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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 28 Jan 2009 14:55:51 +0100
From:	Eric Dumazet <dada1@...mosbay.com>
To:	Rick Jones <rick.jones2@...com>
CC:	Netfilter Developers <netfilter-devel@...r.kernel.org>,
	Patrick McHardy <kaber@...sh.net>,
	Linux Network Development list <netdev@...r.kernel.org>,
	Stephen Hemminger <shemminger@...tta.com>
Subject: Re: 32 core net-next stack/netfilter "scaling"

Rick Jones a écrit :
>>> 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.
>

Yes indeed you have a speedup, tcp conntracking is OK.

You now hit the nf_conntrack_lock spinlock we have in generic conntrack code 
(net/netfilter/nf_conntrack_core.c)

nf_ct_refresh_acct() for instance has to lock it.

We really want some finer locking here.

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html