High interrupt CPU usage in top
Mark Cullen
mark.r.cullen at gmail.com
Wed Jun 7 14:42:09 PDT 2006
Matthew Dillon wrote:
:Well, world and kernel just finished compiling, without INVARIANTS, and
:there's no difference. Infact, it seems worse... but it's probably the
:same. I guess I should keep INVARIANTS in for debugging in case of panics?
:
:http://img198.imageshack.us/img198/1571/interrupt3eg.jpg
:
:40% and very few interrupts? That was just starting out compiling
:`mysql4-server`.
INVARIANTS is pretty light weight, it won't make much of a difference.
Try doing some basic tests to exercise JUST the network adapter, like
running a 'ping -i 0.1 <target>'. And some tests to exercise JUST your
hard disk, like doing a few cpdup's or a tar or something.
If its the disk, check your dmesg output to whether the ATA driver is
using DMA or not.
-Matt
Matthew Dillon
<dillon at xxxxxxxxxxxxx>
Well, `ping -i 0.1 <t>` got me less than 1%. However, `ping -f <t>` got
me 35%.
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 at bone2)/usr/pkg/etc atacontrol mode 0
Master = ???
Slave = WDMA2
(root at 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?
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