[alsa-devel] PulseAudio and SNDRV_PCM_INFO_BATCH

[Alexander E. Patrakov]

sorry, I need to clarify some of my words

12.06.2015 18:43, Alexander E. Patrakov wrote:
> To guarantee the reproducibility of this experiment, the entire system
> (Gentoo stage3 plus PulseAudio plus laptop-mode-tools) has been put in
> the initramfs,

Clarification due to a possible "why PulseAudio" question. I have 
actually reused an old initramfs that I put together in order to measure 
the effect of various resamplers on battery life. Result back then: with 
1s latency, when resampling from 44.1 to 48 kHz, speex-float-5 robs 734 
seconds of battery life, out of 26731, as compared to speex-float-1. 
I.e. less than the battery lost due to 6 months of aging.

The scripts are attached, measure.sh is called from a script in 
/etc/local.d.

> 2. Limiting of the sleep time in the timer-based scheduling logic to a
> similar value. If this ends up below 30 ms, then we can simplify
> PulseAudio by removing all traces of the rewind logic.

I should point out that CRAS (another sound server that implements 
timer-based scheduling, from ChromeOS) has no rewind logic at all, and 
relies on clients not to request insanely large buffer size. Also, it 
contains no batch-card logic.

-- 
Alexander E. Patrakov
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