On Tue, Oct 2, 2018 at 6:28 AM Andres Freund <and...@anarazel.de> wrote: > On 2018-10-01 19:25:45 +0200, Matteo Beccati wrote: > > On 01/10/2018 01:09, Thomas Munro wrote: > > > I don't know why the existence of the kqueue should make recvfrom() > > > slower on the pgbench side. That's probably something to look into > > > off-line with some FreeBSD guru help. Degraded performance for > > > clients on the same machine does seem to be a show stopper for this > > > patch for now. Thanks for testing! > > > > Glad to be helpful! > > > > I've tried running pgbench from a separate VM and in fact kqueue > > consistently takes the lead with 5-10% more tps on select/prepared pgbench > > on NetBSD too. > > > > What I have observed is that sys cpu usage is ~65% (35% idle) with kqueue, > > while unpatched master averages at 55% (45% idle): relatively speaking > > that's almost 25% less idle cpu available for a local pgbench to do its own > > stuff. > > This suggest that either the the wakeup logic between kqueue and poll, > or the internal locking could be at issue. Is it possible that poll > triggers a directed wakeup path, but kqueue doesn't?
I am following up with some kernel hackers. In the meantime, here is a rebase for the new split-line configure.in, to turn cfbot green. -- Thomas Munro http://www.enterprisedb.com
0001-Add-kqueue-2-support-for-WaitEventSet-v12.patch
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