* [PATCH v2] dmaengine: xgene-dma: Disable memcpy operation due to performance drop @ 2015-10-08 9:06 Rameshwar Prasad Sahu 2015-10-09 16:12 ` Vinod Koul 0 siblings, 1 reply; 5+ messages in thread From: Rameshwar Prasad Sahu @ 2015-10-08 9:06 UTC (permalink / raw) To: linux-arm-kernel The DMA engine supports memory copy, RAID5 XOR, RAID6 PQ, and other computations. But the bandwidth of the entire DMA engine is shared among all channels. This patch re-configures operations availability such that one can achieve maximum performance for XOR and PQ computation by removing the memory offload operations. Signed-off-by: Rameshwar Prasad Sahu <rsahu@apm.com> --- drivers/dma/xgene-dma.c | 1 - 1 file changed, 1 deletion(-) diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c index 8d57b1b..cd38022 100644 --- a/drivers/dma/xgene-dma.c +++ b/drivers/dma/xgene-dma.c @@ -1707,7 +1707,6 @@ static void xgene_dma_set_caps(struct xgene_dma_chan *chan, dma_cap_zero(dma_dev->cap_mask); /* Set DMA device capability */ - dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask); dma_cap_set(DMA_SG, dma_dev->cap_mask); /* Basically here, the X-Gene SoC DMA engine channel 0 supports XOR -- 1.8.2.1 ^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH v2] dmaengine: xgene-dma: Disable memcpy operation due to performance drop 2015-10-08 9:06 [PATCH v2] dmaengine: xgene-dma: Disable memcpy operation due to performance drop Rameshwar Prasad Sahu @ 2015-10-09 16:12 ` Vinod Koul 2015-10-09 16:38 ` Rameshwar Sahu 0 siblings, 1 reply; 5+ messages in thread From: Vinod Koul @ 2015-10-09 16:12 UTC (permalink / raw) To: linux-arm-kernel On Thu, Oct 08, 2015 at 02:36:57PM +0530, Rameshwar Prasad Sahu wrote: > The DMA engine supports memory copy, RAID5 XOR, RAID6 PQ, and other > computations. But the bandwidth of the entire DMA engine is shared > among all channels. This patch re-configures operations availability > such that one can achieve maximum performance for XOR and PQ > computation by removing the memory offload operations. > > Signed-off-by: Rameshwar Prasad Sahu <rsahu@apm.com> > --- > drivers/dma/xgene-dma.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c > index 8d57b1b..cd38022 100644 > --- a/drivers/dma/xgene-dma.c > +++ b/drivers/dma/xgene-dma.c > @@ -1707,7 +1707,6 @@ static void xgene_dma_set_caps(struct xgene_dma_chan *chan, > dma_cap_zero(dma_dev->cap_mask); > > /* Set DMA device capability */ > - dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask); > dma_cap_set(DMA_SG, dma_dev->cap_mask); This will not work. Still clients can invoke memcpy operation. You need to remove the callback -- ~Vinod ^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v2] dmaengine: xgene-dma: Disable memcpy operation due to performance drop 2015-10-09 16:12 ` Vinod Koul @ 2015-10-09 16:38 ` Rameshwar Sahu 2015-10-12 14:23 ` Vinod Koul 0 siblings, 1 reply; 5+ messages in thread From: Rameshwar Sahu @ 2015-10-09 16:38 UTC (permalink / raw) To: linux-arm-kernel Hi Vinod, On Fri, Oct 9, 2015 at 9:42 PM, Vinod Koul <vinod.koul@intel.com> wrote: > On Thu, Oct 08, 2015 at 02:36:57PM +0530, Rameshwar Prasad Sahu wrote: >> The DMA engine supports memory copy, RAID5 XOR, RAID6 PQ, and other >> computations. But the bandwidth of the entire DMA engine is shared >> among all channels. This patch re-configures operations availability >> such that one can achieve maximum performance for XOR and PQ >> computation by removing the memory offload operations. >> >> Signed-off-by: Rameshwar Prasad Sahu <rsahu@apm.com> >> --- >> drivers/dma/xgene-dma.c | 1 - >> 1 file changed, 1 deletion(-) >> >> diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c >> index 8d57b1b..cd38022 100644 >> --- a/drivers/dma/xgene-dma.c >> +++ b/drivers/dma/xgene-dma.c >> @@ -1707,7 +1707,6 @@ static void xgene_dma_set_caps(struct xgene_dma_chan *chan, >> dma_cap_zero(dma_dev->cap_mask); >> >> /* Set DMA device capability */ >> - dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask); >> dma_cap_set(DMA_SG, dma_dev->cap_mask); > > This will not work. Still clients can invoke memcpy operation. You need to > remove the callback Got it, instead of removing the callback registration can we keep it inside the condition like.. if (dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask)) dma_dev->device_prep_dma_memcpy = xgene_dma_prep_memcpy; > > -- > ~Vinod ^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v2] dmaengine: xgene-dma: Disable memcpy operation due to performance drop 2015-10-09 16:38 ` Rameshwar Sahu @ 2015-10-12 14:23 ` Vinod Koul 2015-10-14 10:20 ` Rameshwar Sahu 0 siblings, 1 reply; 5+ messages in thread From: Vinod Koul @ 2015-10-12 14:23 UTC (permalink / raw) To: linux-arm-kernel On Fri, Oct 09, 2015 at 10:08:32PM +0530, Rameshwar Sahu wrote: > Hi Vinod, > > On Fri, Oct 9, 2015 at 9:42 PM, Vinod Koul <vinod.koul@intel.com> wrote: > > On Thu, Oct 08, 2015 at 02:36:57PM +0530, Rameshwar Prasad Sahu wrote: > >> The DMA engine supports memory copy, RAID5 XOR, RAID6 PQ, and other > >> computations. But the bandwidth of the entire DMA engine is shared > >> among all channels. This patch re-configures operations availability > >> such that one can achieve maximum performance for XOR and PQ > >> computation by removing the memory offload operations. > >> > >> Signed-off-by: Rameshwar Prasad Sahu <rsahu@apm.com> > >> --- > >> drivers/dma/xgene-dma.c | 1 - > >> 1 file changed, 1 deletion(-) > >> > >> diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c > >> index 8d57b1b..cd38022 100644 > >> --- a/drivers/dma/xgene-dma.c > >> +++ b/drivers/dma/xgene-dma.c > >> @@ -1707,7 +1707,6 @@ static void xgene_dma_set_caps(struct xgene_dma_chan *chan, > >> dma_cap_zero(dma_dev->cap_mask); > >> > >> /* Set DMA device capability */ > >> - dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask); > >> dma_cap_set(DMA_SG, dma_dev->cap_mask); > > > > This will not work. Still clients can invoke memcpy operation. You need to > > remove the callback > > Got it, instead of removing the callback registration can we keep it > inside the condition like.. > > if (dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask)) > dma_dev->device_prep_dma_memcpy = xgene_dma_prep_memcpy; But the code is dead and will not be tested and hence not maintained. I do not see a reason to keep dead code in kernel -- ~Vinod ^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v2] dmaengine: xgene-dma: Disable memcpy operation due to performance drop 2015-10-12 14:23 ` Vinod Koul @ 2015-10-14 10:20 ` Rameshwar Sahu 0 siblings, 0 replies; 5+ messages in thread From: Rameshwar Sahu @ 2015-10-14 10:20 UTC (permalink / raw) To: linux-arm-kernel Hi Vinod, On Mon, Oct 12, 2015 at 7:53 PM, Vinod Koul <vinod.koul@intel.com> wrote: > On Fri, Oct 09, 2015 at 10:08:32PM +0530, Rameshwar Sahu wrote: >> Hi Vinod, >> >> On Fri, Oct 9, 2015 at 9:42 PM, Vinod Koul <vinod.koul@intel.com> wrote: >> > On Thu, Oct 08, 2015 at 02:36:57PM +0530, Rameshwar Prasad Sahu wrote: >> >> The DMA engine supports memory copy, RAID5 XOR, RAID6 PQ, and other >> >> computations. But the bandwidth of the entire DMA engine is shared >> >> among all channels. This patch re-configures operations availability >> >> such that one can achieve maximum performance for XOR and PQ >> >> computation by removing the memory offload operations. >> >> >> >> Signed-off-by: Rameshwar Prasad Sahu <rsahu@apm.com> >> >> --- >> >> drivers/dma/xgene-dma.c | 1 - >> >> 1 file changed, 1 deletion(-) >> >> >> >> diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c >> >> index 8d57b1b..cd38022 100644 >> >> --- a/drivers/dma/xgene-dma.c >> >> +++ b/drivers/dma/xgene-dma.c >> >> @@ -1707,7 +1707,6 @@ static void xgene_dma_set_caps(struct xgene_dma_chan *chan, >> >> dma_cap_zero(dma_dev->cap_mask); >> >> >> >> /* Set DMA device capability */ >> >> - dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask); >> >> dma_cap_set(DMA_SG, dma_dev->cap_mask); >> > >> > This will not work. Still clients can invoke memcpy operation. You need to >> > remove the callback >> >> Got it, instead of removing the callback registration can we keep it >> inside the condition like.. >> >> if (dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask)) >> dma_dev->device_prep_dma_memcpy = xgene_dma_prep_memcpy; > > But the code is dead and will not be tested and hence not maintained. I do > not see a reason to keep dead code in kernel Got it, I will remove the memcpy offload support and will send another patch for review. > > -- > ~Vinod ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2015-10-14 10:20 UTC | newest] Thread overview: 5+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2015-10-08 9:06 [PATCH v2] dmaengine: xgene-dma: Disable memcpy operation due to performance drop Rameshwar Prasad Sahu 2015-10-09 16:12 ` Vinod Koul 2015-10-09 16:38 ` Rameshwar Sahu 2015-10-12 14:23 ` Vinod Koul 2015-10-14 10:20 ` Rameshwar Sahu
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).