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Groups > linux.kernel > #1242094
| From | Rameshwar Sahu <rsahu@apm.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH] dmaengine: xgene-dma: Disable memcpy operation due to performance drop |
| Date | 2015-10-08 11:00 +0200 |
| Message-ID | <qhfdp-6Y3-21@gated-at.bofh.it> (permalink) |
| References | <qheKm-6pG-21@gated-at.bofh.it> <qhfdp-6Y3-13@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Thu, Oct 8, 2015 at 2:23 PM, Arnd Bergmann <arnd@arndb.de> wrote: > On Thursday 08 October 2015 13:55:16 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 | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c >> index 8d57b1b..2998fcb 100644 >> --- a/drivers/dma/xgene-dma.c >> +++ b/drivers/dma/xgene-dma.c >> @@ -154,6 +154,7 @@ >> #define XGENE_DMA_MAX_XOR_SRC 5 >> #define XGENE_DMA_16K_BUFFER_LEN_CODE 0x0 >> #define XGENE_DMA_INVALID_LEN_CODE 0x7800000000000000ULL >> +#undef XGENE_DMA_MEMCPY_ENABLE >> >> /* X-Gene DMA descriptor error codes */ >> #define ERR_DESC_AXI 0x01 >> @@ -1707,7 +1708,9 @@ static void xgene_dma_set_caps(struct xgene_dma_chan *chan, >> dma_cap_zero(dma_dev->cap_mask); >> >> /* Set DMA device capability */ >> +#ifdef XGENE_DMA_MEMCPY_ENABLE >> dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask); >> +#endif >> dma_cap_set(DMA_SG, dma_dev->cap_mask); >> >> /* Basically here, the X-Gene SoC DMA engine channel 0 supports XOR > > I don't see what the #ifdef gains you here when the setting is > hardcoded. Why not just remove that DMA_MEMCPY capability completely > if you don't want to use it? Okay Arnd, > > Arnd > -- > 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 -- 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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[PATCH] dmaengine: xgene-dma: Disable memcpy operation due to performance drop Rameshwar Prasad Sahu <rsahu@apm.com> - 2015-10-08 10:30 +0200
Re: [PATCH] dmaengine: xgene-dma: Disable memcpy operation due to performance drop Arnd Bergmann <arnd@arndb.de> - 2015-10-08 11:00 +0200
Re: [PATCH] dmaengine: xgene-dma: Disable memcpy operation due to performance drop Rameshwar Sahu <rsahu@apm.com> - 2015-10-08 11:00 +0200
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