Playback stutters

Hey,

audio playback stutters on my system. All playback programms I have tested have this problem (with and without artsd). I use alsa driver 0.9.0beta12. The soundcard is a no-name ALS4000 soundcard. My system: Linux 2.4.18, Debian testing, Dual Athlon, Tyan S2460. I have read that often IRQ problems cause those kind of problems, but I already tried to disable as much as possible hardware to free up interrups. I also changed the order of the PCI cards and I tried it with and without MP Interrupts. The playback stutters if e.g. I drag around windows or a programm starts (even if the load is very low). It doesn't stutter if I do heavy calcualtion (like running kfract multiple times) and the load is above 4. What else should I try to narrow down the problem?

regards,
Roland Schulz

I am getting the same with stock 2.4.18, DELL Inspiron laptop (Maestro 3i), my test is:

I am getting the same with stock 2.4.18, DELL Inspiron laptop (Maestro 3i), my test is:

copy a cd image file from one partition to another, while trying to play an mp3 using mpg123.

The mp3 skips all over the place.

Quoted 6 lines

I am getting the same with stock 2.4.18, DELL Inspiron laptop (Maestro 3i), my test is:

copy a cd image file from one partition to another, while trying to play an mp3 using mpg123.

Quoted 1 line

The mp3 skips all over the place.

since you almost certainly have IDE drivers, have you configured them correctly using hdparm? these are source of considerable scheduling latency, in ways that AFAIK are not improved by any of the "latency reducing" patches available. don't ask me how to configure them - i only use SCSI drives - but a quick google search should reveal relevant advice.

Quoted 6 lines · Paul Davis

Quoted 6 lines

I am getting the same with stock 2.4.18, DELL Inspiron laptop (Maestro 3i), my test is:

copy a cd image file from one partition to another, while trying to play an mp3 using mpg123.

Quoted 8 lines

Quoted 1 line

The mp3 skips all over the place.

since you almost certainly have IDE drivers, have you configured them correctly using hdparm? these are source of considerable scheduling latency, in ways that AFAIK are not improved by any of the "latency reducing" patches available. don't ask me how to configure them - i only use SCSI drives - but a quick google search should reveal relevant advice.

thanks

hdparm improves the situation, but I still get some (minimal) skips now:

zen8100a:~# hdparm /dev/hda

/dev/hda:

 multcount    = 16 (on)
 I/O support  =  1 (32-bit)
 unmaskirq    =  1 (on)
 using_dma    =  1 (on)
 keepsettings =  0 (off)
 nowerr       =  0 (off)
 readonly     =  0 (off)
 readahead    =  8 (on)

geometry = 7296/255/63, sectors = 117210240, start = 0
busstate = 1 (on)

My current 'test':
- playing an mp3
- running make clean && make bzImage
- copying a cd image between two partitions
- loading up the odd application (eg. mozilla)

With hdparm settings I've tried:
- 2.4.18 + preempt + lockbreak
- 2.4.18 + lowlatency
- 2.4.19-pre3-ac3 + preempt

These seem to all give the same minimal skips with above activities.

No skips with only the kernel compile (not doing the large copy).

CORRECTION:
Just retested with full hdparm (added -u setting) settings on 2.4.19-pre3-ac+preempt, and no skipping with above activities. This seems pretty good.

I could generate skips when switching from X to text console. Could not generate skip when cycling virtual desktops within X (at high key repeat rate). Again this seems pretty good.

-----Original Message-----
From: [email protected] [mailto:[email protected]]On Behalf Of Zenaan Harkness
Sent: 20 March 2002 05:49
To: Paul Davis
Cc: [email protected]; [email protected]
Subject: Re: [Alsa-devel] Re: Playback stutters - Correction

Quoted 2 lines · Zenaan Harkness

Quoted 1 line · Paul Davis

Quoted 1 line

I am getting the same with stock 2.4.18, DELL Inspiron

laptop (Maestro

Quoted 3 lines

Quoted 3 lines

Quoted 3 lines

3i), my test is:

copy a cd image file from one partition to another, while

trying to play

Quoted 36 lines

Quoted 10 lines

Quoted 3 lines

an mp3 using mpg123.

The mp3 skips all over the place.

since you almost certainly have IDE drivers, have you configured them correctly using hdparm? these are source of considerable scheduling latency, in ways that AFAIK are not improved by any of the "latency reducing" patches available. don't ask me how to configure them - i only use SCSI drives - but a quick google search should reveal relevant advice.

thanks

hdparm improves the situation, but I still get some (minimal) skips now:

zen8100a:~# hdparm /dev/hda

/dev/hda:

 multcount    = 16 (on)
 I/O support  =  1 (32-bit)
 unmaskirq    =  1 (on)
 using_dma    =  1 (on)
 keepsettings =  0 (off)
 nowerr       =  0 (off)
 readonly     =  0 (off)
 readahead    =  8 (on)

geometry = 7296/255/63, sectors = 117210240, start = 0
busstate = 1 (on)

My current 'test':
- playing an mp3
- running make clean && make bzImage
- copying a cd image between two partitions
- loading up the odd application (eg. mozilla)

Quoted 8 lines

With hdparm settings I've tried:
- 2.4.18 + preempt + lockbreak
- 2.4.18 + lowlatency
- 2.4.19-pre3-ac3 + preempt

These seem to all give the same minimal skips with above activities.

No skips with only the kernel compile (not doing the large copy).

CORRECTION:
Just retested with full hdparm (added -u setting) settings on 2.4.19-pre3-ac+preempt, and no skipping with above activities. This seems pretty good.

I could generate skips when switching from X to text console. Could not generate skip when cycling virtual desktops within X (at high key repeat rate). Again this seems pretty good.

thanks
zen

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Just for your info, the Windows sound drivers for the Dell are just as bad. I propose that it is a hardware problem, and not an alsa problem.

Quoted 8 lines

CORRECTION:
Just retested with full hdparm (added -u setting) settings on 2.4.19-pre3-ac+preempt, and no skipping with above activities. This seems pretty good.

I could generate skips when switching from X to text console. Could not generate skip when cycling virtual desktops within X (at high key repeat rate). Again this seems pretty good.

this is a know deficiency in the vt "driver", and is noted in Andrew Morton's "Things Not To Do" while requiring low scheduling latency. it would be nice if the vt code was fixed sometime, but right now, i think it can cause a scheduling delay for up to about 50ms.

btw, i think it is still the case the Andrew's patch provides more reliable and lower absolute latency than the preemption patch.

Quoted 8 lines

CORRECTION:
Just retested with full hdparm (added -u setting) settings on 2.4.19-pre3-ac+preempt, and no skipping with above activities. This seems pretty good.

I could generate skips when switching from X to text console. Could not generate skip when cycling virtual desktops within X (at high key repeat rate). Again this seems pretty good.

this is a know deficiency in the vt "driver", and is noted in Andrew Morton's "Things Not To Do" while requiring low scheduling latency. it would be nice if the vt code was fixed sometime, but right now, i think it can cause a scheduling delay for up to about 50ms.

btw, i think it is still the case the Andrew's patch provides more reliable and lower absolute latency than the preemption patch.