Date: Mon, 10 Feb 2014 10:24:07 -0500 From: Glen Barber <gjb@FreeBSD.org> To: Tim Daneliuk <tundra@tundraware.com> Cc: freebsd-stable@freebsd.org Subject: Re: And Here I Thought buildworld/makeworld Was IO Bound Message-ID: <20140210152407.GB1629@glenbarber.us> In-Reply-To: <52F8E8C6.2060909@tundraware.com> References: <52F84AF8.8050007@tundraware.com> <52F86768.9000109@googlemail.com> <52F8E8C6.2060909@tundraware.com>
next in thread | previous in thread | raw e-mail | index | archive | help
--6FinHCQBQ0zFDOqT Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Feb 10, 2014 at 08:57:10AM -0600, Tim Daneliuk wrote: > On 02/09/2014 11:45 PM, army.of.root wrote: > >Am 10/02/14 04:43, schrieb Tim Daneliuk: > >>For some years now, I have been doing nightly builds of -STABLE > >>on an old Pentium D machine with 2G of memory. Buildworld + 2 > >>different kernels was taking in the neighborhood of 3 1/2 hours or so > >>to run. > >> > >>I then upgraded the Mobo/CPU to a Haswell Quadcore I5-4570 and, sure > >>enough, the build time for all the above came down to 30-35 mins or so. > >> > >>"So", says I, "I'll bet a faster drive would help considering all the > >>scribbling to the disk the compilers and makes do". So, I upgdared to > >>a Kingston SSD Now 300, 120G hard drive and he time to do the above > >>went down to .... wait, it's still about 30-35 mins ???? > >> > >>So, I've tried fiddling with different values for -j on the make > >>command line to little avail. Well, -j8 and -j16 show no real > >>difference here. > >> > >>So is the bounding function here actually CPU not IO? Am I missing > >>something? > >> > >>Thanks, > >> > >>P.S. Trying now with no -j arg on make invocation. > > > >Hi, > > > >the new machine has a lot more memory, I assume. >=20 > Yes, 8G as opposed to 2G. I suppose I could bump it out > to 16G and see if this makes any material difference with > even more cache space. >=20 > >The build probably will not even hit the disk due to caching. >=20 >=20 > Well ... it has to hit the disk sooner or later. But, if the > frequency of physical writes is low because of aggregated > IO from the cache, I guess that would tend to make the whole > business more CPU bound than IO bound. I just found this surprising. >=20 What is the underlying filesystem? > > > >Also remember, the build process spawns probably millions of processes a= nd that alone takes some time. > > > >And 30min sounds pretty great to me :D >=20 > Yeah, I wonder what other people are seeing for a full buildworld/kernel = and/or what > the master machines at FreeBSD.org do in this regards. >=20 > Would anyone else care to share with the class? >=20 If you mean "what do the machines do with regard to tuning", the only specific tuning is turning off atime. If you mean "what do the machines do as far as overall build time", with a clean obj/ directory, 35 minutes sounds about right. I do not have exact numbers. The machine that currently produces weekly snapshot images uses '-j10' for buildworld and '-j6' for buildkernel for each build. It also runs the builds in parallel. Even with three parallel 'make -j10 buildworld' (one for head/, stable/10/, and stable/9/), disk IO is minimal. The only time the disk IO becomes a bottleneck is when creating the distribution files (base.txz, kernel.txz, etc.). Glen --6FinHCQBQ0zFDOqT Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (FreeBSD) iQIcBAEBCAAGBQJS+O8WAAoJELls3eqvi17QTsgQAI7AFT8oJ5S4cldDMCgAxyrx irQoGSLCTCdIzTlOMKHbG6O4InDPN5SwBZj6+91tAAjYQA/WefYqQCJ7U2/no9ga VFtp6No1q2UI56Gf2rV04w6kScoTLnRzOriT+fkqE9t/YG642CBwll7MREpv0JUI AmMPjGCt5Tc77cQwvDk/iwhMZYzs4RVVW2Vpvb0Cv6iMYUFXmw/xdW6vIKciTuUX 2YGSWjFzORK1LMrICzFbppmwMb94Gr7mcKC1TeYZAONiuUFg0LzsW+pWU1K0wHQb P8Ph2PVuYHctbZYPd4vBIVX6i4R809w0rK6bbW71FsGTGQIysxWNksmADXXKTzG2 1Vjg27hUbLJKJm0h3guAdz3mBIUPc0apT2ixSccO6KvNsfqgc0a90d2nCO+8z3bW OTfMqu0NLnoeoxMqhcDyKwrsfB2H+tli5w+JvlvKSO4TthvDL3R0uP2GjIc8L7as BnbFtd47Cd/EJLALmLzE63thLTHvH04Uls7CJML3TuLWrAtnMeAOwux/gxzzBUiX VCfGj+Klt+vkQL/0bpT06sJ4s4zl00xz5qM99PNudo7QUxhKiJ3DtdeOEMLAbkSG fTMII0GtIJWCDrnO2pa8bI6V8MCfJx2azVJ4FbYDkXW/PlFmnyxA473NCoDdIoGt YpCgsfS28MppyynaNRVL =EfKs -----END PGP SIGNATURE----- --6FinHCQBQ0zFDOqT--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20140210152407.GB1629>