fsldma: cleanup driver and fix async_tx compatibility
Dudhat Dipen-B09055
B09055 at freescale.com
Tue Feb 2 18:50:05 EST 2010
Hi Ira,
Do these patches accepted to open source kernel??
- Dipen
-----Original Message-----
From: Ira W. Snyder [mailto:iws at ovro.caltech.edu]
Sent: Monday, January 11, 2010 9:59 PM
To: Dudhat Dipen-B09055
Cc: dan.j.williams at intel.com; galak at kernel.crashing.org;
herbert at gondor.apana.org.au; Tabi Timur-B04825; linuxppc-dev at ozlabs.org;
Suresh Vishnu-B05022; Gupta Maneesh-B18878; Li Yang-R58472
Subject: Re: fsldma: cleanup driver and fix async_tx compatibility
On Mon, Jan 11, 2010 at 11:17:04AM +0530, Dudhat Dipen-B09055 wrote:
>
> Hi Ira,
>
> I have tested your patches with async DMA memcpy support. Though I
> haven't captured the improvement figures.
> It works fine for RAID5 memcpy offload as interrupts are coming for
> separate DMA channels while I have ran IOZONE onto RAID partition.
>
Excellent, thanks for running these tests. I'm glad to hear that the
RAID offload is working now.
You shouldn't notice any difference in performance. On a 32MB memcpy
operation, broken into 32x 1MB memcpy(), 1x interrupt(), I noticed less
than 0.1% difference (approx 100,000 ns / 0.1ms). This is probably at or
near the limits of my measurement accuracy.
Ira
> Regards,
> Dipen
>
>
> -----Original Message-----
> From: Dudhat Dipen-B09055
> Sent: Tuesday, January 05, 2010 11:38 AM
> To: 'Ira W. Snyder'; dan.j.williams at intel.com
> Cc: galak at kernel.crashing.org; herbert at gondor.apana.org.au; Tabi
> Timur-B04825; linuxppc-dev at ozlabs.org; Suresh Vishnu-B05022; Gupta
> Maneesh-B18878; Li Yang-R58472
> Subject: RE: fsldma: cleanup driver and fix async_tx compatibility
>
>
> Hi Ira,
>
> I will test it on 85xx hardware and let you know once done.
>
> Thanks
> Dipen
>
>
> -----Original Message-----
> From: Ira W. Snyder [mailto:iws at ovro.caltech.edu]
> Sent: Friday, January 01, 2010 11:41 AM
> To: dan.j.williams at intel.com
> Cc: galak at kernel.crashing.org; herbert at gondor.apana.org.au; Tabi
> Timur-B04825; linuxppc-dev at ozlabs.org; Suresh Vishnu-B05022; Dudhat
> Dipen-B09055; Gupta Maneesh-B18878; Li Yang-R58472
> Subject: fsldma: cleanup driver and fix async_tx compatibility
>
> This patch series cleans up the Freescale DMAEngine driver, including
> verifying the locking and making sure that all code paths are correct.
> There were a few places that seemed suspicious, and they have been
> fixed.
>
> I have written a quick memory->memory DMAEngine test driver, and the
> performance is identical before and after my changes (<0.1% change). I
> measured both setting up the DMA operation (via
> device_prep_dma_interrupt() and device_prep_dma_memcpy()) and the
> actual DMA transfer itself.
>
> As an added bonus, the interrupt load is measurably reduced. My test
> driver transfers 32MB as 32x 1MB chunks + 1 interrupt descriptor,
> using the functions noted above. Previous to this patch series, 31
> interrupts were generated. After this patch series, only a single
> interrupt is generated for the whole transaction.
>
> Some testing on 85xx/86xx hardware would be appreciated. Also, some
> testing by the users attempting to use async_tx and talitos to handle
> RAID offload would be great as well.
>
> Documentation/powerpc/dts-bindings/fsl/dma.txt | 17 +-
> drivers/dma/fsldma.c | 1036
> ++++++++++++------------
> drivers/dma/fsldma.h | 35 +-
> 3 files changed, 556 insertions(+), 532 deletions(-)
>
> Thanks,
> Ira
>
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