[pulseaudio-discuss] Resampler quality evaluation: now with room noise!

[David Henningsson]

On 2014-09-30 10:41, Alexander E. Patrakov wrote:
> 30.09.2014 14:21, David Henningsson wrote:
>
>> I did a quick test here. I have an old laptop that runs Ubuntu 12.04,
>> with default installed PulseAudio 1.1. Its processor is Intel Pentium M
>> @ 1.4 GHz [1], single core, with an AC'97 codec.
>>
>> Running speaker-test will automatically cause resampling from 48 kHz
>> down to 44.1 kHz, as verified with "pactl list sink-inputs".
>>
>> Under speex-float-1, PulseAudio consumes about 4.3% CPU. With
>> speex-float-3, PA consumes ~8% CPU. With speex-float-5, PA consumes ~13%
>> CPU.
>
> OK. Given that Ubuntu provides the SSE2-optimized library for speex on
> i386,

My CPU seems to include sse2 instructions according to /proc/cpuinfo.

Does speex provide both a sse2 and a non-sse2 implementation, and 
switches dynamically depending on CPU, or is it set at compile time? If 
the latter, i e, if Ubuntu could only ship one implementation by 
default, then probably it would choose the non-sse2 version. I think.

> I think that our results are comparable. Could you please also
> show the actual CPU frequency, if the power-saving features of the
> platform allow the kernel to decrease it?

Uhm. I just checked /sys/devices/system/cpu/cpu0/cpufreq while 
speaker-test was running, and it seemed to alternate frequently between 
600000, 800000, 1000000, and 1200000.

-- 
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic