Re: [PATCH v2 08/14] DMA: edma: Use different eventq for cyclic channels
On 04/11/2014 11:47 AM, Vinod Koul wrote: > On Thu, Apr 10, 2014 at 11:36:30AM -0500, Joel Fernandes wrote: >> On 04/01/2014 08:06 AM, Peter Ujfalusi wrote: >>> To improve latency with cyclic DMA operation it is preferred to >>> use different eventq/tc than the default which is used by all >>> other drivers (mmc, spi, i2c, etc). >>> When preparing the cyclic dma ask for non default queue for the >>> channel which is going to be used with cyclic mode. >>> >>> Signed-off-by: Peter Ujfalusi >>> --- >>> drivers/dma/edma.c | 3 +++ >>> 1 file changed, 3 insertions(+) >>> >>> diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c >>> index 1dd9e8806975..10048b40fac8 100644 >>> --- a/drivers/dma/edma.c >>> +++ b/drivers/dma/edma.c >>> @@ -628,6 +628,9 @@ static struct dma_async_tx_descriptor >>> *edma_prep_dma_cyclic( >>> edesc->pset[i].opt |= TCINTEN; >>> } >>> >>> + /* Use different eventq/tc for cyclic DMA to reduce latency */ >>> + edma_request_non_default_queue(echan->ch_num); >>> + >>> return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags); >>> } >>> >>> >> >> Is there any way to guarantee that the non-default queue is of the >> highest priority, or in other words default queue is of lowest priority. > well as we are discussing in other thread, it would make sense to pass the > required priority (i am using audio so pls give me highest one) > Yes, I'm aware of that part of the discussion ;) I also replied there. This post was sent much earlier on. thanks, -Joel -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v2 08/14] DMA: edma: Use different eventq for cyclic channels
On Thu, Apr 10, 2014 at 11:36:30AM -0500, Joel Fernandes wrote: > On 04/01/2014 08:06 AM, Peter Ujfalusi wrote: > > To improve latency with cyclic DMA operation it is preferred to > > use different eventq/tc than the default which is used by all > > other drivers (mmc, spi, i2c, etc). > > When preparing the cyclic dma ask for non default queue for the > > channel which is going to be used with cyclic mode. > > > > Signed-off-by: Peter Ujfalusi > > --- > > drivers/dma/edma.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c > > index 1dd9e8806975..10048b40fac8 100644 > > --- a/drivers/dma/edma.c > > +++ b/drivers/dma/edma.c > > @@ -628,6 +628,9 @@ static struct dma_async_tx_descriptor > > *edma_prep_dma_cyclic( > > edesc->pset[i].opt |= TCINTEN; > > } > > > > + /* Use different eventq/tc for cyclic DMA to reduce latency */ > > + edma_request_non_default_queue(echan->ch_num); > > + > > return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags); > > } > > > > > > Is there any way to guarantee that the non-default queue is of the > highest priority, or in other words default queue is of lowest priority. well as we are discussing in other thread, it would make sense to pass the required priority (i am using audio so pls give me highest one) -- ~Vinod > I know you set queue 1 as default because by default 0 is higher > priority. And then assigning non-default queue. > > When assigning default to Queue 1, it would be good to also call > assign_priority_to_queue and set QUEPRI to 7 for Queue 1. Since 0, 2 and > 4 are all non-defaults. > > Thanks, > -Joel -- -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v2 08/14] DMA: edma: Use different eventq for cyclic channels
On 04/01/2014 08:06 AM, Peter Ujfalusi wrote: > To improve latency with cyclic DMA operation it is preferred to > use different eventq/tc than the default which is used by all > other drivers (mmc, spi, i2c, etc). > When preparing the cyclic dma ask for non default queue for the > channel which is going to be used with cyclic mode. > > Signed-off-by: Peter Ujfalusi > --- > drivers/dma/edma.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c > index 1dd9e8806975..10048b40fac8 100644 > --- a/drivers/dma/edma.c > +++ b/drivers/dma/edma.c > @@ -628,6 +628,9 @@ static struct dma_async_tx_descriptor > *edma_prep_dma_cyclic( > edesc->pset[i].opt |= TCINTEN; > } > > + /* Use different eventq/tc for cyclic DMA to reduce latency */ > + edma_request_non_default_queue(echan->ch_num); > + > return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags); > } > > Is there any way to guarantee that the non-default queue is of the highest priority, or in other words default queue is of lowest priority. I know you set queue 1 as default because by default 0 is higher priority. And then assigning non-default queue. When assigning default to Queue 1, it would be good to also call assign_priority_to_queue and set QUEPRI to 7 for Queue 1. Since 0, 2 and 4 are all non-defaults. Thanks, -Joel -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH v2 08/14] DMA: edma: Use different eventq for cyclic channels
To improve latency with cyclic DMA operation it is preferred to use different eventq/tc than the default which is used by all other drivers (mmc, spi, i2c, etc). When preparing the cyclic dma ask for non default queue for the channel which is going to be used with cyclic mode. Signed-off-by: Peter Ujfalusi --- drivers/dma/edma.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c index 1dd9e8806975..10048b40fac8 100644 --- a/drivers/dma/edma.c +++ b/drivers/dma/edma.c @@ -628,6 +628,9 @@ static struct dma_async_tx_descriptor *edma_prep_dma_cyclic( edesc->pset[i].opt |= TCINTEN; } + /* Use different eventq/tc for cyclic DMA to reduce latency */ + edma_request_non_default_queue(echan->ch_num); + return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags); } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
