netdev - Re: [Xen-devel] [RFC PATCHv1 net-next] xen-netback: always fully coalesce guest Rx packets

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: <1421752993.10440.225.camel@citrix.com>
Date:	Tue, 20 Jan 2015 11:23:13 +0000
From:	Ian Campbell <Ian.Campbell@...rix.com>
To:	David Vrabel <david.vrabel@...rix.com>
CC:	Wei Liu <wei.liu2@...rix.com>, <netdev@...r.kernel.org>,
	<xen-devel@...ts.xenproject.org>,
	Jonathan Davies <jonathan.davies@...rix.com>
Subject: Re: [Xen-devel] [RFC PATCHv1 net-next] xen-netback: always fully
 coalesce guest Rx packets

On Mon, 2015-01-19 at 17:36 +0000, David Vrabel wrote:
> On 13/01/15 14:30, Wei Liu wrote:
> > On Tue, Jan 13, 2015 at 02:05:17PM +0000, David Vrabel wrote:
> >> Always fully coalesce guest Rx packets into the minimum number of ring
> >> slots.  Reducing the number of slots per packet has significant
> >> performance benefits (e.g., 7.2 Gbit/s to 11 Gbit/s in an off-host
> >> receive test).
> >>
> > 
> > Good number.
> > 
> >> However, this does increase the number of grant ops per packet which
> >> decreases performance with some workloads (intrahost VM to VM)
> > 
> > Do you have figures before and after this change?
> 
> Some better (more rigorous) results done by Jonathan Davies shows no
> regressions with full coalescing even without the grant copy
> optimization, and a big improvement to single stream receive.
> 
>                          baseline    Full coalesce
> Interhost aggregate      24 Gb/s     24 Gb/s
> Interhost VM receive      7.2 Gb/s   11 Gb/s
> Intrahost single stream  14 Gb/s     14 Gb/s
> Intrahost aggregate      34 Gb/s     34 Gb/s

Do you have a third column to hand, for Full-coalesce w/ grant copy
optimisation case? (Don't worry if not)

Ian.

--
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