Re: Large amounts of memory access operations cause panic under CURRENT (was "Large gap between fwrite and write, and fread and read")

>> Go figure it'd cause panics for other people.
>> 
>> I wasn't using zfs at all but it panicked anyhow once (my amd64 VM only, 
>> not my i386 test server, surprisingly). I wish I'd gotten the panic but I 
>> walked away to get a glass of water, and there wasn't a core dump because 
>> the VM shut down completely instead of restarting. Heh.
>> 
>> My virtual machine died around 90k on the first trial though. I'll be sure 
>> to reduce the amount and see what happens, and I'll put nanosleeps or 
>> usleeps between the read and write ops to see if that alleviates the race 
>> condition seen, but I'll keep the problem code around for reference later 
>> in case I've stimulated some sort of weird bug in FreeBSD, or otherwise.
>> 
>> Both my VM and test server run almost no programs though other than samba 
>> and rsync, so you'll probably see the panic faster / more frequently than I 
>> will if you run a lot more programs resident in memory.
>> 
>> Just curious, what scheduler are you using on CURRENT, what processor do 
>> you have, and what are your memory specs?
>> 
>> Thanks,
>> -Garrett
>> 
> Hi Garrett,
> 
> this is just my desktop where is running only Xorg, fluxbox, few aterms and
> firefox. But i can get the panic on console too, shortly after booting. I'm
> using SCHED_ULE.
> 
> CPU: AMD Athlon(tm) 64 X2 Dual Core Processor 4200+ (2205.01-MHz K8-class
> CPU)
>   Origin = "AuthenticAMD"  Id = 0x20f32  Stepping = 2
>   Features=0x178bfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,MMX,FXSR,SSE,SSE2,HTT>
>   Features2=0x1<SSE3>
>   AMD Features=0xe2500800<SYSCALL,NX,MMX+,FFXSR,LM,3DNow!+,3DNow!>
>   AMD Features2=0x3<LAHF,CMP>
>   Cores per package: 2
> usable memory = 3211718656 (3062 MB)
> avail memory  = 3105570816 (2961 MB)
> 
> For the record, it crashes few times before it hit 100k iterations, before i
> put
> debug printf in your code and increase MAX_ITERATIONS to 1m. And as far as I
> can tell, I had pretty much the same results as you've measured.
> 
> mv

Sorry for the noise, forgot to CC current_at_