Re: Real-Time Preemption, -RT-2.6.12-final-V0.7.50-24

Lee Revell
2005-07-13T01:22:06Z

On Mon, 2005-07-04 at 13:16 +0200, Ingo Molnar wrote:
> i'd first suggest to try the latest kernel, before changing your X
> config - i think the bug might have been fixed meanwhile.

I have found that heavy network traffic really kills the interactive
performance. In the top excerpt below, gtk-gnutella is generating about
320KB/sec of traffic.

These priorities do not look right:

14 root -50 -5 0 0 S 0.0 0.0 0:00.00 0 0 0 0 [IRQ 9] irqd
686 root -49 -5 0 0 S 0.0 0.0 87:58.18 0 0 0 0 [IRQ 8] irqd
689 root -48 -5 0 0 S 0.0 0.0 0:00.00 0 0 0 0 [IRQ 7] irqd
694 root -47 -5 0 0 S 0.0 0.0 0:00.00 0 0 0 0 [IRQ 12] irqd
714 root -46 -5 0 0 S 2.5 0.0 5:25.33 0 0 0 0 [IRQ 15] irqd
731 root -45 -5 0 0 S 0.0 0.0 0:04.74 0 0 0 0 [IRQ 1] irqd
3 root -44 -10 0 0 S 0.0 0.0 1:42.55 0 0 0 0 [softirq-timer/0] ksoftirqd
5 root -44 -10 0 0 S 2.5 0.0 5:06.49 0 0 0 0 [softirq-net-rx/] ksoftirqd
1541 root -44 -5 0 0 S 0.0 0.0 9:39.03 0 0 0 0 [IRQ 10] irqd
5650 rlrevell -44 0 2804 1616 S 14.8 0.4 5:52.83 1188 52 784 1 /usr/lib/gamin/gam_server stext
30313 rlrevell -44 0 24572 19m S 99.9 4.4 68:15.42 4520 1800 12m 31 gtk-gnutella stext
2285 root -43 -5 0 0 S 0.0 0.0 3:47.34 0 0 0 0 [IRQ 11] irqd
2807 root -42 -5 0 0 S 0.0 0.0 0:00.00 0 0 0 0 [IRQ 14] irqd
9 root -2 -5 0 0 S 0.0 0.0 0:16.05 0 0 0 0 [events/0] worker_th
4 root 5 -10 0 0 S 0.0 0.0 0:25.95 0 0 0 0 [softirq-net-tx/] ksoftirqd
7 root 5 -10 0 0 S 0.0 0.0 0:01.22 0 0 0 0 [softirq-tasklet] ksoftirqd
8 root 5 -10 0 0 S 0.0 0.0 0:01.30 0 0 0 0 [desched/0] desched_t
28988 root 5 -10 106m 30m S 4.9 6.9 242:59.04 76m 1556 32m 3 /usr/X11R6/bin/X :0 -audit 0 -auth /var/lib/gd stext
2 root 10 -10 0 0 S 0.0 0.0 0:00.00 0 0 0 0 [softirq-high/0] ksoftirqd
6 root 10 -10 0 0 S 0.0 0.0 0:00.00 0 0 0 0 [softirq-scsi/0]

Why do gtk-gnutella and gam_server get a higher priority than the disk
(14) and network (11) IRQs? And shouldn't the softirq threads run at
lower priority than all the hardirq threads?

Looking at the top output I'd expect the machine to be crawling, and
that's what it does.

Lee