netdev - RE: [PATCH 3/7] mlx4_en: Incoming traffic alignment optimizations

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: <953B660C027164448AE903364AC447D2235EEB7E@MTLDAG01.mtl.com>
Date:	Tue, 18 Oct 2011 07:43:08 +0000
From:	Yevgeny Petrilin <yevgenyp@...lanox.co.il>
To:	Eric Dumazet <eric.dumazet@...il.com>
CC:	"davem@...emloft.net" <davem@...emloft.net>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: RE: [PATCH 3/7] mlx4_en: Incoming traffic alignment optimizations

> 
> > @@ -91,7 +91,7 @@
> >  /* Receive fragment sizes; we use at most 4 fragments (for 9600 byte MTU
> >   * and 4K allocations) */
> >  enum {
> > -	FRAG_SZ0 = 512 - NET_IP_ALIGN,
> > +	FRAG_SZ0 = 2048,
> >  	FRAG_SZ1 = 1024,
> >  	FRAG_SZ2 = 4096,
> >  	FRAG_SZ3 = MLX4_EN_ALLOC_SIZE
> 
> Is the 512 -> 2048 change really wanted ? Its not mentioned in changelog and is confusing.
> 
> This means mlx4 lost the ability to use a small frag (512 bytes) to store small frames.
> 
The change is wanted as an optimization for our HW.
We do get better numbers with this change, even with small packets.
You are correct, I should have mentioned it in the changelog.

Yevgeny