On Tue, Jun 28, 2011 at 09:22:20AM +0300, saeed bishara wrote:
> On Mon, Jun 27, 2011 at 2:02 PM, Russell King - ARM Linux
> wrote:
> > On Mon, Jun 27, 2011 at 01:34:48PM +0300, saeed bishara wrote:
> >> Russell,
> >> I'm curious about the correctness of this patch for systems with
> >> outer ca
On Mon, Jun 27, 2011 at 2:02 PM, Russell King - ARM Linux
wrote:
> On Mon, Jun 27, 2011 at 01:34:48PM +0300, saeed bishara wrote:
>> Russell,
>> I'm curious about the correctness of this patch for systems with
>> outer cache. shouldn't the dsb be issued before the outer cache
>> maintenance?
>
>
lists.linaro.org;
linux-...@vger.kernel.org; linux-arm-ker...@lists.infradead.org; Robert Fekete
Subject: Re: [PATCH v6 00/11] mmc: use nonblock mmc requests to minimize latency
On Mon, Jun 27, 2011 at 12:02 PM, Russell King - ARM Linux
wrote:
> The next thing to think about in DMA-land is wheth
On Mon, Jun 27, 2011 at 12:02 PM, Russell King - ARM Linux
wrote:
> The next thing to think about in DMA-land is whether we should total up
> the size of the SG list and choose whether to flush the individual SG
> elements or do a full cache flush. There becomes a point where the full
> cache fl
On Mon, Jun 27, 2011 at 01:34:48PM +0300, saeed bishara wrote:
> Russell,
> I'm curious about the correctness of this patch for systems with
> outer cache. shouldn't the dsb be issued before the outer cache
> maintenance?
Maybe we should do two passes over SG lists then - one for the inner and
a
>
> +static inline void __dma_sync(void)
> +{
> + dsb();
> +}
> +
> /*
> * Return whether the given device DMA address mask can be supported
> * properly. For example, if your device can only drive the low 24-bits
> @@ -378,6 +383,7 @@ static inline dma_addr_t dma_map_single(struct device
On 27 June 2011 12:02, Russell King - ARM Linux wrote:
> On Mon, Jun 27, 2011 at 11:42:52AM +0200, Per Forlin wrote:
>> Conclusion:
>> Working with mmc the relative cost of DSB is almost none. There seems
>> to be slightly higher number for mmc blocking requests with the DSB
>> patch compared to n
On Mon, Jun 27, 2011 at 11:42:52AM +0200, Per Forlin wrote:
> Conclusion:
> Working with mmc the relative cost of DSB is almost none. There seems
> to be slightly higher number for mmc blocking requests with the DSB
> patch compared to not having it.
These figures suggest that dsb is comparitively
On 24 June 2011 10:58, Per Forlin wrote:
> On 23 June 2011 15:37, Russell King - ARM Linux
> wrote:
>> On Tue, Jun 21, 2011 at 11:26:27AM +0200, Per Forlin wrote:
>>> Here are the results.
>>
>> It looks like this patch is either a no-op or slightly worse. As
>> people have been telling me that
On 23 June 2011 15:37, Russell King - ARM Linux wrote:
> On Tue, Jun 21, 2011 at 11:26:27AM +0200, Per Forlin wrote:
>> Here are the results.
>
> It looks like this patch is either a no-op or slightly worse. As
> people have been telling me that dsb is rather expensive, and this
> patch results i
On Tue, Jun 21, 2011 at 11:26:27AM +0200, Per Forlin wrote:
> Here are the results.
It looks like this patch is either a no-op or slightly worse. As
people have been telling me that dsb is rather expensive, and this
patch results in less dsbs, I'm finding these results hard to believe.
It seems t
On 21 June 2011 10:09, Per Forlin wrote:
> On 21 June 2011 09:53, Russell King - ARM Linux
> wrote:
>> On Sun, Jun 19, 2011 at 11:17:26PM +0200, Per Forlin wrote:
>>> How significant is the cache maintenance over head?
>>
>> Per,
>>
>> Can you measure how much difference this has before and afte
On 21 June 2011 09:53, Russell King - ARM Linux wrote:
> On Sun, Jun 19, 2011 at 11:17:26PM +0200, Per Forlin wrote:
>> How significant is the cache maintenance over head?
>
> Per,
>
> Can you measure how much difference this has before and after your
> patch set please?
Absolutely, I can run the
On Sun, Jun 19, 2011 at 11:17:26PM +0200, Per Forlin wrote:
> How significant is the cache maintenance over head?
Per,
Can you measure how much difference this has before and after your
patch set please? This moves the dsb() out of the individual cache
maintanence functions, such that we will on
How significant is the cache maintenance over head?
It depends, the eMMC are much faster now
compared to a few years ago and cache maintenance cost more due to
multiple cache levels and speculative cache pre-fetch. In relation the
cost for handling the caches have increased and is now a bottle neck
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