Re: [Discuss-gnuradio] why alignment feature work only when output_multiple not set

[Tom Rondeau]

On Thu, Jun 18, 2015 at 8:29 AM, Tiankun Hu <address@hidden> wrote:

Hi Tom,
Thanks your reply, I have another question, in function "min_available_space" why buffer_size/2 is best ? 

I'm not really sure. That's a question for Eric.

What happens when you change it? How does it affect performance?

Tom

 

在 2015年06月16日 21:31, Tom Rondeau 写道:

On Tue, Jun 16, 2015 at 8:57 AM, Tiankun Hu <address@hidden> wrote:

Hi,
After go through the block_executor.cc, I found alignment feature work only when output_multiple not set, why them can not work at the same time?

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Thanks
Tiankun

Because they are competing objectives. The alignment tries to keep buffers aligned and therefore the number of items will be based on a multiple of the alignment requirement. If you need an output multiple that's different than that, which one should the scheduler choose?

Note that the buffers always begin on a page and so are inherently aligned. If your output multiple is also a multiple of the alignment for the data type, then you'll always be aligned.

Tom

-- 
Thanks
Tiankun