Re: USB 2.0 with 250Gb disk and insane loads

[Oliver Neukum]

> > Probably the block layer as it waits for free io slots.
> > But that doesn't tell us why the requests are not executed.
> > Where is SCSI timeout kicking in?
>
> I'm not seeing any scsi timeouts in the logs.

So it seems that the driver doesn't fail utterly, but crawls along.
Storage's debugging output should clarify the situation.

[..]
> > Could you try on USB1.1 only?
>
> Stuck it in an older machine on USB 1.1 and it foudn the disk fine
> (redhat 9, 2.4.20-13.9 kernel on that machine), and ditto result:
>
> 19:15:16  up 2 days, 20:23,  4 users,  load average: 6.02, 2.41, 0.89
> 58 processes: 55 sleeping, 3 running, 0 zombie, 0 stopped
> CPU states:   0.2% user   4.0% system   0.0% nice   0.0% iowait  95.8% idle
> Mem:   385040k av,  380820k used,    4220k free,       0k shrd,   67368k
> buff 224720k active,              69412k inactive
> Swap:  521632k av,      80k used,  521552k free                  237452k
> cached
>
> and generating about 2500 interrupts for the usb controller per 10
> seconds and when i finally break it off and give it "sync" it uses
> about two minutes with about 4500 per 10 seconds to get it all on
> disk. On 2.4 the machine becomes more and more sluggish if I let it go
> more than a short minute.

Which 2.4 ?

	Regards
		Oliver