2.6.5, 2.6.6-rc2 sluggish interrupts

From: Justin Pryzby
Date: Wed Apr 21 2004 - 13:59:57 EST


I noticed this first with Linux 2.6.5 (but not with 2.6.2) and also now
with 2.6.6-rc2. The machine responds very slugishly while excercizing
one interrupt when another interrupt happens. Ex. I'm circling the
mouse pointer around the screen, and suddenly the hard drive decides to
`sync`, or some such. The pointer then freezes for at least a
half-second. It affects the keyboard too. (Though, presumably, it
could also be a display issue). I notice myself losing alot of
keystrokes as a result of this (I don't know what that means about the
problem..) I don't know enough to say that this is about interrupts,
but take a look:

pryzbyj@andromeda:~$ cat /proc/interrupts
CPU0
0: 3835408 XT-PIC timer
1: 9797 XT-PIC i8042
2: 0 XT-PIC cascade
5: 0 XT-PIC Maestro3
7: 1 XT-PIC parport0
8: 4 XT-PIC rtc
9: 1 XT-PIC acpi
11: 310777 XT-PIC yenta, yenta, uhci_hcd, eth0, r128@PCI:1:0:0
12: 10454 XT-PIC i8042
14: 11802 XT-PIC ide0
15: 17 XT-PIC ide1
NMI: 0
LOC: 0
ERR: 0
MIS: 0

I don't recall seeing that r128@PCI:1:0:0 entry there before (I haven't
changed hardware, I've been using the console framebuffer for a while,
AGP, DRM have always been on). And it seems to be making lots of noise
(though I don't know that that's wrong). I do know there's a general
problem though - sometimes it feels like I'm using a remote machine when
I'm not.

It feels to me like it always happens when the disk is accessed
(possibly just because I can _hear_ that), and it seems like it happens
when the disk hasn't been used in a while.

Please Cc: me.

Justin

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