Robert Schaefer wrote:
> 
> ----- Original Message ----- From: "Mark Cullen" <mark.r.cullen@gmail.com>
> To: <netbsd-users@NetBSD.org>
> Sent: Friday, July 21, 2006 11:27 AM
> Subject: Re: 3.0.1: softdep + ffsv2 + 'heavy' load = pauses
> 
> 
>> Mark Cullen wrote:
>>
>> LCDProc was still running fine, and the LCD on the machine was showing 
>> ~70% idle CPU at the time, so perhaps processes were getting wedged 
>> waiting for the disk or something? Perhaps it is something to do with 
>> RAIDFrame? The test machine is not running on a RAID-1 array like this 
>> box, and only has one 'fxp' card as opposed to two. Who knows! The 
>> hardware configurations differ quite a lot, and the test box (which 
>> doesn't hang, even with 400 clients) doesn't have all of the stuff the 
>> home server has running. It just runs the same kernel.
> 
> This matches exactly a reoccuring problem I've suffered from since 1.6 
> IIRC. I thought it went away when I upgraded to 3.0 (GENERIC.MP from Dec 
> 19, '05), but it came back...coincidentally about the same time I turned 
> on softdeps.
> 
> My machine is a 4-way PPRo box with 512MB ram, 6 disks on 2 aha(4) 
> busses. The only ata device is the cdrom, it's rarely mounted. Three 
> disks are configured as a raid 5 drive mounted as /export and /home/www 
> and /tmp is mfs. fxp0 is up and bound to both an IPv4 and IPv6 address, 
> although only IPv4 addressing is in use. fxp1 and fea0 are currently 
> unused.
> 
>>
>> I have disabled softdep on all mounts now and I am giving 
>> BUFQ_PRIOCSCAN a try. Hopefully it won't hang this time, but I 
>> shalln't be able to test until tonight.
> 
> I'll try turning off softdeps and see if the problem goes away.
> 

I'm fairly sure softdep is the cause of this problem. My system now 
feels far, far more responsive without softdep on any of the mounts, 
while doing cvs updates and such. There's no annoying 10 second pauses 
when trying to run things or anything!

I'm not sure if the BUFQ_PRIOCSCAN option is doing anything beneficial 
though. I'm not even sure it's a 'stable' option to use really, I can't 
find much mention of it.

Let us know if turning off softdep's improves the situation for you!

-- 
Mark Cullen <mark.r.cullen@gmail.com>