On Wed, Apr 10, 2019 at 05:35:34PM +0100, Ian Stokes wrote: > On 4/10/2019 5:21 PM, Ian Stokes wrote: > > On 3/5/2019 4:28 PM, Ilya Maximets wrote: > > > 'vhost_id' is an array of 'PATH_MAX' bytes in the middle of > > > 'netdev_dpdk' structure. That is 4K bytes. > > > > > > 'vhost_id' never used on a hot path and there is no need to keep > > > it inside the structure memory. Dynamic allocation will allow to > > > decrease 'struct netdev_dpdk' signigficantly, saving 4KB per ETH > > signigficantly -> significantly > > > port (ETH ports doesn't use 'vhost_id') and almost same value per > > > vhost ports (real 'vhost_id's, in common case, are much shorter). > > > We could save the pointer space by making the union with 'devargs' > > > which is mutually exclusive with 'vhost_id'. > > > As we're just removing the single 'PADDED_MEMBER', the total > > > cacheline layout is not affected. > > > > > > Stats for 'struct netdev_dpdk': > > > > > > Before: /* size: 4992, cachelines: 78 */ > > > After : /* size: 896, cachelines: 14 */ > > > > > > > Thanks Ilya, this looks like a good change, validated without issue. > > > > I've addressed a minor typo in the commit message and comment style > > issue below. Other than that it looks good so applied to master. > > > > On a broader note, do you think it's worth capturing changes such as > > this for users in documentation? i.e. previously the vhost-id path was > > limited to 4096 (however unlikely it was that someone would exceed > > this), but it wasn't captured in the OVS documentation from what I can > > see. From a usability point is it something to document between the 2.10 > > and 2.11 release? > > > > Sorry, meant OVS 2.11 to 2.12 above.
I like to document user-visible changes, but I think in this case it is unlikely to fix any real user problems. (It would be different if we made this change in response to a user having a problem with a very long vhost-id path.) _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev