netdev - Re: [PATCH v2 net-next 0/3] net: Add incoming CPU mask to sockets

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:	Tue, 26 May 2015 11:00:40 -0700
From:	Tom Herbert <tom@...bertland.com>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	"David S. Miller" <davem@...emloft.net>,
	Linux Kernel Network Developers <netdev@...r.kernel.org>
Subject: Re: [PATCH v2 net-next 0/3] net: Add incoming CPU mask to sockets

On Tue, May 26, 2015 at 10:18 AM, Eric Dumazet <eric.dumazet@...il.com> wrote:
> On Tue, 2015-05-26 at 09:34 -0700, Tom Herbert wrote:
>> Added matching of CPU to a socket CPU mask. This is useful for TCP
>> listeners and unconnected UDP. This works with SO_REUSPORT to steer
>> packets to listener sockets based on CPU affinity. These patches
>> allow steering packets to listeners based on numa locality. This is
>> only useful for passive connections.
>>
>> v2:
>>   - Add cache alignment for fields used in socket lookup in sock_common
>>   - Added UDP test results
>
> What about the feedback I gave earlier Tom ???
>
> This cannot work for TCP in its current state.
>
It does work and it fixes cache server locality issues we are seeing.
Right now half of our connections are persistently crossing numa nodes
on receive-- this is having big negative impact. Yes, there may be
edge conditions where SYN goes to a different CPU than the rest of the
flow (probably need RFS or flow director for that problem), and that
sounds like something nice to fix, but this patch is not dependent on
that. Besides, did you foresee an API change would be required?

>
--
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