netdev - Re: [PATCH 00/16] Remove the ipv4 routing cache

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, 25 Jul 2012 19:30:13 -0700
From:	Alexander Duyck <alexander.duyck@...il.com>
To:	David Miller <davem@...emloft.net>
Cc:	eric.dumazet@...il.com, netdev@...r.kernel.org
Subject: Re: [PATCH 00/16] Remove the ipv4 routing cache

On Wed, Jul 25, 2012 at 5:54 PM, David Miller <davem@...emloft.net> wrote:
> From: David Miller <davem@...emloft.net>
> Date: Wed, 25 Jul 2012 16:39:39 -0700 (PDT)
>
>> From: David Miller <davem@...emloft.net>
>> Date: Wed, 25 Jul 2012 16:17:32 -0700 (PDT)
>>
>>> From: Alexander Duyck <alexander.duyck@...il.com>
>>> Date: Wed, 25 Jul 2012 16:02:45 -0700
>>>
>>>> Since your patches are in I have started to re-run my tests. I am
>>>> seeing a significant drop in throughput with 8 flows which I expected,
>>>> however it looks like one of the biggest issues I am seeing is that
>>>> the dst_hold and dst_release calls seem to be causing some serious
>>>> cache thrash.  I was at 12.5Mpps w/ 8 flows before the patches, after
>>>> your patches it drops to 8.3Mpps.
>>>
>>> Yes, this is something we knew would start happening.
>>>
>>> One idea is to make cached dsts be per-cpu in the nexthops.
>>
>> Actually I think what really kills your case is the removal of the
>> noref path for route lookups.  I'll work on a patch to restore that
>> in the case where we use cached routes from the FIB nexthops.
>
> Alex, here is something I tossed together, does it help with the
> dst_hold()/dst_release() overhead at all?
>

I downloaded your patch, applied it, rebuilt the kernel, and then
rebooted.  However after the reboot I am unable to access the system
remotely.  It looks like I will have to wait until I get into the
office tomorrow to figure out what happened to the system.

I will get you an update on if it helped or not once I figure out what
happened in the morning.

Thanks,

Alex
--
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