| Message ID | 1395322632-9139-1-git-send-email-bill.fischofer@linaro.org |
|---|---|
| State | Accepted, archived |
| Headers | show |
applied! thanks, Maxim. On 03/20/2014 05:37 PM, Bill Fischofer wrote: > Add odp_mem_barrier() before exit from odp_barrier_sync() > > Signed-off-by: Bill Fischofer <bill.fischofer@linaro.org> > --- > include/odp_barrier.h | 3 +- > platform/linux-generic/source/odp_barrier.c | 44 ++++++++++++++--------------- > 2 files changed, 22 insertions(+), 25 deletions(-) > > diff --git a/include/odp_barrier.h b/include/odp_barrier.h > index bb4a6c5..0a1404b 100644 > --- a/include/odp_barrier.h > +++ b/include/odp_barrier.h > @@ -28,8 +28,7 @@ extern "C" { > */ > typedef struct odp_barrier_t { > int count; > - odp_atomic_int_t in; > - odp_atomic_int_t out; > + odp_atomic_int_t bar; > } odp_barrier_t; > > > diff --git a/platform/linux-generic/source/odp_barrier.c b/platform/linux-generic/source/odp_barrier.c > index 64fbdb9..a82b294 100644 > --- a/platform/linux-generic/source/odp_barrier.c > +++ b/platform/linux-generic/source/odp_barrier.c > @@ -11,40 +11,38 @@ > void odp_barrier_init_count(odp_barrier_t *barrier, int count) > { > barrier->count = count; > - barrier->in = 0; > - barrier->out = count - 1; > + barrier->bar = 0; > odp_sync_stores(); > } > > +/* > + * Efficient barrier_sync - > + * > + * Barriers are initialized with a count of the number of callers > + * that must sync on the barrier before any may proceed. > + * > + * To avoid race conditions and to permit the barrier to be fully > + * reusable, the barrier value cycles between 0..2*count-1. When > + * synchronizing the wasless variable simply tracks which half of > + * the cycle the barrier was in upon entry. Exit is when the > + * barrier crosses to the other half of the cycle. > + */ > > void odp_barrier_sync(odp_barrier_t *barrier) > { > int count; > + int wasless; > > odp_sync_stores(); > + wasless = barrier->bar < barrier->count; > + count = odp_atomic_fetch_inc_int(&barrier->bar); > > - count = odp_atomic_fetch_inc_int(&barrier->in); > - > - if (count == barrier->count - 1) { > - /* If last thread, release others */ > - barrier->in = 0; > - odp_sync_stores(); > - > - /* Wait for others to exit */ > - while (barrier->out) > - odp_spin(); > - > - /* Ready, reset out counter */ > - barrier->out = barrier->count - 1; > - odp_sync_stores(); > - > + if (count == 2*barrier->count-1) { > + barrier->bar = 0; > } else { > - /* Wait for the last thread*/ > - while (barrier->in) > + while ((barrier->bar < barrier->count) == wasless) > odp_spin(); > - > - /* Ready */ > - odp_atomic_dec_int(&barrier->out); > - odp_mem_barrier(); > } > + > + odp_mem_barrier(); > }
diff --git a/include/odp_barrier.h b/include/odp_barrier.h index bb4a6c5..0a1404b 100644 --- a/include/odp_barrier.h +++ b/include/odp_barrier.h @@ -28,8 +28,7 @@ extern "C" { */ typedef struct odp_barrier_t { int count; - odp_atomic_int_t in; - odp_atomic_int_t out; + odp_atomic_int_t bar; } odp_barrier_t; diff --git a/platform/linux-generic/source/odp_barrier.c b/platform/linux-generic/source/odp_barrier.c index 64fbdb9..a82b294 100644 --- a/platform/linux-generic/source/odp_barrier.c +++ b/platform/linux-generic/source/odp_barrier.c @@ -11,40 +11,38 @@ void odp_barrier_init_count(odp_barrier_t *barrier, int count) { barrier->count = count; - barrier->in = 0; - barrier->out = count - 1; + barrier->bar = 0; odp_sync_stores(); } +/* + * Efficient barrier_sync - + * + * Barriers are initialized with a count of the number of callers + * that must sync on the barrier before any may proceed. + * + * To avoid race conditions and to permit the barrier to be fully + * reusable, the barrier value cycles between 0..2*count-1. When + * synchronizing the wasless variable simply tracks which half of + * the cycle the barrier was in upon entry. Exit is when the + * barrier crosses to the other half of the cycle. + */ void odp_barrier_sync(odp_barrier_t *barrier) { int count; + int wasless; odp_sync_stores(); + wasless = barrier->bar < barrier->count; + count = odp_atomic_fetch_inc_int(&barrier->bar); - count = odp_atomic_fetch_inc_int(&barrier->in); - - if (count == barrier->count - 1) { - /* If last thread, release others */ - barrier->in = 0; - odp_sync_stores(); - - /* Wait for others to exit */ - while (barrier->out) - odp_spin(); - - /* Ready, reset out counter */ - barrier->out = barrier->count - 1; - odp_sync_stores(); - + if (count == 2*barrier->count-1) { + barrier->bar = 0; } else { - /* Wait for the last thread*/ - while (barrier->in) + while ((barrier->bar < barrier->count) == wasless) odp_spin(); - - /* Ready */ - odp_atomic_dec_int(&barrier->out); - odp_mem_barrier(); } + + odp_mem_barrier(); }
Add odp_mem_barrier() before exit from odp_barrier_sync() Signed-off-by: Bill Fischofer <bill.fischofer@linaro.org> --- include/odp_barrier.h | 3 +- platform/linux-generic/source/odp_barrier.c | 44 ++++++++++++++--------------- 2 files changed, 22 insertions(+), 25 deletions(-)