On Thu, Mar 12, 2015 at 5:01 PM, David Medine dmedine@ucsd.edu wrote:
@Charles: None of those five sentences is a misconception. When I said 'DSP functions' I meant the functions of the form 'whatever_tilde_perform', not the dsp tick function. I see how this might lead to a misunderstanding.
Sorry if I was unclear as well. We *are* trying to split hairs here, of course, just to have an accurate description.
It's not *all* of the dsp functions. I thought this was unclear and tried to clarify: rather than scheduling them more often, it actually just loops over the sub-graphs multiple times when the block size is low. There is always a parent function which is being run once every 64 samples (the default).
Also, I see that suseconds_t (which is the type of now.tv_usec) is an integer, as I had previously thought, so I am really perplexed as to how [delay] can apparently deliver bangs within less than 1us. I would love for someone to explain this to me. It is a small detail and it doesn't really matter in practice, but I am annoyed when my inferences are not correct -- especially when I send them to the Pd list!
On 3/12/2015 1:58 PM, Charles Z Henry wrote:
On Thu, Mar 12, 2015 at 3:18 PM, David Medine dmedine@ucsd.edu wrote:
Yeah, of course. Block size 1 and high sampling rate will make the timing between control and audio super tight (ChucK does this, for example). It will also eat the hell out of your CPU. It's a trade off. This is because you start calling all the DSP functions once every 1/192k seconds instead of once every 1.45ms.
This last sentence is also a misconception--the dsp tick function is called every 64 samples, as commonly defined.
sys_time_per_dsp_tick = (TIMEUNITPERSECOND) * ((double)sys_schedblocksize) / sys_dacsr;sys_schedblocksize gets set from DEFDACBLKSIZE
So, the dsp_tick gets called, and when there is a sub-patch with [block~ 1], it loops over the graph generated from the sub-patch 64 times.
You'd find this behavior coded with the block prologue and epilogue functions.