Date: Sat, 28 Jun 2014 13:21:37 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Palle Girgensohn <girgen@pingpong.net> Cc: "freebsd-current@freebsd.org" <freebsd-current@freebsd.org>, "performance@freebsd.org" <performance@freebsd.org> Subject: Re: PostgreSQL performance on FreeBSD Message-ID: <20140628102137.GA93733@kib.kiev.ua> In-Reply-To: <35090A62-2DB8-493C-A5ED-ADB1BC193640@pingpong.net> References: <20140627125613.GT93733@kib.kiev.ua> <201406271057.53599.jhb@freebsd.org> <20140627163407.GX93733@kib.kiev.ua> <35090A62-2DB8-493C-A5ED-ADB1BC193640@pingpong.net>
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[-- Attachment #1 --] On Sat, Jun 28, 2014 at 12:08:39PM +0200, Palle Girgensohn wrote: > > > 27 jun 2014 kl. 18:34 skrev Konstantin Belousov <kostikbel@gmail.com>: > > > On Fri, Jun 27, 2014 at 10:57:53AM -0400, John Baldwin wrote: > >> On Friday, June 27, 2014 8:56:13 am Konstantin Belousov wrote: > >>> Hi, > >>> I did some measurements and hacks to see about the performance and > >>> scalability of PostgreSQL 9.3 on FreeBSD, sponsored by The FreeBSD > >>> Foundation. > >>> > >>> The results are described in https://kib.kiev.ua/kib/pgsql_perf.pdf. > >>> The uncommitted patches, referenced in the article, are available as > >>> https://kib.kiev.ua/kib/pig1.patch.txt > >>> https://kib.kiev.ua/kib/patch-2 > >> > >> Did you run the same benchmark on the same hardware with any other OS's to > >> compare results? > > > > No. > > > > FWIW, before the failing after the 30 clients is corrected, I do not > > think it is much interesting to do such comparision. > > This is great work! > > Does anybody know how far back in FreeBSD versions using posix semaphore instead of sysv would make a difference? It seems we need a rather current version? 8.x did not support it at all, at some point at lest, and in 9 it was buggy. I could add he patch-2 to the port, but I reckon it needs a conditional based on FreeBSD version? > I recommend to add it as an option. The currently supported versions of stable/9 and higher have new posix semaphores implementation. The stable/8 also has posix semaphores, but there it is kernel-based interface, I do not plan to evaluate it in any way. > The clang bug should go upstreams, right? I believe there is already some activity about it. I do not follow clang development. > > I have seen similar curves, presented by Greg Smith (PostgreSQL > hacker) where he concluded that there is no point in running more > than 50 concurrent connections. This was for Linux. In your measures, > the knee is at 30. That's said, FreeBSD could and should do better, > but probably there is a limit where there will be a knee in the graph > and performance will drop. It should be more than 30, though, as you > rightly commented. > > Do you any ideas to pursue this further apart from complicated > rewrites like DragonFly? > I do. The scope of the current work was done to obtain understanding where do we stay and, if possible, evaluate ideas, possibly in the hackish way. I hope and almost sure that this will be continued, but cannot provide any time estimation. [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBAgAGBQJTrpcxAAoJEJDCuSvBvK1BYE8P/RYeGpegRSM7KT2+HlrW2zRO nGiXx7phK6+CJtUdzOvgrhuHkniI0e54t6qPF8q1XTtVNnPC+5nMWGuNoeJrMfPu +R29XDGcFNONovDDsbIuQgNq1J9foIQyKY6zFlgXl2jTtzuv2hwBoVP/BJ18mKRO ly51Ys+gRFQmdCcsU3GD+tp4q5VesNdOes9V3CBefEXNZPnFPgtULNh+mfVd+0aS jXfMo/2SRecUXG0rWBnB+5qJlySTJUmMzsaBaiWjTPQ0IlrMVcOTcwxc2cqM0GMt ihrPzdUEXoKZQt8qa36Otb71dcKdxQQVFjOf7aQMRbg4C66m2vwTIbAFurJnh8m/ GtAc9ebvYUBeAsqz2I6aacjfFCgc/Lg3dkLf5h0sCGfQoF8KhO0UGbSjWhPDmHw1 2MFIWs1q/gVsXgtpG2rnHwgEGVDbUQB/NwA8lwqyzU/x1+He2g8cT+Q2SO2dfa9u NEXoZhH7mJvbRQbXaJ+zhthtRC/wAr6RwWYA+T64/1RJxMv8Y2fjwMykYxVDQI6C rC3dddI+tgNOxe4hzoxLAd89K4kU0yA/xSz3q5pmZc/MO7bZ7zH1e26SwpGP5/yo TNTsNuo+buZUYqLvHYpbBwA0D+Uu/AGH14vkKpOJjoZAGd6/amt6jrX3rgJGVOYK sdGFeytYByDakUQfLu1H =3QOa -----END PGP SIGNATURE-----
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