| Message ID | 1444295217-3099-1-git-send-email-rsahu@apm.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
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
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 -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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
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 -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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
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(-) -- 1.8.2.1 -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html