Date: Tue, 20 May 2014 17:13:50 -0700 From: =?UTF-8?Q?Gezeala_M=2E_Bacu=C3=B1o_II?= <gezeala@gmail.com> To: Palle Girgensohn <girgen@pingpong.net> Cc: Adrian Chadd <adrian@freebsd.org>, "bsdmailinglist@googlegroups.com" <bsdmailinglist@googlegroups.com>, Petr Janda <janda.petr@gmail.com>, Steven Hartland <killing@multiplay.co.uk>, FreeBSD Mailing Lists <freebsd-performance@freebsd.org>, Sean Chittenden <sean@chittenden.org> Subject: Re: FreeBSD 10 and PostgreSQL 9.3 scalability issues Message-ID: <CAJKO3mUTwgiQenSLYfOxHrZxuPQ9kvUPC44MrbLjvpLE=toZQA@mail.gmail.com> In-Reply-To: <572540F9-13E4-4BA9-88AE-5F47FB19450A@pingpong.net> References: <5327B9B7.3050103@gmail.com> <2610F490C952470C9D15999550F67068@multiplay.co.uk> <532A192A.1070509@gmail.com> <assp.0155c70d29.23ED6415-945D-4DF5-90DD-2F2CD7E198AF@chittenden.org> <f4ead73a-fae2-4eac-8499-3cf630eb3d31@googlegroups.com> <CAJ-VmomVOWFb7X5s-amRX7QFzbmT6Kt6bB9gaPVv2_hGx1OS5g@mail.gmail.com> <572540F9-13E4-4BA9-88AE-5F47FB19450A@pingpong.net>
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Do you guys have any updates on this? -- regards gezeala bacu=C3=B1o II On Tue, Apr 22, 2014 at 11:52 PM, Palle Girgensohn <girgen@pingpong.net>wro= te: > > > > 23 apr 2014 kl. 01:04 skrev Adrian Chadd <adrian@freebsd.org>: > > > > Hi, > > > > Are you able to repeat these tests (for both 9.2 and 9.3) whilst > > grabbing some performance data from lock profiling and hwpmc? > > I sure can, but I'd love some pointers as to how this is done. Please? :-= ) > > > > > The benchmarking is great but it doesn't tell us enough information as > > to "why" things behave poorly compared to Linux and why the mmap drop > > isn't so great. > > > As per the discussion on postresql-hackers, the regression between pg9.2 > and pg9.3, which includes the sysv->mmap shift, *might* also exist, at > least partly, on Linux as well. > > The initial post in *this* thread does however indicate that freebsd > performs poorer than Linux and dragonflybsd, but does not really compare > PostgreSQL versions. > > Just so we're not pursuing the wrong problem here, let's be open minded > about the definition of the problem. :-) > > > > > What about with more clients? 64? 128? 256? > > My test went to 80. I can go higher as well, though other sources say 50 > is a reasonable limit for PostgreSQL. > > Palle > > > > > > > > Thanks! > > > > > > > > -a > > > > > >> On 21 April 2014 14:11, Palle Girgensohn <girgen@pingpong.net> wrote: > >> > >> > >>> Den torsdagen den 20:e mars 2014 kl. 00:33:10 UTC+1 skrev Sean > Chittenden: > >>> > >>>> As far as I know, the test was done on both UFS2 and ZFS and the > >>>> difference was marginal. > >>> > >>> As Adrian pointed out, there is an mmap(2) mutex in the way. Starting > in > >>> PostgreSQL 9.3, shared buffers are allocated out of mmap(2) instead o= f > shm. > >>> shm is only used to notify the PostgreSQL postmaster that a child > process > >>> exited/crashed (when a pid detaches from a shm segment, there is a > kernel > >>> event, but there is no kernel event when detaching from an mmap(2) > region). > >>> -sc > >>> > >>> http://www.postgresql.org/docs/9.3/static/release-9-3.html#AEN115039 > >>> > >>> > >>>>>> Just want to share these pgbench results done by DragonFlyBSD, and > >>> would > >>>>>> like some input on why these numbers look so bad and what can be > done > >>> to > >>>>>> improve (ie. kernel tunables etc) the performance. > >>> > http://lists.dragonflybsd.org/pipermail/users/attachments/20140310/4250b9= 61/attachment-0001.pdf > >>>>> > >>>>> > >>>>> Do you have the ability to test with FreeBSD 8.x and 9.x to see if > this > >>> is > >>>>> regression? > >>>>> > >>>>> Also you don't mention the FS used in each case, so I'm wondering i= f > >>> you > >>>>> used a ZFS install of FreeBSD which could help to explain things. > >>> > >>> > >>> -- > >>> Sean Chittenden > >>> se...@chittenden.org <javascript:> > >> Hi, > >> > >> There is a fresh thread about this in postgresql-hackers [1]. > >> > >> There are two parallel approaches suggested there, where one is to hav= e > an > >> option to continue using the old SYSV shared memory in PostgreSQL, and > the > >> other is the suggestion that "somebody needs to hold the FreeBSD folks= ' > >> feet to the fire about when we can expect to see a fix from their side= ." > >> > >> Looking at the original post in this thread, it seems to me that FreeB= SD > >> has scalability problems beyond what the SYSV vs mmap change in > PostgreSQL > >> introduces? Check my test of PostgreSQL 9.2 vs 9.3 on FreeBSD 10.0 at > [1]. > >> The difference between PG92 and PG93 is not huge, ~17%. The difference > >> between FreeBSD and the other OS:es in this thread's original post's > >> performance chart seems to be about a lot more? > >> > >> Palle > >> > >> [1] > >> > http://www.postgresql.org/message-id/2AE143D2-87D3-4AD1-AC78-CE2258230C05= @FreeBSD.org > >> _______________________________________________ > >> freebsd-performance@freebsd.org mailing list > >> http://lists.freebsd.org/mailman/listinfo/freebsd-performance > >> To unsubscribe, send any mail to " > freebsd-performance-unsubscribe@freebsd.org" > _______________________________________________ > freebsd-performance@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-performance > To unsubscribe, send any mail to " > freebsd-performance-unsubscribe@freebsd.org" >
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