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| author | Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com> | 2017-04-24 14:19:58 -0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2017-05-05 12:09:59 +0200 |
| commit | 31f5a726b59bda5580e2f9413867893501dd7d93 (patch) | |
| tree | 33c91bb25066d13fc9f79aae3ca2379465dcbe51 /qapi/qobject-input-visitor.c | |
| parent | f68826989cd4d1217797251339579c57b3c0934e (diff) | |
| download | focaccia-qemu-31f5a726b59bda5580e2f9413867893501dd7d93.tar.gz focaccia-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 'qapi/qobject-input-visitor.c')
0 files changed, 0 insertions, 0 deletions