Is this using the built-in speakers or the headphone jack? Plug in an optical cable and see if the CPU doesn't drop a lot. Or try a USB or Firewire interface.
By default CoreAudio does a lot of processing on audio when using the built-in outputs. It used to mainly be limiting to keep the shitty speakers from blowing, but it has expanded over time. There is obviously a way to tell CoreAudio to cut that out, but how that is done via PortAudio is a question for the PA developers.
The ml_set_interrupts_enabled is the blocking.
On Tue, Nov 9, 2010 at 10:48 AM, Jamie Bullock jamie@postlude.co.uk wrote:
pd doing 'nothing':
10.6% 10.6% mach_kernel ml_set_interrupts_enabled 9.4% 9.4% DspFuncLibiZRedist::DSP::Denoise::processWithLookahead(int, float* const*, int) 6.7% 6.7% DspFuncLib iZRedist::DSP::FftImpl::FftComplex_InPlace(iZRedist::DSP::Cmplx*) const 6.3% 6.3% DspFuncLib DspFuncHelper::process_IIR_xmm_LR(float*, float*, float*, float*, unsigned int) 3.8% 3.8% DspFuncLib iZRedist::Util::Log(float) 2.8% 2.8% AppleHDA NativeInt32ToFloat32_X86 2.5% 2.5% DspFuncLib iZRedist::DSP::FftImpl::FftReal(float const*, iZRedist::DSP::Cmplx*) const 2.3% 2.3% DspFuncLib DspFuncDRC::_dynamicRangeControl(float*, float*, unsigned long, unsigned long) 2.0% 2.0% mach_kernel lo_mach_scall