 +
 linux-user/main.c             |   7 +
 monitor/misc.c                | 127 +++++--
 os-posix.c                    |   5 +
 qemu-options.hx               |  11 +
 stubs/Makefile.objs           |   1 +
 stubs/tb-stats.c              |  32 ++
 tcg/tcg.c                     | 221 +++---------
 tcg/tcg.h                     |  34 +-
 util/log.c                    |  89 ++++-
 vl.c                          |  10 +-
 38 files changed, 1727 insertions(+), 288 deletions(-)
 create mode 100644 accel/tcg/perf/Makefile.objs
 create mode 100644 accel/tcg/perf/jitdump.c
 create mode 100644 accel/tcg/perf/jitdump.h
 create mode 100644 accel/tcg/tb-stats.c
 create mode 100644 include/exec/tb-stats-dump.h
 create mode 100644 include/exec/tb-stats-flags.h
 create mode 100644 include/exec/tb-stats.h
 create mode 100644 stubs/tb-stats.c

-- 
2.20.1