fixing IRQ storms

Mike Tancsa mike at sentex.net
Fri Apr 6 12:28:21 UTC 2007


At 08:13 AM 4/6/2007, Volker wrote:

>Mike,
>
>have a look at GNAT: http://www.freebsd.org/cgi/query-pr.cgi?pr=51982
>
>You need to patch your kernel sources a bit (all info in the PR) and
>your silo overflows will be gone. I've done that to get a Merlin
>U630 working (w/o patching sio.c the card was almost unusable).

Hi,
         Thanks for the note.  Actually, I have done this in the past 
(I am even in the above PR :)), but I had found using the UART driver 
instead of sio was better for working around such issues on the 
whole.  The overflow rate is so high in the case, even increasing the 
ticks by 10 doesnt seem to fix the issue. It seems to reduce the 
overflows a bit, but nowhere nearly enough

sio2: 108 more interrupt-level buffer overflows (total 108)
sio2: 81 more interrupt-level buffer overflows (total 189)
sio2: 108 more interrupt-level buffer overflows (total 297)
sio2: 81 more interrupt-level buffer overflows (total 378)
sio2: 33 more interrupt-level buffer overflows (total 411)
sio2: 76 more interrupt-level buffer overflows (total 487)

With the uart driver, I am able to talk to the modem OK, but the cpu 
is really high dealing with all those interrupts.

I was hoping I could just tell the card to use a different interrupt 
like 5 which is available, but I dont know how to do that, or if its 
even possible.

         ---Mike 



More information about the freebsd-hackers mailing list