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Groups > linux.kernel > #1242099 > unrolled thread
| Started by | Rameshwar Prasad Sahu <rsahu@apm.com> |
|---|---|
| First post | 2015-10-08 11:10 +0200 |
| Last post | 2015-10-14 12:30 +0200 |
| Articles | 5 — 3 participants |
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[PATCH v2] dmaengine: xgene-dma: Disable memcpy operation due to performance drop Rameshwar Prasad Sahu <rsahu@apm.com> - 2015-10-08 11:10 +0200
Re: [PATCH v2] dmaengine: xgene-dma: Disable memcpy operation due to performance drop Vinod Koul <vinod.koul@intel.com> - 2015-10-09 18:20 +0200
Re: [PATCH v2] dmaengine: xgene-dma: Disable memcpy operation due to performance drop Rameshwar Sahu <rsahu@apm.com> - 2015-10-09 18:40 +0200
Re: [PATCH v2] dmaengine: xgene-dma: Disable memcpy operation due to performance drop Vinod Koul <vinod.koul@intel.com> - 2015-10-12 16:30 +0200
Re: [PATCH v2] dmaengine: xgene-dma: Disable memcpy operation due to performance drop Rameshwar Sahu <rsahu@apm.com> - 2015-10-14 12:30 +0200
| From | Rameshwar Prasad Sahu <rsahu@apm.com> |
|---|---|
| Date | 2015-10-08 11:10 +0200 |
| Subject | [PATCH v2] dmaengine: xgene-dma: Disable memcpy operation due to performance drop |
| Message-ID | <qhfn3-7oy-11@gated-at.bofh.it> |
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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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| From | Vinod Koul <vinod.koul@intel.com> |
|---|---|
| Date | 2015-10-09 18:20 +0200 |
| Subject | Re: [PATCH v2] dmaengine: xgene-dma: Disable memcpy operation due to performance drop |
| Message-ID | <qhIyK-7ea-19@gated-at.bofh.it> |
| In reply to | #1242099 |
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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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| From | Rameshwar Sahu <rsahu@apm.com> |
|---|---|
| Date | 2015-10-09 18:40 +0200 |
| Subject | Re: [PATCH v2] dmaengine: xgene-dma: Disable memcpy operation due to performance drop |
| Message-ID | <qhIS5-7BS-1@gated-at.bofh.it> |
| In reply to | #1243511 |
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
--
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| From | Vinod Koul <vinod.koul@intel.com> |
|---|---|
| Date | 2015-10-12 16:30 +0200 |
| Subject | Re: [PATCH v2] dmaengine: xgene-dma: Disable memcpy operation due to performance drop |
| Message-ID | <qiMgW-1zC-15@gated-at.bofh.it> |
| In reply to | #1243517 |
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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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| From | Rameshwar Sahu <rsahu@apm.com> |
|---|---|
| Date | 2015-10-14 12:30 +0200 |
| Subject | Re: [PATCH v2] dmaengine: xgene-dma: Disable memcpy operation due to performance drop |
| Message-ID | <qjrtM-40U-11@gated-at.bofh.it> |
| In reply to | #1244742 |
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 linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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