From: Yan Wang <yan.wang@linux.intel.com> The purpose of checking half fullness is sending trace data as soon as possible. It will avoid local DMA trace buffer full and unsent trace data overwritten. If DMA trace copying is running currently, it is unnecessary to checking half fullness local DMA trace buffer. The following is implementation details: 1. Add one flag in DMA trace data strcuture. 2. Set/unset this flag in trace_work() callback. 3. Add checking for this flag in dtrace_event(). Signed-off-by: Yan Wang <yan.wang@linux.intel.com> --- src/include/reef/dma-trace.h | 1 + src/lib/dma-trace.c | 17 +++++++++++++++++ 2 files changed, 18 insertions(+) diff --git a/src/include/reef/dma-trace.h b/src/include/reef/dma-trace.h index 641a4dc..21824f3 100644 --- a/src/include/reef/dma-trace.h +++ b/src/include/reef/dma-trace.h @@ -60,6 +60,7 @@ struct dma_trace_data { uint32_t host_size; struct work dmat_work; uint32_t enabled; + uint32_t copy_in_progress; spinlock_t lock; }; diff --git a/src/lib/dma-trace.c b/src/lib/dma-trace.c index 763e955..9dfe7c7 100644 --- a/src/lib/dma-trace.c +++ b/src/lib/dma-trace.c @@ -56,6 +56,9 @@ static uint64_t trace_work(void *data, uint64_t delay) if (avail == 0) return DMA_TRACE_US; + /* DMA trace copying is working */ + d->copy_in_progress = 1; + /* make sure we dont write more than buffer */ if (avail > DMA_TRACE_LOCAL_SIZE) avail = DMA_TRACE_LOCAL_SIZE; @@ -100,7 +103,12 @@ static uint64_t trace_work(void *data, uint64_t delay) out: spin_lock_irq(&d->lock, flags); + buffer->avail -= size; + + /* DMA trace copying is done */ + d->copy_in_progress = 0; + spin_unlock_irq(&d->lock, flags); /* reschedule the trace copying work */ @@ -138,6 +146,7 @@ int dma_trace_init(struct dma_trace_data *d) buffer->avail = 0; d->host_offset = 0; d->enabled = 0; + d->copy_in_progress = 0; list_init(&d->config.elem_list); work_init(&d->dmat_work, trace_work, d, WORK_ASYNC); @@ -226,6 +235,14 @@ void dtrace_event(const char *e, uint32_t length) spin_lock_irq(&trace_data->lock, flags); dtrace_add_event(e, length); + + /* if DMA trace copying is working */ + /* don't check if local buffer is half full */ + if (trace_data->copy_in_progress) { + spin_unlock_irq(&trace_data->lock, flags); + return; + } + spin_unlock_irq(&trace_data->lock, flags); /* schedule copy now if buffer > 50% full */ -- 2.7.4