netdev - Re: [PATCH v3 net-next 0/4] net: batched receive in GRO path

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]

Message-ID: <a7362654-a47b-1ba9-24d1-227adbe3c7ed@gmail.com>
Date:   Wed, 14 Nov 2018 23:22:37 -0800
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Edward Cree <ecree@...arflare.com>,
        linux-net-drivers@...arflare.com, davem@...emloft.net
Cc:     netdev@...r.kernel.org
Subject: Re: [PATCH v3 net-next 0/4] net: batched receive in GRO path

On 11/14/2018 10:07 AM, Edward Cree wrote:
>
> Conclusion:
> * TCP b/w is 16.5% faster for traffic which cannot be coalesced by GRO.
>

But only for traffic that actually was perfect GRO candidate, right ?

Now what happens if all the packets you are batching are hitting different TCP sockets ?

(DDOS attack patterns)

By the time we build a list of 64 packets, the first packets in the list wont be anymore
in L1 cache (32 KB 8-way associative typically), and we will probably have cache trashing.