RE: [PATCH 4/5] I/OAT: Tighten descriptor setup performance

[Nelson, Shannon]

>-----Original Message-----
>From: Andrew Morton [mailto:akpm@xxxxxxxxxxxxxxxxxxxx] 
>
>On Wed, 17 Oct 2007 17:14:33 -0700
>Shannon Nelson <shannon.nelson@xxxxxxxxx> wrote:
>
>> The change to the async_tx interface cost this driver some 
>performance by
>> spreading the descriptor setup across several functions, 
>including multiple
>> passes over the new descriptor chain.  Here we bring the 
>work back into one
>> primary function and only do one pass.
>> 
>> Signed-off-by: Shannon Nelson <shannon.nelson@xxxxxxxxx>
>> ---
>> 
>>  drivers/dma/ioat_dma.c |  170 
>+++++++++++++++++++++++++-----------------------
>>  drivers/dma/ioatdma.h  |    6 +-
>>  2 files changed, 93 insertions(+), 83 deletions(-)
>> 
>> diff --git a/drivers/dma/ioat_dma.c b/drivers/dma/ioat_dma.c
>> index c44f551..117ac38 100644
>> --- a/drivers/dma/ioat_dma.c
>> +++ b/drivers/dma/ioat_dma.c
>> @@ -46,9 +46,12 @@
>>  /* internal functions */
>>  static void ioat_dma_start_null_desc(struct ioat_dma_chan 
>*ioat_chan);
>>  static void ioat_dma_memcpy_cleanup(struct ioat_dma_chan 
>*ioat_chan);
>> +static inline struct ioat_desc_sw *ioat_dma_get_next_descriptor(
>> +					      struct 
>ioat_dma_chan *ioat_chan);
>
>A forward-declared static inline is pretty weird.  Does gcc 
>actually do the
>right thing with it?

Well, I didn't inspect the opcodes generated...

>
>This function is far too large to be inlined anyway.
>

No prob, I can remove the "inline" and repost.

sln
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