> From: "Ted Unangst" <t...@tedunangst.com> > Date: Thu, 13 Aug 2015 10:04:55 -0400 > > Martin Pieuchot wrote: > > > > How many sparc64 come with em(4)? Can we assume that the amount of > > wasted memory on such system is acceptable? What about other strict- > > alignment architectures? > > just(? mostly?) t5120. mine has 32gb in it. it is, or could be, a popular > openbsd machine. it's also new enough it's almost certainly got memory to > spare, even if you only have 8gb or so. (it does have 4 em, btw.)
The oldest sparc64 machine to ship with onboard em(4) was the t2k, which really isn't such a memory starved machine either. Regarding other strict-alignment architectures, em(4) is probably one of the more popular gigabit ethernet options for those architectures that have PCI slots. I don't think any of these machines are severely memory starved, but memory might be limited to something like 256MB of physical memory. Since we don't fully populate the em(4) rx rings, the memory consumption of the mbufs on the rings isn't going to be very large on interfaces that don't receive a lot of traffic. But I don't have a good idea how likely it is for a lot of received mbufs to be queued up in the network stack.
