Re: High interrupt CPU usage in top

[Mark Cullen <mark.r.cullen@xxxxxxxxx>]

Matthew Dillon wrote:
> :As for disk, a very simple `dd if=/dev/<d> of=/dev/null` gets me ~25%, 
> :and as far as I can see DMA is enabled.
> :
> :---
> :(root@bone2)/usr/pkg/etc atacontrol mode 0
> :Master = ???
> :Slave  = WDMA2
> :(root@bone2)/usr/pkg/etc atacontrol mode 1
> :Master = ???
> :Slave  = UDMA33
> :---
> :
> :As you can see, a bit of a mix up there, CD drive is primary slave and 
> :the hard disk is secondary slave. However, before you blame it on 
> :this... my last install (just yesterday actually) was a 30GB disk on 
> :primary master and has the exact same behaviour.
> :
> :I ran the same commands on the 4.11 box (different motherboard / chipset 
> :but that's it) and `ping -f <t>` is around 17% and the simple dd is the 
> :same, +- a few percent. Both have polling enabled, and both are using 
> :identical Intel NIC's, two in each machine.
> :
> :Any of that info is worth anything to anyone?
>
>     IDE doesn't really support devices that are only on the slave, with
>     no master.  At least, not reliably.  You have to make both of them
>     the master. 
>
>     It is either the cable or a jumper on the drive.   Try fixing that and
>     see if it boots with DMA turned on.
>
> 					-Matt
> 					Matthew Dillon 
> 					<dillon@xxxxxxxxxxxxx>

It does boot with DMA turned on, unless I am missing something? The 
WDMA2 drive is the old CD drive, the UDMA33 drive is the hard disk. :-)