Subject: Re: 32 core net-next stack/netfilter "scaling"

From: Rick Jones <[email-masked]>
Date: Tue, 27 Jan 2009 11:24:54 -0800

>> I will give it a try and let folks know the results - unless told 
>> otherwise, I will ass-u-me I only need rerun the "full_iptables" test 
>> case.
> 
> 
> The runemomniagg2.sh script is still running, but the initial cycles 
> profile suggests that the main change is converting the write_lock time 
> into spinlock contention time with 78.39% of the cycles spent in 
> ia64_spinlock_contention. When the script completes I'll upload the 
> profiles and the netperf results to the same base URL as in the basenote 
> under "contrack01/"

The script completed - although at some point I hit an fd limit - I think I have 
an fd leak in netperf somewhere :( .

Anyhow, there are still some netperfs that end-up kicking the bucket during the 
run - I suspect starvation because where in the other configs (no iptables, and 
empty iptables) each netperf seems to consume about 50% of a CPU - stands to 
reason - 64 netperfs, 32 cores - in the "full" case I see many netperfs consuming 
100% of a CPU.  My gut is thinking that one or more netperf contexts gets stuck 
doing something on behalf of others.  There is also ksoftirqd time for a few of 
those processes.

Anyhow, the spread on trans/s/netperf is now 600 to 500 or 6000, which does 
represent an improvement.

rick jones

PS - just to be certain that running-out of fd's didn't skew the results I'm 
rerunning the script with ulimit -n 10240 and will see if that changes the 
results any.  And I suppose I need to go fd leak hunting in netperf omni code :(