[mythtv-users] IOBOUND - blocking in ThreadedFileWriter::Write() --- WTH?

[Blammo]

This is getting old:

2006-01-08 14:53:20.087 IOBOUND - blocking in ThreadedFileWriter::Write()
2006-01-08 14:53:21.216 IOBOUND - blocking in ThreadedFileWriter::Write()
2006-01-08 14:53:21.586 IOBOUND - blocking in ThreadedFileWriter::Write()
2006-01-08 14:53:21.666 IOBOUND - blocking in ThreadedFileWriter::Write()
2006-01-08 14:53:29.968 IOBOUND - blocking in ThreadedFileWriter::Write()
2006-01-08 14:53:30.194 IOBOUND - blocking in ThreadedFileWriter::Write()
2006-01-08 14:54:08.315 IOBOUND - blocking in ThreadedFileWriter::Write()
2006-01-08 14:54:49.007 IOBOUND - blocking in ThreadedFileWriter::Write()


I've read all the threads I can find on this topic, with no good
fixes. The only one that seems applicable is the 2M/8M/32M buffer
change for HD content. Before I introduce CVS into my otherwise
completely stable env, I'd like to make sure there's nothing else I
can do.


-- only does it while recording HD content
-- does it more on CBS than other stations
-- seems to have no correlation to cpu load, disk IO, etc.


backend hardware:
Athlon 2400
512M PC3200
NVidia chipset motherboard (NF7-SG)
3ware 9500S-12 w/256M cache, write caching enabled (box is on a UPS)
8x160gb SATA drives
(2) Air2PC HD cards
(1) PVR-250

software:
FC4
myth from yum (0.18.1.20050523-1)


It's doing it as we speak, watching the NFL wildcard game. Just
finished recording/watching the one on fox, not a blip. Now the one on
CBS, I'm averaging a report every 4-5 seconds during the game, not at
all during the commercials. It has the visual effect of  garbage /
stutter / etc on the dedicated frontend I'm watching.

I routinely record 3 programs at the same time, and as long as one of
them isn't high-bit-rate CBS (csi miami for example) there's zero
problems.


vmstat -d
sda   13634885  33356 2575506290 508342252 12288617 1775750 1620207680
879929132      0  96712

procinfo -n10 -d
Memory:      Total        Used        Free      Shared     Buffers
Mem:             0         -33          33           0           0
Swap:            0           0           0

Bootup: Tue Dec 20 15:31:33 2005    Load average: 1.60 1.81 1.88 1/177 382

user  :       0:00:00.46   1.8%  page in :        0
nice  :       0:00:00.00   0.0%  page out:        0
system:       0:00:01.74   7.0%  swap in :        0
idle  :       0:00:07.81  31.2%  swap out:        0
uptime:  18d 23:37:19.00         context :    239864

irq  0:      2500 timer                 irq  9:         0 acpi
irq  1:         0 i8042                 irq 10:     27624 ivtv0, eth0
irq  2:         0 cascade [4]           irq 11:      4930 Technisat/B2C2 FlexC
irq  3:       623 3w-9xxx               irq 12:         0 i8042
irq  7:       867 Technisat/B2C2 FlexC  irq 14:         3 ide0
irq  8:         0 rtc


The only tuner recording anything right now is the IRQ11 device. The
eth0 traffic is coming from my watching it while it's recording.

I'm getting what I would consider (based on where I've come from)
great results from the RAID array:

[root at backend1 ~]# bonnie++ -d /raid/temp -u0 -g0 -n0 -s 1024
Using uid:0, gid:0.
Writing with putc()...done
Writing intelligently...done
Rewriting...done
Reading with getc()...done
Reading intelligently...done
start 'em...done...done...done...
Version  1.03       ------Sequential Output------ --Sequential Input- --Random-
                    -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec %CP
backend1         1G 30144  85 41942  23 25496  14 35914  90 116390  38 560.8   4
backend1,1G,30144,85,41942,23,25496,14,35914,90,116390,38,560.8,4,,,,,,,,,,,,,

Ahh, one last note, I'm running elevator=deadline.

what the hell is going on?