Re: [Discuss-gnuradio] A simple flow-graph that is giving me infinite grief

2011-07-04 Thread Michael Dickens
One should be able to pretty easily do a single buffer (map or not), or double map buffer. Either way, one needs to check for wrap. The former (single buffer), as Josh states, requires a memory copy every so often (when wrap happens). There is a trade-off between buffer allocation size and ho

Re: [Discuss-gnuradio] A simple flow-graph that is giving me infinite grief

2011-07-03 Thread Marcus D. Leech
Suppose that we didn't have a specially mapped memory. I believe the scheduler could easily ensure that contiguous chunks of memory are always passed into the work function with little overhead for both read and for write. Now, I bet there will be a slight problem when you have a block with "hist

Re: [Discuss-gnuradio] A simple flow-graph that is giving me infinite grief

2011-07-03 Thread Josh Blum
>> >> I wonder if that assertion is generally true, or only in some cases? >> Increment and test shouldn't be *that* expensive. >> > > I'm sure the benefit varies depending on the situation, including some where > there is no benefit. But modulo increments add a conditional operation for > every

Re: [Discuss-gnuradio] A simple flow-graph that is giving me infinite grief

2011-06-29 Thread Johnathan Corgan
On Wed, Jun 29, 2011 at 09:24, Marcus D. Leech wrote: > ** > On 29/06/2011 12:12 PM, Johnathan Corgan wrote: > > GNU Radio achieves its streaming performance in part due to a circular > buffer design that maps the same physical memory twice in the virtual memory > map for the process, directly ad

Re: [Discuss-gnuradio] A simple flow-graph that is giving me infinite grief

2011-06-29 Thread Johnathan Corgan
On Tue, Jun 28, 2011 at 21:38, Marcus D. Leech wrote: > I'll make the observation that there's just got to be a better buffer > allocation policy than the existing one. Should it *really* take > Gigabytes of VM, and hundreds of MB of RSS to execute the flow-graph I've > attached? The largest

Re: [Discuss-gnuradio] A simple flow-graph that is giving me infinite grief

2011-06-29 Thread Marcus D. Leech
On 29/06/2011 12:12 PM, Johnathan Corgan wrote: On Tue, Jun 28, 2011 at 21:38, Marcus D. Leech > wrote: I'll make the observation that there's just got to be a better buffer allocation policy than the existing one. Should it *really* take Gigabytes of