Hi Richard, On Tue, Oct 27, 2015, at 11:11, Richard Cochran wrote: > On Mon, Oct 26, 2015 at 02:32:59PM +0100, Hannes Frederic Sowa wrote: > > On Mon, Oct 26, 2015, at 14:19, Richard Cochran wrote: > > > On Mon, Oct 26, 2015 at 01:51:37PM +0100, Hannes Frederic Sowa wrote: > > > > netstamp_needed is toggled for all socket families if they request > > > > timestamping. But some protocols don't need the lower-layer timestamping > > > > code at all. This patch starts disabling it for af-unix. > > > > > > What problem is this patch trying to solve? > > > > netstamp_needed is a static-key which enables timestamping code in the > > networking stack receive functions for every packet, while it is not > > needed for AF_UNIX/LOCAL. So it is merely a small performance > > enhancement. > > Are there any numbers that show the effect of this enhancement?
I haven't personally done any performance numbers. Jesper (in Cc) noticed that it showed up in perf performance reports even though he used a very minimal setup. Turned out that systemd-journald enables timestamping on AF_UNIX sockets which thus enabled netstamps globally. I think Jesper can chime in here. Bye, Hannes -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
