[ovs-dev] [PATCH RFC 0/1] dpif-netdev: Make EMC Size Configurable
Loftus, Ciara
ciara.loftus at intel.com
Tue Apr 21 16:01:14 UTC 2015
> -----Original Message-----
> From: Ben Pfaff [mailto:blp at nicira.com]
> Sent: Tuesday, April 21, 2015 4:08 PM
> To: Loftus, Ciara
> Cc: dev at openvswitch.org
> Subject: Re: [ovs-dev] [PATCH RFC 0/1] dpif-netdev: Make EMC Size
> Configurable
>
> On Tue, Apr 21, 2015 at 01:47:12PM +0100, Ciara Loftus wrote:
> > This patch allows the user to specify the number of Exact Match Cache
> > entries they wish to have available for their instance of the vswitch.
> > This is a achieved by means of a 'configure' flag.
> >
> > At the moment, the default number of EMC entries is 1024, for which
> > the switch should perform optimally up to this number of flows.
> > However, if the user expects say roughly 2000 flows of traffic, an EMC
> > with 2048 entries will perform better, allbeit with a larger demand on
> > memory and time spent flushing the cache. If these requirements are
> > acceptable to the user, they may choose to allocate 2048 entries like so,
> > and in turn receive improved performance for their specific use case:
> >
> > './configure --with-emcsize=11'
> >
> > The number of entries is calculated as 2^11 = 2048.
>
> configure flags are really inconvenient. Is there a reason that this
> can't be made configurable at runtime? It would be better yet if the
> EMC size could automatically adjust itself.
Thanks for the feedback. The implementation is naturally more complex for a runtime configurable but I think achievable - I'll look into it.
Thanks,
Ciara
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