Hard disk speed - Maybe OT

Well its on a SuSE system...

I am trying to squeeze a bit more I/O bandwidth out of a video processing box w/out changing the hardware. Have a look at this dreadful procinfo.

linux 2.6.11.4-21.17-default (geeko@buildhost) (gcc 3.3.5 20050117) #1 Fri Apr 6 08:42:34 UTC 2007 1CPU [wcethopes3.]

Memory: Total Used Free Shared Buffers
Mem: 255416 138680 116736 0 90028
Swap: 522072 8384 513688

Bootup: Sat Jun 7 12:11:32 2008 Load average: 3.02 5.18 4.48 1/60 9517

user: 8d 7:49:32.61 21.7% page in: 662448590 disk 1: 2396196r3256073w
nice: 1d 9:19:12.01 3.6% page out: 1239648452 disk 2: 21758237r144550637w
system: 3d 9:19:51.07 8.8% page act: 338016275 disk 3: 21515776r116912910w
IOwait: 14d 7:12:00.73 37.3% page dea: 267210034
hw irq: 9:34:16.62 1.0% page flt: 1424451211
sw irq: 6:19:26.88 0.7% swap in : 41230
idle : 10d 6:54:50.34 26.8% swap out: 19971
uptime: 38d 8:29:33.50 context : 2432943939

irq 0:3314254056 timer irq 9: 1 acpi, uhci_hcd
irq 1: 96 i8042 irq 11:1893463035 eth0
irq 2: 0 cascade [4] irq 12: 3
irq 6: 33 irq 14: 5652276 ide0
irq 7: 1 parport0 [3] irq 15: 377573222 ide1
irq 8: 2 rtc

(Sorry about the formatting)

Notice the huge amount of I/O wait time. There are two basic main processes that run on the box, one is a capture system and the other creates MPEG's. They are pretty I/O intensive. Nicing helps one over the other (the capture is kind of time critical) but not dramatically so. I think it is I/O bound!

There are three disks. hda is a ATA33 and hdc/hdd are ATA6 RAID0. It was a cruel choice having to put both ATA6 drives on the secondary channel but I didn't want one slowed by the ATA33.

I have done the usual things with hdparm, turning off acoustic management 32 bit sync etc etc. Still have problems.

Was considering playing with buffer flushing times or maybe the file system itself. It is running vanilla reiser.

Its a P3/933 with an Intel 815 chipset. It also has two other boxes talking NFS to it doing the same MPG processing. (Kind of like clustering. We originally had a cpu/grunt/time to process problem that has now gone away in favour of the I/O congestion!)

I am looking for any useful speedup suggestions. If I cant find a solution I'll have to do some pgm rewrite/rethinks. Hardware changes are not an option. I also wonder if there is a way to "nice" a process for less I/O use rather than cpu slices...

TIA Bob
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