On Tue, May 17, 2016 at 01:34:34PM -0400, Doug Ledford wrote: > > I noticed this too, but for sysfs reading I just felt it doesn't > > matter. > > I prefer not to have O(n^2), even for sysfs. You say it doesn't matter, > but if someone creates a script to check all of their stats via > sysfs Well, it matters if it actually takes a long time, but I don't really care of it is O(n^2) and still only adding a few additional 100us's.. > > and nothing should use sysfs except > > debugging. > > Nobody manually checking on numbers themselves will use netlink. And if > the stats are there, people will check them. You can't depend on this > being used for debug access only. If I recall correctly, ibstatus uses > all sysfs entries, and people would easily think that using it uses the > "preferred" method. So, like I said, if it's there, it *will* get used, > and not just for debug, Why would people manually use sysfs? A netlink interface would be accompanied by a tool. I don't schlep around in sysfs for netdev, I use 'ip -s link show' > > Caching is going to detrimental to apps that sync stats with external > > time. (which is almost every real-world app) > > That's problematic with or without caching as the stats don't have a > timestamp, so scheduling delays could easily make the stats that you > get One can avoid scheduling delays with the right SCHED_ policy, how do you avoid timing jitter from caching? Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
