On Friday 19 January 2007 03:53, [EMAIL PROTECTED] wrote:
> [Should this and my previous message have gone to ivtv-devel
> instead?]
>
> [ivtv 0.4.0, myth 0.18.1, 5xPVR-250's and ivtv 0.4.1, myth 0.18.1,
> 1xPVR-350.]
>
> When ivtv data isn't being read fast enough because of a short-term
> spike in disk I/O due to a big MySQL query (see my previous message
> today), I get a ton of these messages emitted in my syslog:
>
> Jan 17 21:00:19 myth-master-backend kernel: [4303533.766000]
> ivtv4 warning: ENC Stream 0 OVERFLOW #0: Stealing a Buffer, 512
> currently allocated
>
> But if I increase the buffering---currently I'm running with this
> options ivtv yuv_buffers=16 mpg_buffers=8 vbi_buffers=8
> pcm_buffers=8 dec_osd_buffers=2 and verified as having done
> -something- after a reboot because my syslog went from Jan 17
> 18:15:36 myth-master-backend kernel: [4294696.898000] ivtv4: Allocate
> DMA encoder MPEG stream: 128 x 32768 buffers (4096KB total) Jan 17
> 18:15:36 myth-master-backend kernel: [4294696.899000] ivtv4: Allocate
> DMA encoder YUV stream: 194 x 10800 buffers (2048KB total) Jan 17
> 18:15:36 myth-master-backend kernel: [4294696.900000] ivtv4: Allocate
> DMA encoder VBI stream: 120 x 17472 buffers (2048KB total) Jan 17
> 18:15:36 myth-master-backend kernel: [4294696.901000] ivtv4: Allocate
> DMA encoder PCM audio stream: 455 x 4608 buffers (2048KB total) to
> Jan 18 17:49:39 myth-master-backend kernel: [4294698.245000]
> ivtv4: Allocate DMA encoder MPEG stream: 256 x 32768 buffers (8192KB
> total) Jan 18 17:49:39 myth-master-backend kernel: [4294698.246000]
> ivtv4: Allocate DMA encoder YUV stream: 1553 x 10800 buffers (16384KB
> total) Jan 18 17:49:39 myth-master-backend kernel: [4294698.249000]
> ivtv4: Allocate DMA encoder VBI stream: 480 x 17472 buffers (8192KB
> total) Jan 18 17:49:39 myth-master-backend kernel: [4294698.250000]
> ivtv4: Allocate DMA encoder PCM audio stream: 1820 x 4608 buffers
> (8192KB total) ---then I have two issues:
> (a) the problem hasn't gotten any better, and
> (b) the "ENC Stream 0 OVERFLOW" messages still claim there are only
> 512 buffers, e.g., Jan 18 21:33:21 myth-master-backend kernel:
> [4308167.435000] ivtv4 warning: ENC Stream 0 OVERFLOW #58: Stealing a
> Buffer, 512 currently allocated
>
> Shouldn't the number of allocated buffers -change- between these two
> cases, or is that "512" not reflecting what I think it's reflecting?
>
> (I certainly have less available RAM after booting with more buffers
> than I did before, but I'm beginning to wonder if those buffers
> aren't getting -used- for anything...)
>
> I may try again w/o the yuv buffers and with everything else maxed
> out (I'd like to know if that's a reasonable thing to attempt), but
> it'd be nice to know if the extra RAM is -actually- going to
> buffering...
>
> Note that this is in a system with 5 PVR-250's in it, and that I'm
> also running with "options msp3400 debug=1" in /etc/modprobe.d/ivtv
> as well, FWIW. (I'm superstitious about removing that, since I put
> it in when I first started using ivtv and Myth to track down an
> intermittent problem with no audio on channel 2, and it went away
> after that. I'm afraid removing it might cause some of my recordings
> from that channel to have no audio again...)
The whole buffer allocation code is crap as far as I can tell. I
completely redid the code in the current trunk version of ivtv. You
might try to include the 'max_mpg_buffers=8' module option and see if
that works. I would also recommend upgrading to the latest ivtv-0.4
version.
The long term solution is to upgrade to a 2.6.18 or up kernel. The new,
fixed driver will become available in the near future for that kernel
and up.
Hans
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