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| author | Jose Ricardo Ziviani | 2017-04-24 19:19:58 +0200 |
|---|---|---|
| committer | Paolo Bonzini | 2017-05-05 12:09:59 +0200 |
| commit | 31f5a726b59bda5580e2f9413867893501dd7d93 (patch) | |
| tree | 33c91bb25066d13fc9f79aae3ca2379465dcbe51 /scripts | |
| parent | vmw_pvscsi: check message ring page count at initialisation (diff) | |
| download | qemu-31f5a726b59bda5580e2f9413867893501dd7d93.tar.gz qemu-31f5a726b59bda5580e2f9413867893501dd7d93.tar.xz qemu-31f5a726b59bda5580e2f9413867893501dd7d93.zip | |
trace: add qemu mutex lock and unlock trace events
These trace events were very useful to help me to understand and find a
reordering issue in vfio, for example:
qemu_mutex_lock locked mutex 0x10905ad8
vfio_region_write (0001:03:00.0:region1+0xc0, 0x2020c, 4)
qemu_mutex_unlock unlocked mutex 0x10905ad8
qemu_mutex_lock locked mutex 0x10905ad8
vfio_region_write (0001:03:00.0:region1+0xc4, 0xa0000, 4)
qemu_mutex_unlock unlocked mutex 0x10905ad8
that also helped me to see the desired result after the fix:
qemu_mutex_lock locked mutex 0x10905ad8
vfio_region_write (0001:03:00.0:region1+0xc0, 0x2000c, 4)
vfio_region_write (0001:03:00.0:region1+0xc4, 0xb0000, 4)
qemu_mutex_unlock unlocked mutex 0x10905ad8
So it could be a good idea to have these traces implemented. It's worth
mentioning that they should be surgically enabled during the debugging,
otherwise it can flood the trace logs with lock/unlock messages.
How to use it:
trace-event qemu_mutex_lock on|off
trace-event qemu_mutex_unlock on|off
or
trace-event qemu_mutex* on|off
Signed-off-by: Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com>
Message-Id: <1493054398-26013-1-git-send-email-joserz@linux.vnet.ibm.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
[Also handle trylock, cond_wait and win32; trace "unlocked" while still
in the critical section, so that "unlocked" always comes before the
next "locked" tracepoint. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'scripts')
0 files changed, 0 insertions, 0 deletions