[ovs-dev] [PATCH RFC 0/1] dpif-netdev: Make EMC Size Configurable

Ben Pfaff blp at nicira.com
Tue Apr 21 15:07:46 UTC 2015


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.



More information about the dev mailing list