[ovs-dev] [PATCH openvswitch v3] netlink: Implement & enable memory mapped netlink i/o
Thomas Graf
tgraf at redhat.com
Wed Dec 4 17:20:53 UTC 2013
On 12/04/2013 05:33 PM, Ben Pfaff wrote:
> If I'm doing the calculations correctly, this mmaps 8 MB per ring-based
> Netlink socket on a system with 4 kB pages. OVS currently creates one
> Netlink socket for each datapath port. With 1000 ports (a moderate
> number; we sometimes test with more), that is 8 GB of address space. On
> a 32-bit architecture that is impossible. On a 64-bit architecture it
> is possible but it may reserve an actual 8 GB of RAM: OVS often runs
> with mlockall() since it is something of a soft real-time system (users
> don't want their packet delivery delayed to page data back in).
>
> Do you have any thoughts about this issue?
That's certainly a problem. I had the impression that the changes that
allow to consolidate multiple bridges to a single DP would minimize the
number of DPs used.
How about we limit the number of mmaped sockets to a configurable
maximum that defaults to 16 or 32?
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