| Message ID | 1493044126-21488-1-git-send-email-joserz@linux.vnet.ibm.com |
|---|---|
| State | New |
| Headers | show |
On Mon, 04/24 11:28, Jose Ricardo Ziviani wrote: > 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 to see 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'd 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> > --- > util/qemu-thread-posix.c | 5 +++++ > util/trace-events | 4 ++++ > 2 files changed, 9 insertions(+) > > diff --git a/util/qemu-thread-posix.c b/util/qemu-thread-posix.c > index 73e3a0e..909c2ac 100644 > --- a/util/qemu-thread-posix.c > +++ b/util/qemu-thread-posix.c > @@ -14,6 +14,7 @@ > #include "qemu/thread.h" > #include "qemu/atomic.h" > #include "qemu/notify.h" > +#include "trace.h" > > static bool name_threads; > > @@ -60,6 +61,8 @@ void qemu_mutex_lock(QemuMutex *mutex) > err = pthread_mutex_lock(&mutex->lock); > if (err) > error_exit(err, __func__); > + > + trace_qemu_mutex_lock((void *)&mutex->lock); You don't need these casts as the parameter type is void * which accepts any pointers. > } > > int qemu_mutex_trylock(QemuMutex *mutex) > @@ -74,6 +77,8 @@ void qemu_mutex_unlock(QemuMutex *mutex) > err = pthread_mutex_unlock(&mutex->lock); > if (err) > error_exit(err, __func__); > + > + trace_qemu_mutex_unlock((void *)&mutex->lock); > } > > void qemu_rec_mutex_init(QemuRecMutex *mutex) > diff --git a/util/trace-events b/util/trace-events > index b44ef4f..65c33fe 100644 > --- a/util/trace-events > +++ b/util/trace-events > @@ -55,3 +55,7 @@ lockcnt_futex_wait_prepare(const void *lockcnt, int expected, int new) "lockcnt > lockcnt_futex_wait(const void *lockcnt, int val) "lockcnt %p waiting on %d" > lockcnt_futex_wait_resume(const void *lockcnt, int new) "lockcnt %p after wait: %d" > lockcnt_futex_wake(const void *lockcnt) "lockcnt %p waking up one waiter" > + > +# util/qemu-thread-posix.c > +qemu_mutex_lock(void *qemu_global_mutex) "locked mutex %p" > +qemu_mutex_unlock(void *qemu_global_mutex) "unlocked mutex %p" Parameter name is slightly misleading, maybe s/qemu_global_mutex/lock/ for both lines? Fam
On Mon, Apr 24, 2017 at 10:45:52PM +0800, Fam Zheng wrote: > On Mon, 04/24 11:28, Jose Ricardo Ziviani wrote: > > 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 to see 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'd 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> > > --- > > util/qemu-thread-posix.c | 5 +++++ > > util/trace-events | 4 ++++ > > 2 files changed, 9 insertions(+) > > > > diff --git a/util/qemu-thread-posix.c b/util/qemu-thread-posix.c > > index 73e3a0e..909c2ac 100644 > > --- a/util/qemu-thread-posix.c > > +++ b/util/qemu-thread-posix.c > > @@ -14,6 +14,7 @@ > > #include "qemu/thread.h" > > #include "qemu/atomic.h" > > #include "qemu/notify.h" > > +#include "trace.h" > > > > static bool name_threads; > > > > @@ -60,6 +61,8 @@ void qemu_mutex_lock(QemuMutex *mutex) > > err = pthread_mutex_lock(&mutex->lock); > > if (err) > > error_exit(err, __func__); > > + > > + trace_qemu_mutex_lock((void *)&mutex->lock); > > You don't need these casts as the parameter type is void * which accepts any > pointers. OK > > > } > > > > int qemu_mutex_trylock(QemuMutex *mutex) > > @@ -74,6 +77,8 @@ void qemu_mutex_unlock(QemuMutex *mutex) > > err = pthread_mutex_unlock(&mutex->lock); > > if (err) > > error_exit(err, __func__); > > + > > + trace_qemu_mutex_unlock((void *)&mutex->lock); > > } > > > > void qemu_rec_mutex_init(QemuRecMutex *mutex) > > diff --git a/util/trace-events b/util/trace-events > > index b44ef4f..65c33fe 100644 > > --- a/util/trace-events > > +++ b/util/trace-events > > @@ -55,3 +55,7 @@ lockcnt_futex_wait_prepare(const void *lockcnt, int expected, int new) "lockcnt > > lockcnt_futex_wait(const void *lockcnt, int val) "lockcnt %p waiting on %d" > > lockcnt_futex_wait_resume(const void *lockcnt, int new) "lockcnt %p after wait: %d" > > lockcnt_futex_wake(const void *lockcnt) "lockcnt %p waking up one waiter" > > + > > +# util/qemu-thread-posix.c > > +qemu_mutex_lock(void *qemu_global_mutex) "locked mutex %p" > > +qemu_mutex_unlock(void *qemu_global_mutex) "unlocked mutex %p" > > Parameter name is slightly misleading, maybe s/qemu_global_mutex/lock/ for both > lines? Great! I'll change it and send a v2. Thank for your review! > > Fam >
diff --git a/util/qemu-thread-posix.c b/util/qemu-thread-posix.c index 73e3a0e..909c2ac 100644 --- a/util/qemu-thread-posix.c +++ b/util/qemu-thread-posix.c @@ -14,6 +14,7 @@ #include "qemu/thread.h" #include "qemu/atomic.h" #include "qemu/notify.h" +#include "trace.h" static bool name_threads; @@ -60,6 +61,8 @@ void qemu_mutex_lock(QemuMutex *mutex) err = pthread_mutex_lock(&mutex->lock); if (err) error_exit(err, __func__); + + trace_qemu_mutex_lock((void *)&mutex->lock); } int qemu_mutex_trylock(QemuMutex *mutex) @@ -74,6 +77,8 @@ void qemu_mutex_unlock(QemuMutex *mutex) err = pthread_mutex_unlock(&mutex->lock); if (err) error_exit(err, __func__); + + trace_qemu_mutex_unlock((void *)&mutex->lock); } void qemu_rec_mutex_init(QemuRecMutex *mutex) diff --git a/util/trace-events b/util/trace-events index b44ef4f..65c33fe 100644 --- a/util/trace-events +++ b/util/trace-events @@ -55,3 +55,7 @@ lockcnt_futex_wait_prepare(const void *lockcnt, int expected, int new) "lockcnt lockcnt_futex_wait(const void *lockcnt, int val) "lockcnt %p waiting on %d" lockcnt_futex_wait_resume(const void *lockcnt, int new) "lockcnt %p after wait: %d" lockcnt_futex_wake(const void *lockcnt) "lockcnt %p waking up one waiter" + +# util/qemu-thread-posix.c +qemu_mutex_lock(void *qemu_global_mutex) "locked mutex %p" +qemu_mutex_unlock(void *qemu_global_mutex) "unlocked mutex %p"
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 to see 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'd 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> --- util/qemu-thread-posix.c | 5 +++++ util/trace-events | 4 ++++ 2 files changed, 9 insertions(+)