Re: [fluid-dev] ALSA driver consuming too much CPU

[Mihail Zenkov]

On Tue, 21 Nov 2006 16:14:25 +0000
Paul Millar <address@hidden> wrote:

> Hi Mihail,
> 
> On Tuesday 21 November 2006 15:16, Mihail Zenkov wrote:
> > > I can set the sample rate to 48kHz in fluid_settings_t.  But, when I
> > > start the audio output, it falls back to 41.1kHz.  Setting the ALSA
> > > device to "default" still gives 100% CPU usage, but "hw:0" works fine.
> >
> > Please, do 'cat /proc/asound/cards' and
> > 'cat /proc/asound/card0/pcm0p/sub0/hw_params' when you have problem
> > (100% cpu) and repeat this when don't have.
> 
> I've included results for all four possible combinations ("hw:0" vs 
> "default", 
> 44.1kHz vs 48kHz) below.
> 
> Cheers,
> 
> Paul.
> 
> 
> ALSA "hw:0" device
> ==================
> 
> 44.1kHz sample rate (no problems)
> -------------------
>  0 [AudioPCI       ]: ENS1371 - Ensoniq AudioPCI
>                       Ensoniq AudioPCI ENS1371 at 0xb400, irq 217
>  1 [I82801DBICH4   ]: ICH4 - Intel 82801DB-ICH4
>                       Intel 82801DB-ICH4 with ALC650D at 0xeb000000, irq 209
> access: RW_INTERLEAVED
> format: S16_LE
> subformat: STD
> channels: 2
> rate: 44100 (1445100000/32768)
> period_size: 65
> buffer_size: 1040
> tick_time: 4000
> 
> 48kHz sample rate ("The sample rate is set to 44100, the synth...")
> -----------------
>  0 [AudioPCI       ]: ENS1371 - Ensoniq AudioPCI
>                       Ensoniq AudioPCI ENS1371 at 0xb400, irq 217
>  1 [I82801DBICH4   ]: ICH4 - Intel 82801DB-ICH4
>                       Intel 82801DB-ICH4 with ALC650D at 0xeb000000, irq 209
> access: RW_INTERLEAVED
> format: S16_LE
> subformat: STD
> channels: 2
> rate: 44100 (1445100000/32768)
> period_size: 65
> buffer_size: 1040
> tick_time: 4000
> 
> 
> 
> ALSA "default" device
> =====================
> 
> 44.1kHz sample rate (100% CPU)
> -------------------
>  0 [AudioPCI       ]: ENS1371 - Ensoniq AudioPCI
>                       Ensoniq AudioPCI ENS1371 at 0xb400, irq 217
>  1 [I82801DBICH4   ]: ICH4 - Intel 82801DB-ICH4
>                       Intel 82801DB-ICH4 with ALC650D at 0xeb000000, irq 209
> access: MMAP_INTERLEAVED
> format: S16_LE
> subformat: STD
> channels: 2
> rate: 48000 (1572864000/32768)
> period_size: 1024
> buffer_size: 16384
> tick_time: 4000
> 
> 
> 48kHz sample rate (100% CPU)
> -----------------
>  0 [AudioPCI       ]: ENS1371 - Ensoniq AudioPCI
>                       Ensoniq AudioPCI ENS1371 at 0xb400, irq 217
>  1 [I82801DBICH4   ]: ICH4 - Intel 82801DB-ICH4
>                       Intel 82801DB-ICH4 with ALC650D at 0xeb000000, irq 209
> access: MMAP_INTERLEAVED
> format: S16_LE
> subformat: STD
> channels: 2
> rate: 48000 (1572864000/32768)
> period_size: 1024
> buffer_size: 16384
> tick_time: 4000
> 

IMHO problem in alsa driver for es1371. When you use hw:0, alsa work
with SR=44,1kHz and use RW_INTERLEAVED mode. But when you try use
default device it do resampling to 48kHz. Resmling in from alsa-lib
work in MMAP_INTERLEAVED mode but you system (driver?) dislike this
mode.
IMHO alsa driver for es1317 have problem with change sampling rate and
with mmap. Try ask in alsa mail list or send bug report.