On Wed, Feb 19, 2014 at 11:04:49PM +0200, Alexander Motin wrote: > On 19.02.2014 22:04, Adrian Chadd wrote: > > On 19 February 2014 11:59, Alexander Motin <m...@freebsd.org> wrote: > > > >>> So if we're moving towards supporting (among others) a pcbgroup / RSS > >>> hash style work load distribution across CPUs to minimise > >>> per-connection lock contention, we really don't want the scheduler to > >>> decide it can schedule things on other CPUs under enough pressure. > >>> That'll just make things worse. > > > >> True, though it is also not obvious that putting second thread on CPU run > >> queue is better then executing it right now on another core. > > > > Well, it depends if you're trying to optimise for "run all runnable > > tasks as quickly as possible" or "run all runnable tasks in contexts > > that minimise lock contention." > > > > The former sounds great as long as there's no real lock contention > > going on. But as you add more chances for contention (something like > > "100,000 concurrent TCP flows") then you may end up having your TCP > > timer firing stuff interfere with more TXing or RXing on the same > > connection. > > 100K TCP flows probably means 100K locks. That means that chance of lock > collision on each of them is effectively zero. More realistic it could
What about 100K/N_cpu*PPS timer's queue locks for remove/insert TCP timeouts callbacks? _______________________________________________ firstname.lastname@example.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"